In the previous two issues, we looked at the way batteries store energy. We could in fact compare a battery to a conventional fuel tank because the battery and the tank both store energy; but one big difference between a fuel tank and a battery is the process of storing the energy. Petrol and diesel fuel are pumped into the tank in liquid/chemical form and then stored in the same form. Meanwhile, a battery is charged using electrical energy that then has to be converted (within the battery) into a chemical form so that the energy can be stored.

One of the big problems for many potential owners of pure electric vehicles is the relatively slow process of
re-charging the batteries compared to the short time that it takes to re-fill a petrol or diesel fuel tank. If the battery is getting low on energy, the driver then has to find somewhere to re-charge the batteries, and this leads to what is now being termed ‘range anxiety’ for drivers.

Whilst some vehicle owners might only travel short distances and then have the facility to re-charge batteries at home, not all drivers have convenient driveways and charging facilities. Therefore, batteries will have to be re-charged at remote charging points such as at fuel stations or motorway services; and this is especially true on longer journeys. The obvious solution is a hybrid vehicle where a petrol or diesel engine drives a generator to charge the batteries and power the electric motor, and for most hybrids the engine can also directly propel the vehicle. However, much of the driving will then still rely on using the internal combustion engine that uses fossil fuels and produces unwanted emissions. The pure electric vehicle therefore remains one long term solution for significantly reducing the use of fossil fuels and unwanted emission, but this then requires achieving more acceptable battery re-charging times.

Charging process and fast charging
Compared with just a few years ago, charging times have reduced considerably, but there are still some situations where fully re-charging a completely discharged electric vehicle battery pack can in take as long as 20 hours.  It is still not uncommon for re-charging using home based chargers or some remote chargers to take up to 10 hours or more.

Although there are a few problems that slow down charging times, one critical problem is the heat that is created during charging, which is a problem more associated with the lithium type batteries used in nearly all modern pure electric vehicles (as well as in laptops, mobile phones and some modern aircraft). If too much electricity (too much current) is fed into the batteries too quickly during charging, it can cause the battery cells to overheat and even start fires. Although cooling systems (often liquid cooling systems) are used to help prevent overheating, it is essential to carefully control the charging current (or charging rate) using sophisticated charging control systems that form part of the vehicle’s ‘power electronics systems.’

Importantly, the overheating problem does in fact become more critical as battery gets closer to being fully charged, so it is in fact possible to provide a relatively high current-fast charge in the earlier stages of charging; but this fast charging must then be slowed down quite considerably when the battery charge reaches around 70% or 80% of full charge. You will therefore see charging times quoted by vehicle manufacturers that typically indicate the time to charge to 80% rather than the time to fully charge. In fact, with careful charging control, many modern battery packs can achieve an 80% charge within 30 minutes or less; but to charge the remaining 20% can then take another 30 minutes or even longer.   

Battery modules
Many EV battery packs are constructed using a number of individual batteries that are referred to as battery modules because they actually contain their own individual electronic control systems. Each battery module can then typically contain in the region of four to 12 individual cells.  One example is the first generation Nissan Leaf battery pack that contained 48 battery modules that each contained four cells, thus totalling 192 cells; although at the other extreme, the Tesla Model S used a different arrangement where more the 7,000 individual small cells (roughly the size of AA batteries) where used to form a complete battery pack.

The charging control systems can use what is effectively a master controller to provide overall charging control. In many cases  the electronics contained in each battery module then provides additional localised control. The localised control systems can make use of temperature sensors that monitor the temperature of the cells contained in each battery module. This then allows the localised controller to restrict the charging rate to the individual cells to prevent overheating. Additionally, the localised controller can also regulate the charging so that the voltages of all the cells in a battery module are the same or balanced.

One other problem that affect battery charging times is the fact that a battery supplies and has to be charged with direct current (DC) whereas most charging stations (such as home based chargers and many of the remote charging stations) provide an alternating current (AC). Therefore the vehicle’s power electronics system contains a AC to DC converter that handles all of the charging current. However, passing high currents through the AC to DC converter also creates a lot of heat, and therefore liquid cooling systems are again used to reduce temperatures of the power electronics. Even with efficient cooling systems, rapid charging using very high charging currents would require more costly AC to DC converters; therefore, the on-board AC to DC converter can in fact be the limiting factor in how quickly a battery pack can be re-charged. Some models of electric vehicle are actually offered with options of charging control systems: a standard charging control system which provides relatively slow charging or an alternative higher cost system that can handle higher currents and provide more rapid charging.

Home & Away
One factor to consider with home based chargers is that a low cost charger could connect directly to the household 13-amp circuit, which would provide relatively slow charging of maybe 10 hours for a battery pack. However, higher power chargers are also available that connect to the 30-amp household circuits (in the same way as some cookers and some other appliances); and assuming that the vehicle’s AC to DC converter will allow higher currents, then the charging time could be reduced to maybe 4 hours operate (but note that all the quoted times will vary with different chargers and different vehicles).

Finally, there are high powered chargers (often referred to as super-chargers) that are usually located at motorway services or other locations. These super-chargers all provide much higher charging currents to provide fast-charging (as long as the vehicle electronics and battery pack accept the high currents); but in a lot of cases, these super-chargers contain their own AC to DC converter, which allows direct current to be supplied to the vehicle charging port. In effect, the vehicle’s on-board AC to DC charger is by-passed during charging thus eliminating the overheating problem and the high current DC is then fed directly to the battery via the charging control system.

In reality, the potential for re-charging a battery pack to 80% of its full charge in 30 minutes or less usually relies on using one of the super-chargers, but battery technology and charging systems are improving constantly, so we
will without doubt see improving charges times for
newer vehicles.  

Since retirement, I’ve found my Dad reflecting on his time in the motor trade; all the memories, good days, bad days and everything in between.

The one thing he misses is the customers. Not the work, the vehicles, or any other aspects of the business – okay, maybe he misses some of the trade contacts, but this article isn’t about them. We were lucky, we had more than our fair share of fantastic customers, but we also had others that would make your blood boil. And the problem with the latter is that they breed feelings of ambivalence towards customers in general. I’m fairly confident in guessing that you will know what
I mean.
    
Why is it then that a proportion of the people that we deliberately lure towards our businesses provoke these mixed feelings? Well, I think it’s all about expectation. More specifically, the conflicts that arise when there is a difference between what we expect to happen and what actually happens. Some of these conflicts might be avoided by different approaches to communication. Sometimes there are more fundamental issues at stake; maybe the fit between the business and the customer just isn’t right?
    
We’ll return to this idea of fit in a subsequent article as it cuts straight to the heart of our respective business propositions but before we do that, it will help if we understand better both ourselves and our customers. We’ll begin with the troublemakers…
our customers.
    
Is everyone going to be a suitable customer for our business? No, so we need to identify those who could be. For those of us with workshops, it should go without saying that our customers should be vehicle owners (which we’ll loosely take to mean as anyone that has an interest in the successful functioning and care of a vehicle). We can subdivide this group in to private vehicle owners, fleet owners, leasing companies, etc. (note how these groups will have their own more specific interests). Other subgroups might be created using assumed-wealth (poor or rich), make of vehicle (as might be relevant to manufacturer dealerships or independent specialists), or customer and workshop locations (rural or urban) etc. Selecting parameters for such breaking up is never easy; however, once segmented in this way, we are better able to characterise specific customers. On that path lies the understanding
we seek.

I am sure all diagnostic technicians out there will agree vehicles are becoming ever more difficult to diagnose. Two obvious reasons include the increase in networked systems, and difficult accessibility.

The first step is to conduct a non-intrusive serial evaluation. This method often provides insufficient information to progress directly to a repair solution. What if the problem is a non-monitored component, or possibly a non-monitored component causing a negative reaction in a monitored component? Sounds confusing, then you will appreciate the following diagnosis and repair review.
Here is a conundrum: What has a vibration at around 100hz got to do with a EGR fault?  

The vehicle in question is a 1.4 16v mk4 Golf 1J chassis. The vehicle history is very well known to us as it was owned by our staff member, Annette. She had it well maintained for many years despite its 125,000 miles.

It had a minor serial error relating to EGR flow. A new OE valve was fitted many years ago without success. The vehicle performed extremely well so we ignored it. The vehicle passed into my ownership several weeks ago. My intention was to prepare it for my partner’s two sons as their first car. Totally new OE brakes front and rear, four new Goodyear 185/65/14 tyres… anyone spotted an anomaly yet?

Rear wheel bearings re-packed with grease, all fluids replaced. New OE exhaust system. The car drives superbly. Brake balance differential 1%! Perfect emissions. I decided to use the car for the Pico NVH-WPS course held during a weekend in November. On the Saturday we conducted several tests to confirm the mechanical efficiency of the engine.

The primary test, following a battery status and health check, was a relative compression test conducted in the Pico diagnostics platform. It’s very quick with only the battery connected to channel 1.

The result was excellent, all cylinders returning a differential of 100%. Let’s digest this for a moment, this does not confirm good compression or correct valve timing. It’s simply a balance of voltage drop whilst cranking the engine. You know what, a bad result here always indicates a serious internal engine problem.

Testing
We then discussed the issue of pumping losses and how this can be addressed with throttle control, variable valve timing and lift, and not forgetting cylinder cancellation! This progressed to dynamic compression tests on the engine using WPS. The results were excellent showing good pressure differential (note I don’t call it vacuum as there is no such thing) suggesting efficient cylinder and
valve seal.

The day ended with a prep talk on the advantages of noise and vibration monitoring. Sunday began discussing the information required for manual data entry into NVH platform. This includes PIDs, notably engine speed via a Mongoose serial interface. All the gearbox and differential ratios were entered together with the tyre sizes. Did you spot the anomaly yet?

Basically, the software can now calculate frequency and speed against noise and vibration signatures across all engine, gear selection, and wheel speeds. Remember frequency HZ x 60 = RPM.

RPM div 60 = HZ. Down the road we went several times sticking weights everywhere to demonstrate different vibration signatures. Due to the quality tyres and general smoothness of the car there was very little vibration to look at.

However, on closer inspection there was a vibration concern around 100 HZ. Apply the maths and you get 6,000 RPM. The engine E1 was around 50HZ! 3,000RPM and there was a E2 vibration, so whatever it was had to be  engine  ancillary related. Further inspection using a roaming microphone to pin point the noise confirmed a very noisy serpentine belt idle pulley bearing. This is where the shock on my part and the realisation of the incredible value of applying science and physics to an everyday problem pays off. I decided to conduct the repair myself the next day, stripping the front end exposed a fractured timing belt guide and badly impregnated timing belt tension pulley. The broken half of the guide was hovering inside the timing cover I guess just waiting to do its worst!

Pic pulleys
Several pulleys were singing like canaries despite no previous and obvious audible noises. So, three hours later and a total front end rebuild with OE parts, including water pump, we have an even sweeter engine. So, what else did I find? My original training was as a precision engineer specifically in engine remanufacture so instinctively I don’t strip out timing assemblies until I have checked the original position. It was one tooth out on the crankshaft!

Humming, I think timing out, manifold pressure will change, it’s a MAP sensed load system, so EGR is calculated from an algorithm based on throttle, map value and EGR control ratio, with feedback.

Eventually we discover the historical problem of a seemingly innocuous EGR DTC. In conclusion by recording vibration from the driver’s seat frame, yes, I do mean from inside the car,
we pin point a potentially engine critical fault.

A mechanical non-monitored component affecting a monitored sensor value! One last thought – the anomaly! The standard tyre specification for a Golf 1.4 1J IS 185/80/14. I deliberately wanted more responsive high-end tyres. The speedo is almost 10mph out, not a bad idea for two 24/25-year olds.

Want to know more?
If you want to get on the NVH bandwagon, email Annette @ads-global.co.uk or call 01772 201597.

Into 2018, John looks at the steps you need to take to make your workshop more efficient, while obeying the Laws of Diagnostics

In the first article in this series, published in the November issue, we looked at some of the issues relating to the batteries used in electric and hybrid vehicles. As brief summary: Modern lithium based batteries typically store four times more energy than a traditional lead-acid battery of the same weight.  

Definition of uncertainty:
a state of having limited knowledge where it is impossible to exactly describe the existing state, a future outcome, or more than one possible outcome.

I have always tried to express the importance of logic and process in any diagnostic challenge. Added to this foundation training principle should be common sense and simplicity.

There’s no doubt about it-  the technical challenges that face an independent workshop grow daily and this has the ability to not only affect the commercial performance of the business but also the morale of those at the sharp end.

I'm not the nautical type, but I know that setting sail without sufficient preparation is foolhardy and the likelihood of you reaching your destination in a timely manner, at an agreeable cost with a healthy profit margin would be highly unlikely.
Why then do we set off into ‘technical repairs’ without preparation, but remain surprised when we meander into fog, or ends up on the rocks... No I'm not sure why either.

Elements for success
How do we avoid the perils? It's quite straightforward. The amazing thing is that the components for a smooth journey can be applied to any repair regardless of vehicle or system. So what do you need?
 

Having recently presented short seminars about electric vehicle technology at Top Tech Live, and at some other trade events, it has become clear that technicians are only slowly beginning to delve into the
world of electric and hybrid vehicle technologies.   

This month I have chosen a subject from a recent visit to NTN SNR at their Annecy plants in the Rhone alps region of France.
Last week found me at Lyon airport, thankfully not with Ryanair. There are seven plants, if my memory serves me correctly. It is a proud French company with global facilities in the far east, central Europe and the Americas. Their adopted company language is English- so much for Brexit and ill feelings. Take it from me it does not exist, except in the minds of the idiots we call politicians.
The company produces a huge range of bearings for a cross section of transport segments such as light vehicle and public transport. This includes the incredible demands of the TGV, commercial vehicles, and earth moving plant and aerospace such as Airbus and others.

This subject I hope, brings some reality into what is often expressed as an emotive opinion without substance or fact-based evidence.

We need to talk about security. Why? Because deliberately or not, its effects are mutating our opportunities within the automotive aftermarket. We need to understand more about it and, at some point, to try to anticipate the eventual set of circumstances to which it might lead. As they say, forewarned is forearmed.

We’ll begin by looking at an example of a recent security system and checking out its inner workings. We’ll review its potential vulnerabilities and assess the need for, and impacts of, increased security. First though, we’ll cover some general concepts, to keep in our minds the bigger picture regarding possible motivations for increased security.


Security
Security is the protection of things having value, where they might be at risk from theft or attack; i.e. when they have, or are perceived to have a vulnerability. Security aims to prevent an agent of ill-intent (e.g. criminals, intruders, missiles, or computer-viruses etc.) from gaining access. The consequence of this is the introduction of barriers to those requiring legitimate access, such as owners, occupiers, citizens or data-holders. This dichotomy is at the heart of all security implementation issues. This always begs the question; what level of security balances an intended degree of protection from risk, with the subsequent barriers to legitimate access or freedoms?

As the assessment of risk primarily determines the necessary level of security, it is not hard to imagine that superficially legitimate security concerns can be used to justify limiting access to a favoured group. It’s a simple trick, just inflate the perceived risks and exaggerate the vulnerabilities where necessary. A similar mechanism can be used in a health and safety environment, where legitimate but undesirable behaviours in the eyes of the decision makers can be quashed by deliberate overstatement of the perceived risks. When loaded with the weight of moral absolutes (“lives are at stake”), the arguments seem powerful but are they really intended to shut-down reasoned debate regarding the actual risks? Anyway, the point is, we cannot have a reasonable discussion regarding proportionate levels of security without being able to properly assess potential vulnerabilities and associated risks.


Immobilisation
Vehicle immobiliser systems have been developed to protect vehicles from theft. There is a clear need for the security as the risks are very real. Car thefts were far more common prior to their development. Such systems work by only allowing vehicle mobilisation when a key, placed in the ignition switch, is from the unique set authorised to start the vehicle. The following describes a representative immobiliser system and its behaviour during ignition-on and engine-start conditions, just after the car has been unlocked. As we will be discussing potential vulnerabilities, the make and model is not given.

Component-wise, such systems usually consist of a transponder in the key head, a transponder coil around the ignition switch and an immobilisation control system within either a dedicated immobiliser control module, or another control unit, such as the central electronics module (CEM). The CEM might be hard-wired to an immobiliser indicator in the dashboard or instrument cluster (IC), to indicate the system’s status to the user. The CEM will communicate with the engine control module (ECM) using a CAN bus. Note that, if the CEM is on the medium-speed CAN bus and the ECM on the high-speed CAN bus, then a control module that is connected to both buses, such as the IC, will need to act as a gateway to communications between the two.

There are usually two stages to the authorisation/start process; the first, a key checking phase, is initiated when the key is placed in the ignition barrel and the second is a start-authorisation phase, instigated when the operator turns on the ignition.
A typical key checking phase might progress as follows (see Figure 1 for the representative signals): initially the system will be in an immobilised state, indicated by periodic flashing (e.g. once every two seconds) of the immobiliser indicator. When the key is placed in the ignition switch, the CEM energises the transponder coil (e.g. at 125 kHz), which excites the transponder. The transponder responds by transmitting identification and rolling code data to the CEM via an inductive voltage within the transponder coil circuit. The CEM will check the returned data against the stored data to confirm its identity. The CEM might double-check the key identity using the same mechanism.

The start-authorisation phase proceeds as follows: When the ignition key is turned to position II (ignition on), the ECM detects the ignition supply voltage and sends a start request CAN message to the CEM. If the key is valid, the CEM responds positively, with a code derived from the message contents sent by the ECM. In return, the ECM replies to confirm that the vehicle is in a mobilised state and that it can crank and run the engine. Upon receipt of this confirmation message, the CEM can illuminate the immobiliser indicator (e.g. with a one second confirmation flash) and then turn it off. If the key is invalid, the CEM will respond negatively to the ECM’s start request message, such that the ECM will not crank or start the engine, and the alarm indicator will continue to indicate an immobilised state.


Insecurity
The immobiliser’s subsystems could be vulnerable to several types of attack: Key recognition; The key recognition subsystem, consisting of the CEM, transponder coil or and transponder, could be prone to attack if the correct rolling codes could be transmitted in the right way and at the right time. Note that to move the vehicle, the correct mechanical key would need to be in place to remove steering locks etc. Key-less start systems present other sequencing issues (related to direct CAN messaging, described below), which would need to be co-ordinated with the press of the engine start button etc. The biggest vulnerability and simplest way to attack the system is to clone an authorised key.

Direct access to the CAN bus; If the start-request from the ECM and subsequent immobiliser related messages can be intercepted and the appropriate (algorithmically generated) response codes returned, then the CAN communication system could be used to carry out unauthorised mobilisation of a vehicle. The method would rely on a controllable communication device having a physical connection with the CAN bus. Timing is important (the messages are often expected to be received within a certain time frame) and the genuine responses that would be sent out by the immobiliser controller would need to be mitigated against (e.g. the filtering out of its likely negative response to a start request, that might cause the ECM to immobilise itself).

Aside from the practical connectivity and the sequencing issues, there is the issue of knowing how to generate the correct response codes to a start request. Although, the codes are observable in an unencrypted network, the relationship between the in and out codes can be extremely difficult to calculate using analytic methods alone and are more likely to be determined from reverse engineering of the control unit’s program files. Aside from the legal implications, the challenge is still great, which is very likely why it has not appeared to have happened.

Indirect access to the CAN bus; Given the potential difficulties of physically placing a communication device on the CAN bus, an alternative approach is to hijack a device that is already connected. Any internal (software or hardware) system within a connected control module that has access to the controller’s CAN interface might provide a channel through which unauthorised access could be attempted (especially if a vehicle manufacturer has already built-in a remote starting capability).

It is this type of attack that has been highlighted as a particular concern with the advent of connected vehicles, purportedly presenting hackers with opportunity to remotely control some or all of a vehicle’s functionality. There have been notably few examples of vehicles being hacked in this way and it will be very interesting to see if that changes over the coming years.
All in all, the challenges needing to be overcome to take advantage of any the three perceived vulnerabilities and to steal a car are great. Quite simply the easiest form of attack is to clone a key. The question is then, what are the motivations for ill-intentioned agents to attack our automobiles and are they likely to want to try to steal a car through attacking the immobiliser system? I’m not sure I’m qualified to answer that.


Information
There is a further, related, development that has already dawned within our automotive landscape. Our modern motor vehicles are capable of generating significant volumes of personal data regarding much of our travel and lifestyle habits. This information is hugely valuable. Google’s company worth is colossal and their value is driven purely by their knowledge of our online browsing habits (through the use of their web applications). For the most part, we are not always online. Imagine though, if they could collect a raw feed of data regarding our offline habits, such as those we might create when we travel within our vehicles. How much would the company that had access to that data be worth? With that thought, it is clear why tech firms are falling over themselves to tap into our automotive existences.

Given that all this valuable data is flying around unencrypted vehicle communication networks (much of it is required by engine, navigation, entertainment and ADAS systems etc.), why in their right minds, would the vehicle manufacturers not want to encrypt that data and keep it to themselves? By doing so they would be able to prevent any third parties, including (coincidentally) aftermarket diagnostic tool manufacturers, from having any access to a vehicle’s CAN bus data, without the vehicle manufacturer’s prior consent.

Now, in that context, wouldn’t it be convenient if the vehicle manufacturers jumped upon the reports of the hackers’ abilities to put lives at risk, so as to justify the encryption of vehicle networks? Conspiracy theory? Maybe. I am susceptible. I once imagined that the large discrepancy between real-world and quoted fuel efficiency figures could have been indicative of an OE-level distortion of engine test results…


Further tech info
http://automotiveanalytics.net/agile-diagnostics

The exhaust is a lot more than just an exit route for waste gases for some time now. Tim Howes, deputy general manager – supply chain and technical service, NGK Spark Plugs (UK) Ltd, provides some context: “In 2009, The Euro V emissions standard for passenger cars demanded a significant reduction in NOx, HC and particulate matter and in 2014 the Euro VI standard brought a further tightening of these emissions, primarily for diesel engines.”


Complexity
For diesel powered vehicles this has meant a significant increase in the complexity of exhaust gas recirculation (EGR) and after treatment resulting in the fitment of various combinations of diesel oxidising catalyst (DOC), selective catalytic reduction (SCR), lean NOx trap (LNT),  diesel particulate filter (DPF) and other associated devices and control systems.
All these additional components have led to an increased need for sensors in the system.

I have been asked several times about ABS wheel sensors. Like many other components, the technology is changing. The changes reflect the expansion in integrated chassis dynamics.

Just imagine how many functions require wheel speed and rotational differential data.

ABS, dynamic stability, hill start, audio volume, navigation, self park, all wheel drive, active steering assist, electronic handbrake etc. Sharing this data on a high speed can network ensures very accurate vehicle motion dynamics.

Older variable reluctance sensors (VRS) rely on a coil generating an alternating voltage when rotation occurs. The problem is they are not directional sensitive and cannot report motion at very low speed. Air gaps were critical as they affect signal amplitude. They are often referred to as passive sensors. So, the introduction of digital or active sensors was inevitable.


Principles
How do we tell them apart? Active sensors require a voltage supply from the ABS PCM, with a ground or signal return. They operate with different principles of signal generation; hall, and magneto resistive. Pure hall effect sensors will switch between the supply potential voltage and ground. Magneto resistive sensors operate on the principle of current and voltage change in response to a change in magnetic induction. This change can be introduced in several ways reflected in wheel bearing and sensor design. Smaller sensors with integrated magnetic field rings are now the norm. Developed by NTN at their Annecy facility they are called encoded bearings. A small ring mounted at one end of the bearing carries a series of north south poles. These have now been replaced by dual encoding, two sets of magnetic rings with a unique offset. This enables the abs module to determine direction of rotation.


Subtle differences
There are two very subtle differences in the digital outputs. They can be called pull up or pull down. The sensor supply voltage will be slightly lower than battery voltage this is due to the different internal resistance values. However, it will be around 10.5/11.5v.

The ground or return signal value will vary between 0v or 1.4/1.8v. You could have a sensor or circuit fault; let me try and explain the subtle differences, and how to prove which is which. Remember the golden rule if in doubt compare a wheel circuit that works normally.

First unplug the sensor and measure both circuits in the loom. With no load applied the supply voltage should jump up to NBV

Next check the ground circuit if its true ground then it’s a pull-down type and the signal will be on the power line, and may only be around 200mv

If a small voltage exists then it’s a pull up type and the signal will be on this wire not the supply. The digital signal will be very small when the wheel rotates. It could be small around 200/400mv, or as high as 0.5/1.8v, depending on the manufacturer variant

Common sense would dictate the serial route is easiest, however how would you determine an intermittent fault? It could be a faulty sensor, faulty encoder, or a circuit error. The only way is using a scope. Should we measure voltage or current though? Both change in the circuit. Unless you have a very special current clamp, go for voltage and select a AC coupling.

The specific question I am often asked is current measurement, well I can tell you in a pull-down circuit its around 7-15 ma with a 400mv voltage change. The pull up type will produce around 6/13ma with 0.2/0.35mv.     However, these voltage values can vary due to the value of the two parallel internal sensor resistors these are normally 1.4k ohms, with a much higher resistor in the meg ohm range, within the ABS pcm.

I hope this helps. The pico image was taken from a VW Golf 1.4 TSI. The easy bit is replacing the wheel sensors. Ever since metal housings were replaced with plastic they never corrode in the housings
do they…?

The need to adapt to changing vehicle technology is one of the main challenges of our time in the sector. Increasing connectivity and a vastly more complicated conventional vehicle provide a whole raft of obstacles on their own, before you even get to the rise of electric vehicles and hybrids.

Add to that a more uncertain legislative environment resulting from rules not quite keeping up with the technology coming in, and you’ve got yourself a whole host of issues that the entire industry needs to stay on top of if it is going to continue to offer a sterling service to customers.

Let’s look at electric vehicles. For Tom Harrison Lord from Fox Agency, the b2b marketing company specialising in the automotive sector,  Automechanika Birmingham offered a troubling glimpse into the future:  “This summer’s Automechanika Birmingham was entertaining and enjoyable as ever, but it also exemplified a worrying trend in the motor industry today. With the advancement of electric vehicles, there are going to be some rapid and stark changes ahead. The automotive aftermarket, however, seems to be burying its head in the sand.”


Access
The key, as it has been in the past, is access. In this case, the right to be able to repair vehicles. Think that’s all sorted? Perhaps not:  “The rise of the electric cars and vehicles is something that could hit the automotive aftermarket hard – in particular, independent garages.

“Many, if not all, electric vehicles invalidate their manufacturer warranty if essential work is carried out on the electrical systems by someone other than the main dealer. What’s more, many cars with batteries, such as the Mitsubishi Outlander PHEV, have warranties on the electrical components lasting up to ten years.

“Having no choice but to use the main dealer for a full decade shows just why independent workshops will have fewer vehicles coming through the doors in the years ahead.”

Do our own workshop war stories point to a diagnostic way forward asks  James Dillon

Barnaby Donohew examines how the aftermarket can learn from the tech sector to improve diagnostic outcome

It’s only when you visit the past that you realise how far the journey to the present has taken us. Some time ago Martin, a very good friend of mine from Londonderry, sent over a set of very early EVL Bosch injectors.

This injector pattern started life around the late 1960s and ran through to the mid 1980s and was used by Ferrari, Volvo, Opel, and many others. The set supplied to me came out of a VW camper van, and like many from this era were badly rusting and contaminated from in-tank corrosion. At the time fuel lines and tanks were made from untreated mild steel, and filtration did not meet current standards of 5 microns, or 2 microns with the latest HDEV 6 injectors. The biggest single cause of wear and failure was water ingress in gasoline due to condensation and external ingress.

The injectors were in a bad condition, sticking, blocked, and dribbling. I started the cleaning process with an external pre-clean ultrasonic tank before risking contamination in our ASNU bench. Several cleaning sessions later, with a varying degree of improvement, we arrived at a fully serviceable set.

I posted them back assuming it would be the last of my involvement. I should have known better. Martin and Matthew at Conlon motors have been involved with our training programme over many years. I travel over there several times a year for onsite training, and you have guessed it, waiting for me on my last visit was the camper van.

It was running extremely rich, blowing blue smoke. You could taste the emissions. If you have ever followed a vintage car you will know what I mean. This is where a trip down memory lane started.  I have not worked on this system for many years.  In fact it was on systems like this that our current-day diagnostic processes were developed.

Our industry is in a constant state of flux; new technology and changing customer behaviour are impacting our organisations, and ultimately the financial success of your business.

Frank Massey looks at how you need to always keep an open mind on diagnostic methods

Even apparently simple problems require thorough investigation if you want to diagnose faults right the first time

Two months from now will bring my tenure in the motor industry to 49 years. I would like to think I have evolved, kept up with technology, enabling me to provide a professional service, enjoying customer respect and integrity. My focus has been the technical challenges, while my son David manages the commercial responsibilities.

"Electronic Lego" is a phrase that was introduced to me by an engineering manager when I worked for the diagnostic company Crypton around 25 years ago. In the late 1980s the Company had developed engine tuning machines which moved away from bespoke central processing units (the so called Big Box tuners) to a PC based system. The elements of the PC based system could not just be bought and fitted together (like lego) and be expected to work. The PC components and peripherals had to be carefully selected, including the compatibility of their drivers and software to ensure a robust PC based diagnostic machine could be created. Over the past 10 years or so motor vehicles have moved away from their previous Lego like construction, where replacement parts were free to be plugged in and replaced at will. The change was due partly to the modern vehicle being constructed as a rolling network of computers and partly to the advent of the factory fitted immobiliser, where transponder keys and the relationship between vehicle computers became prevalent.

I gave this topic some considerable thought before choosing to discuss not just a selection of tools we use, but also some tools we have designed and modified.

By James Dillon

By Frank Massey

By ACtronics

We began this journey last issue, so to recap: We need solid reasoning skills to carry out effective diagnostics; persistently good decision making doesn't happen by chance. Possibly out of convenience these skills are often underestimated and undervalued by people, both in and out of the trade. We must raise awareness of the discipline and precision of thought necessary for logical and critical thinking: so we can be better rewarded for our efforts; and to make sure they are consistently and properly applied.

Reasoning, arguments and hypotheses
We covered some fundamentals in my last article: we explain our reasoning using arguments, which contain statements supporting a conclusion; one type of argument, a deductive argument, should guarantee the truth of its conclusion (if it is sound); however, we need to use critical-thinking to check this, by making sure i) there are no other possible conclusions (which makes it a valid argument) and ii) the supporting statements are true.

Diagnostics is all about decisions. And what is a decision? It is a conclusion or resolution reached after consideration. Therefore, efficient and effective diagnostics is about drawing the right conclusions at the right time. How do we do that? Amongst other things, by making sure our logical and critical thinking skills are up to scratch. This series of articles aims to help us with that by looking at the principles of human reasoning.

A couple of interesting workshop repairs have taken my fancy in the recent months, the first involves a BMW 530 common rail diesel.

BTN Turbo

Alldata Repair gives independent workshops direct access to OE repair information via an online portal. The data is unedited - diagrams are not re-drawn and the info is uncut, what you see is the same information available to techs within dealer workshops.

If you've been reading this magazine for any amount of time, you'll be well aware of the obvious benefits of using an oscilloscope when diagnosing faults, but it is the less obvious benefits that with practice can lead to the correct diagnosis.

Q: Why did you feel there was a need to review your code of conduct?

Peeved with the Teves?