Part two The good and THE GREAT
In the second part of his series, Ian Gillgrass shows how following the diagnostic process can turn a good technician into a great
Published: 26 March, 2018
In part one, we looked at the start of the ‘diagnostic process.’ The first steps were customer questioning, confirming the fault and knowing the system and its function. These help the technician to build the ‘big picture’ necessary to repair the vehicle correctly.
In this article we will look at the next four steps.
Step 4: Gather evidence
It is easy to overlook this step as many technicians think of it as the overall ‘diagnosis.’ However, once the technician understands the system, gathering evidence will provide key information. This step is normally best carried out with the use of test equipment that does not mean the dismantling of systems and components.
Many technicians have their own favourite tools and equipment but this list can include (but not limited to)
the following:
Scan tool – It is always best practice to record the fault codes present, erase the codes, and then recheck. This means codes which reappear are still current. Remember that a fault code will only indicate a fault with a circuit or its function. It is not always the component listed in the fault code that is at fault
Oscilloscope – An oscilloscope can be used for a multitude of testing/initial measuring without being intrusive. Some oscilloscope equipment suppliers are looking at systems within high voltages hybrid/electric vehicle technology. The waveforms produced by the test equipment can be used when analysing the evidence and may indicate that a fault exists within a system. An understanding of the system being tested will be necessary to understand the information. This may even include performing sums so all those missed maths lessons at school may come back to haunt you. It may take time to become confident analysing the waveforms, so be patient
Temperature measuring equipment – This can include the use of thermal imaging cameras. Most systems that produce energy/work will also produce some heat. The temperatures produced vary from system to system. Examples include everything from engine misfires to electrical components, as well as air conditioning system components and mechanical components such as brake and hub assemblies. The possibilities are endless and results can be thought provoking.
Emission equipment – By measuring the end result, an exhaust gas analyser can show you if the engine is functioning correctly. The incorrect emissions emitted from the exhaust help indicate a system fault or a mechanical fault with the engine
Technical service bulletins – Many vehicle manufacturers produce technical service bulletins (TSBs) that are generated by a central point (usually a technical department) from the information that is gathered from their network of dealers. Some of these may be available to the independent sector either through the VM or through a third party – It’s always worth checking if these exist. They may indicate a common fault that has been reported similar to that the technician is facing. Some test equipment suppliers may provide TSBs as part of a diagnostic tool package
Software updates – Many vehicle systems are controlled by a ECU. Most vehicle manufacturers are constantly updating system software to overcome various faults/ customer concerns. Simply by updating the software can fix the vehicles problem without any other intervention of repairing a possible fault. This is where having a link to a vehicle manufacturer is vital in repairing the vehicle
Hints & tips – Most technicians will have a link or access to a vehicle repair forum where they can ask various questions on vehicle faults and may get some indication of which system components are likely to cause a vehicle fault
Functional checks – Vehicle systems are interlinked and typically share information using a vehicle network. The fault may cause another system to function incorrectly, so it is vitally important that the technician carries out a functional check to see if the reported fault has an effect on another system. By carrying out this check the technician again is building the big picture
Actuator checks – Most systems today are capable of performing actuator tests. The technician can perform various checks to components to check its operation and if the system ECU can control the component, often reducing the time to the diagnosis, by performing this task the technician can identify whether it is the control signal, wiring or component or it is sensor wiring. This function can be used in conjunction with serial data to see how the system reacts as the component functions
Serial (live) data – The technician can typically review a vehicle system serial data through a scan tool. Having live data readings to refer to can help you review the data captured. Using actuator checks and viewing the serial data can also help the technician to identify a system fault
Remember to record all the evidence gathered so it can be analysed during the next step in the diagnosis. We can’t remember everything. If the technician needs to contact a technical helpline they will ask for the actual readings obtained recoding the data gathered will help.
Step 5: Analyse the evidence
Analysing evidence gathered during the previous steps can take time. The technician needs to build the big picture from all the evidence gathered during the first few steps. You need to analyse the information gathered, and decide on what information is right and wrong.
This step may rely on experience as well as knowledge on the product. You should take your time – don’t be hurried. Time spent in the thinking stages of the diagnosis can save time later. Putting pressure on the technician can lead to errors being made. It may be necessary to ask the opinion of other technicians. If the evidence is documented it may be easier to analyse or share between others.
Step 6: Plan the test routine
After analysing the evidence gathered it’s now time to start to ‘plan’ the best way to approach to the task or tasks in hand.
The technician should plan their test routine, decide on what test equipment should they use, what results are they expecting, if the result is good or bad and which component should they test next.
Document the plan – this enables you to review decisions made at this stage in the next step. The technician may not always get it right as there may be various routes to test systems/components. The test routine may have to be revisited depending on the results gathered during testing. Documenting the test routine will provide a map. Also, don’t forget to list the stages, as this is something that could be incorporated into an invoicing structure later.
The technician should indicate on the routine what readings they expect when they carry out the system testing. This can be generated by their own knowledge/skill or the expected readings may come from vehicle information which they have already sourced. If the information is not known at the time the test routine is planned, then the test routine may highlight what information is required and what test equipment is needed. You shouldn’t be afraid to revisit the plan at any time and ask further questions on which direction the tests should take. If the plan is well documented and the technician becomes stuck at any point, they can pause the process and revisit later. Also the information can then be shared with various helplines that support workshop networks.
Step 7: System testing
The technician then follows their pre-determined plan, if it is documented they can record the results of the test(s) as they follow the routine.
Many technicians tend to go a little off-piste when they get frustrated. Having the routine documented can keep the technician on track and focused on the result. If the routine is followed and the fault cannot be found the technician may have to go back to the analysing the evidence or planning the test routine. The technician shouldn’t be scared of going back a few steps, as I said previously analysing the evidence takes practice and can be time consuming, not to be rushed.
Summing up
Remember to follow the process. It is easy to be led off track by various distractions but don’t try to short circuit the process. Some steps may take longer than first thought to accomplish than others. Some distractions may be outside of your control, and it may be necessary to educate others. Practice, practice, practice. Refine the process to fit in with your business and its practices, the business could align its estimating/cost modelling to the process, being able to charge effectively and keeping the customer informed at each stage of the process.
Coming up...
In the next article I will be looking at the next four steps which are; Step 8: Conclusion (the root cause), Step 9: Rectify the fault and Step 10: Recheck the system(s). The last article in this series will indicate the final three steps and how to fit them all together in order to become a great technician and perhaps succeed in Top Technician or Top Garage in 2018.
- It’s Evoque-ative
I was recently tasked with looking at a vehicle which had the dreaded 500-miles-or-less-until-the-vehicle-cannot-be-started warning on the dash display. We have all been there before with this sort of issue. This is a typical warning you will see on vehicles fitted with an AdBlue emission system if there is a fault present. The vehicle in question was a Range Rover Evoque 2016 2.0TDI.
The customer who brought the vehicle to me was a trade customer. They advised that the vehicle originally came into them for repair for an engine warning light which intermittently illuminated. The fault code was for Nitrogen Oxide (NOX) sensor 2 no signal. I started by carrying out a full system scan of the vehicle as I would routinely do. The result was multiple fault codes stored in the engine management system control module relating to the AdBlue system. Due to having so many codes stored, I checked all the relevant freeze frame data for each code and then erased them. Following this, I attempted to carry out a road test, but a fault code returned almost immediately for no communication present with NOX Sensor B.
Signal and communication
Armed with this information, I thought it would be a fairly straightforward diagnosis. However, I was wrong. It never goes the way you would like it to, especially at the end of the day. I put the vehicle on the ramp and obtained a wiring diagram to check the wiring directly at the NOX sensor. Upon first inspection, it was clear the sensor had already been replaced. I contacted the customer, and they confirmed the sensor was indeed both new and genuine from the manufacturer. I then checked the wiring to the sensor. These types of sensors are fairly straightforward to check because they have only four wires which have signals on. These are power, ground and CAN bus communication. I firstly checked the power and ground and confirmed these matched the genuine wiring schematic. Please refer to Fig.1. Next, I then connected an oscilloscope to the circuit to monitor the CAN bus signal. I found the CAN bus was shorted to each other and what would appear to be 12v. Please refer to Fig.2. The simplest next test was to unplug the sensor and to monitor the CAN bus signal. I found with the sensor unplugged the short was no longer present and the CAN bus signal returned, which would mean that the sensor was faulty wouldn’t it? Please refer to Fig.3.
Slightly concerned I was missing something as the sensor had already been replaced, I decided to contact Neil Currie. As well as being the winner of Top Technician 2019, he is a contributor to this very magazine and a Land Rover/Range Rover guru to boot. He advised me that if the sensor has been replaced and it is a genuine sensor provided by Range Rover, then the pin configuration has been changed and you are required to move the pins around in the connecting plug in order for the new sensor to operate. This has been done due to a change in manufacturer used by Range Rover to produce this style sensor because of a lack of available original manufacturer NOX sensors. The details can be found here from a bulletin released by JLR.
Full system scan
After de-pinning the connector and swapping around pin 2 (CAN) and pin 4 (Ground), I rechecked the CAN bus signal and found the signal is now correct and is no longer shorted. Please refer to Fig.4. After carrying out a full system scan, clearing and resetting the AdBlue counter, I now found that the warning for 500-miles-remaining had, vanished and there were no fault codes returning. This vehicle was now fixed.
I thought this was a very interesting case study as both the aftermarket and genuine diagrams both show the original wiring of the NOX sensor and there is no reference to a modification, unless you are aware of this issue or have access to Range Rover’s technical service bulletins this would certainly take you up the diagnostic garden path. Luckily for me, networking with the finest technicians in the country is a great way to stay up to date with these types of modifications.
- The safe operation of vehicle lifts
In the second part of our series from the GEA, the process of actually buying and having lifts installed is the focus
- Calibrations: All about live data
Live data ensures calibrations are done correctly, but what we are seeing is a growth in the collection of the data from vehicles, whether they are single or multi-site operations. The data is accessed via the SRS module and once it has been harvested it becomes an asset to the business. The reason it is an asset is simple. It is because the data helps the business reduce key-to-key times for calibrations, while also enabling them to identify systems that need calibrating after a collision.
An example of this is when a technician uses the live data from a vehicle on the workshop floor to see the forces put on the car pre-and-post-collision. Once this data is reviewed, it enables the technician to understand where the forces have gone through the car easily. The next stage of the process is for the technician to check and carry out specific calibrations such as the radar at the front of the vehicle alongside any calibrations that are required at the rear to complete the job.
Live data also provides the technician with a safety blanket to ensure that the areas of the vehicle that have been worked on are checked and calibrated correctly before the vehicle goes back on the road.
So, live data helps on the workshop floor, but there are also other potential uses for it by insurers, who would use the data differently from the way the technicians on the workshop floor use it. Insurers would want to read and review the live data straight away from the vehicle that had a collision. Once this has been done and based on what they have seen, they could potentially write off the vehicle there and then rather than having a vehicle assessment done. This would be a cost-saving measure for them as they would not have to pay out for any work done.
We know live data is here to stay because ADAS systems are becoming common place on the newer models of car that are coming off the production line. This means that it is important that the people reading and reviewing the live data have the necessary knowledge and training to understand what they are looking at and the ways the data can help them complete jobs more efficiently and benefit their business.
- Rocketing fuel prices reinforce role of technician
With global fuel prices rising at an alarming rate and with no imminent signs of any significant reduction, vehicle maintenance is now vital. If motorists are aiming for maximum miles from their tank, they can’t afford to overlook vehicle servicing, maintenance, and repairs. No more ignoring the early warning signs or delaying a service. It all points to the importance of the independent technician as the trusted go-to professional.
“Driving fuel efficiently is a subject of significant interest,” said Mike Schlup, MD of Kalimex, the UK distributors of the JLM Lubricants’ range of products. “However, if a tank of fuel is to last longer then vehicle maintenance is more important than simply swapping poor driving habits for good ones. The professional independent technician holds the keys when it comes to attaining optimum vehicle health, because a healthy vehicle burns less fuel. This means choosing high quality additives from the JLM range when they reduce or remove the need for a replacement part and when they enhance the overall service offering.
“JLM is globally renowned for collaborating with top-flight technicians so that new products are road-tested and evaluated in real workshops before they are launched. Darren Darling, founder of the world acclaimed, independent DPF Doctor Network is a JLM brand ambassador, but Darren was putting JLM products through their paces and recommending JLM products long before he accepted this role. So JLM’s focus is very much on developing additives and lubricants that have been evaluated by world-leading technicians on the most challenging vehicles. If motorists want to run their car fuel efficiently and keep repair and service bills down, they must trust their technician to use premium quality additives whenever possible. Take the JLM GDI Cleaner for example. It cleans the tip of the injector of direct fuel injected engines, with more efficient fuel injection and less fuel consumption as a result. With gasoline direct injection, the injectors get dirty and cook on a regular basis over a period of time. This product is used on many vehicles including ones technicians class as hopeless cases. Used every 20,000 km it will keep the injectors clean and will play a crucial part in improved fuel economy.”
Solution
Mike continued: “Another JLM product, Petrol Extreme Clean will improve fuel economy. It’s the solution to late model cars and engines with severe build-up blocking problems in various parts of the fuel system. These contaminations are tough and hard to dissolve with regular fuel additives. This product is suitable for all petrol engines including direct injection with or without a turbo or catalytic converter. The special detergent in the JLM formulation cleans the fuel system including injectors, inlet and outlet valves, spark plugs and combustion chamber. The net effects are lower deposits of combustion residues in the cylinder and cleaner exhaust gases; The octane number boosted by 2-4 points plus an increase in engine power with better fuel economy. All this from a product that is added to the fuel tank before refueling.
“For diesel vehicles, JLM have the diesel equivalent, aptly named Diesel Extreme Clean. This cleans the entire fuel system with lower emissions and fuel consumption as a result. It is also powerful enough to clear soot accumulation from the DPF, EGR and turbo vanes. Another product from the JLM stable, the Diesel Injector Cleaner makes light work of the tough job of cleaning the injectors, again saving fuel and restoring engine power.”
Service
Often when a car is being serviced, the oil is changed. This opens up an opportunity, as Mike observed: “When a technician adds the JLM Engine Oil Flush Pro to the old oil before adding the new, then even old and very dirty engines are cleaned with a corresponding improvement in engine performance and a reduction in fuel consumption.
“Motorists cannott fight the price at the pumps. So, they must trust their technician to keep their vehicle in tip top condition because they also have access to best of breed maintenance and prevention products that will keep workshop bills down. By choosing JLM products, a technician can also increase their revenues with rinse and repeat sales at service, maintenance, and repair. Technicians are also telling us that motorists are now really looking for products they can use between workshop visits to keep their vehicle in good health. They are buying these products from their local garage because of the relationship they have. It takes the guesswork out of standing in front of a shelf of ‘me too’ products and walking away with something that is not up to the task. This of course builds even more sales in the workshop and a healthy additional income.
Stockists
Mike concluded: “It is no coincidence that to date, this year has been our best ever for JLM products and our biggest customers are technicians buying JLM from their local motor factor stockist. Technicians can choose JLM products with confidence because they have heard great things about the brand; They have read about the products in good quality trade publications such as Aftermarket and if they are not presently using JLM products they are open to a conversation and they invariably know a technician who’s a raving fan. Their next step is putting some of JLM’s hero products through their paces. We welcome those conversations.”
For more information, visit: www.jlmlubricants.com
- No fooling: TechMan to team up with E3 Technical from 1 April
TechMan has entered into a new partnership with E3 Technical. Through the new collaboration, from 1 April, existing and new TechMan users will gain access to E3’s database of service schedules, repair times, drawings, procedures, capacities, wiring diagrams fault code diagnosis, and more.
