Case studies

Intermittent non-start
The car came in with an intermittent non-start complaint, but after quizzing the customer it became more of a “no crank” problem

High idle speed and cutting out
The vehicle came in with a complaint of high idling and occasional cutting out.

Troubleshooting a knock sensor
The vehicle arrived with the engine MIL on but with no noticeable running problem. Checking the system with a scan tool, I found these diagnostic messages: Accelerator potentiometer, Knock sensor Cyl 1-2-7-8

Intermittent misfire
The vehicle had an intermittent misfire and the engine MIL was on. I found the engine misfiring constantly, with excessive smoke issuing from the tailpipe, so I left it running for a little while to get a feel of the problem and to scan the system for trouble codes.

Intermittent misfire
When the book-in came, I allocated more time than usual to this one...

Heavy steering
I’d visited this 2002 Audi A2 once before with an intermittent problem of the power steering going heavy. During testing I couldn’t get the car to fail, and checking the system with the scan tool found no DTCs logged either.

CAN Bus Fault
A 2001 Audi TT Quattro arrived in the workshop with a complaint from the customer of an intermittent ESP light. At first the fault was not obvious at all. We had heard that the ABS modules could be a common failure but I had to be sure before fitting.

Cylinder misfire
An intermittent issue of the engine warning light illuminating and fault code “P0302 Cylinder 2 misfire” detected.

Low speed ABS fault
The vehicle came in with the complaint that the ABS could be felt working through the brake pedal at very low speeds. I carried out a short road test to verify the complaint and, sure enough, the ABS would cut in at very low speeds; in fact, just before the car came to a stop.

Scan tool communication fault
The car had an intermittent drivability complaint, bogging down under acceleration with no MIL flagging. The customer insisted that it wasn’t just intermittent; it was very intermittent.

Poor interior temperature control
The customer complained that the interior temperature would occasionally hang at one setting. He couldn’t say at which temperature this happened, just that sometimes it stopped working. I decided to investigate.

Cranking with no start
This car was a 1999 Ford Escort 4 cylinder 1.6 litre and had been bought from a reputable used car lot with no apparent problem. After a few weeks the car had an additional inventory of lowered springs, alloys, up-rated stereo, and two big holes in the rear parcel shelf ready for some speakers.

Surging at idle and poor running
This customer reported bad surging at idle when the vehicle was warm, general poor running, and repeat DTC logging of LH BANK FRONT O2 SENSOR and RH BANK FRONT O2 SENSOR.

Non-starter
This vehicle had found its way to a specialist diesel shop with a no-start complaint. The car began by occasionally cutting out, but progressively got worse and eventually turned into a complete no-start.

Misfire under load
This Vauxhall Astra 1.6 had a misfire problem under load. The repair shop had diagnosed the coil pack as faulty and fitted a new unit with plugs, but this made no difference to the problem.

EGR valve
The customer complaint was intermittent cutting out. This was eventually narrowed down to only stalling at junctions: how important is correct information?

Non-starter
This 2004 Corsa 1.2 arrived with dash and engine auxiliaries already stripped and its trims and covers in the boot. In fact the ECM was missing and had to be sourced from the previous repairer; so a good start.

Battery drain
This BMW had a complaint of intermittent no start caused by the vehicle battery discharging. Sometimes it would last two weeks and other times only last two days. The battery had already been replaced, twice, and the alternator overhauled and given a clean bill of health.

Intermittent speedometer
The case was a 1999 Fiat Bravo 1.6L with a complaint of intermittent speedo operation. The speedo would read correctly up to cruise speeds then would suddenly drop to almost zero.

Electronic Control Module (ECM) failure
This Fiat Punto 1.2Lsuddenly developed a misfire and never recovered. It was driven to the customer’s own local garage, where they carried out the usual checks, and was starting to look like the ECM had failed.

Misfire
This Peugeot 406 came to me with a complaint of misfire, and had with it one of the most comprehensive shopping lists I’d seen...

Poor starting
The vehicle was a Fiat Ducato 2004 2.8 JTD with a repetitive complaint of poor starting. The engine would crank at good speed but took a while before it eventually fired, and once started the vehicle drove fine.

V6 Transplant
Ordinarily I wouldn’t have given this the time of day had it not been for an unusual recorded trace, which I felt would be interesting to share. The eventual cause of the fault was… you’ll have to see it to believe it.

Variable nozzle turbine pressure control
I was fortunate enough recently to get hold of a WPS500X Pressure Transducer and looked forward to using it right away. It didn’t take long before I found a perfect excuse to switch it on: the Variable Nozzle Turbine (VNT) boost control.

Diesel engine rebuild testing
The Michigan Army National Guard operates and maintains a very large fleet of heavy diesel equipment. It is imperative that this fleet be kept at a high level of readiness and reliability at all times.

Intermittent and progressive failure to start
The car was brought to us on the back of a tow truck, the owner reported that after running faultlessly for some four months after a new distributor had been fitted, one morning, for no obvious reason, the car would not start.

Misleading MIL
The vehicle arrived at the workshop because the MIL (Malfunction Indicator Lamp) was illuminated. The vehicle showed no other drivability issues.

Misfire
This VW Golf (1.8, 20 valve, turbo, engine code AGU) was presented to me with the fault described as a misfire at 2000 rpm.

Braking fault
A 2000 model year BMW 5 Series was brought to us with the ABS/ESP light illuminated, following unsuccessful diagnosis and repair elsewhere.

Misfire
A 2003 Vauxhall Signum arrived at the workshop with a slight misfire and general flatness under acceleration. A scan provided the code P0301 (Cylinder 1 Misfire Detected) and a quick inspection confirmed that the insulation had failed on the cylinder 1 coil area.

System too lean
A 2002 Toyota Avensis came in with the MIL on and two DTCs present: P0171 and P0174 System Too Lean on banks 1 and 2 respectively. On the first visit I was asked to clear the codes (it was a motor trader’s car!) which I did, with the suggestion that it would most likely return.

Hard to start from cold
I had a 2003 Ford Focus 1800 TDCI Duratorq come in with a hard start issue from cold. Once it was warm it would start great every time. No DTCs stored and live data showing good pressure generation.

Battery discharge
Recently I was faced with a customer who had completely given up on the idea of her car ever being fixed. The lady owner of a 2001 Audi A6 1.8 Turbo, explained to me how she has always had problems with the battery discharging.

Misfire
This story concerns an employee of Pico Technology and their journey to the office. About one mile from work the owner of this 54,000 mile Smart Fortwo started to experience a very noticeable misfire.

Catalytic converter
Recently I had a 2003 Dodge Ram 4.7 litre V8 booked in with the MIL reporting a problem. With only OBD connectivity I managed to pull P0420 catalyst efficiency bank 1.

Crankshaft reluctor
This vehicle was recovered from another garage after having its engine rebuilt. It would start and then cut out.

Injector fault
A 2003 Audi A8 was having a problem with rough running which in turn was causing the engine management light to illuminate.

Low Power P0191 P1138 MIL
Intermittent faults are the bane of our lives in the garage. Recently though we were fortunate to have the scope set up whilst a problematic Peugeot faltered before our eyes, thankfully the scope was gathering data.

Electrohydraulic gearbox control
Knowing when to say “No!” is something that we learn as we progress through the ranks in the motor repair business, but sometimes we still succumb to the urge to take on an interesting job. We recently had a 2003 BMW M3 drop in on us, with two warning lights displayed and the customer complaining that he kept losing his gears.

Intermittent misfire
The Mercedes W140 S-Class V8 engine had developed an intermittent misfiring fault. The misfiring could be observed during idle speed when the engine was warm – however it was not a serious issue. Within a month it became apparent that as the engine coolant temperature reached 60 °C, the ‘intermittent’ fault became permanent.

Rough idle
In July of 2010, a 2001 Audi S3 came to us with idling problems. To our disadvantage, a garage had previously worked on the vehicle and cleared the ‘DTC’ (Diagnostic Trouble Code) information from the ECU.

Intermittent misfire
This is the tale of a 2002 Ford Explorer with an idle quality complaint. According to the customer the idle would surge, especially when first started and would even stutter a bit when put into gear. As the engine warms up, the problem fades and is much less noticeable.

Intermittent non-start
A Proton Impian was suffering from intermittent starting problems, and the vehicle randomly cut out. This caused the engine warning light to illuminate.

Non-starter
The vehicle had been driven through a flooded area, and water had entered the block via the air intake. The car cut out with the engine flooded with water. The cold water entered the hot cylinder block, and caused it to crack due to thermal shock. The engine had been replaced, but could not be started.

Misfire
Technician and workshop owner Rich Barton of Iowa, USA, was shown a 1996 Ford Windstar minivan that ran well when cold, but misfired badly when warmed–up.

Misfire
This Chrysler Concord (coil over plug system) came in with a cylinder–specific misfire problem. With some testing I found that the number 5 coil had no spark.

Cold start problem
This car had a cold start problem, where the engine ran poorly and white smoke was apparent. The previous engineer had changed injectors and the actual engine head, however the problem still occurred.

Engine cutting out
The car came to us from a transmission repair center. The problem was an occasional engine cut–out during cold cranking. It is difficult for technicians to investigate this particular problem due to it occurring during cold cranking.

Rough running
The car came to me after the previous repairer had spent a week or so head–scratching and internet–searching.

Misfire
When cold starting this car would misfire, but when warm it quickly cleared. No misfires occurred under normal driving conditions.

Faulty air mass sensor
Strange engine behaviour between 1200 rpm and 3000 rpm. There was a little bit of engine knocking and some misfire — with black smoke coming out of the exhaust pipe. The engine had a fluctuating idle rpm — sometimes worse than others.

K–Bus diagnostics
The vehicle was left with me and I was able to put a diagnostic plan in place. The vehicle started and drove fine, the TPMS is a manual reset function and would not reset.

Surging at idle
Engine generally idled okay until it was shifted out of Park, and then it started surging. Going back into Park did not return to a better idle and continued to surge.

Rover 45 with MIL on, P0170 Fault Code
This car came with the MIL (Malfunction Indicator Lamp) illuminated but no reports of any running issues. The first action was to read the PCM (powertrain control module) for the stored code(s). There was only one stored.

Poor performance
I was presented with this 1991 6cyl E36 325i BMW which had an on-going problem for the last two years and it seemed repairable. The complaint was lack of power, hesitation and the occasional cutting out on acceleration once warm.

Sudden power loss
I admit that the fix is probably quite obvious using the parts darts technique or best guess scenario, but I thought this particular job demonstrated the use of the WPS500 as an everyday aid to speed up the diagnostic process.

Unstable idle speed
The vehicle in question was a 3.8 E-type straight 6 cylinder. Our customers concern was unstable idle speed, reluctance to rev, and horrendous backfiring with hesitation at wide open throttle (WOT [the default position for E-type drivers]).

Cylinder misfire
I had a customer's 2007 JEEP Compass , European Spec, fitted with the VW 2.0l TDi PD engine (code BLY). Unfortunately standard VAG software (e.g. VCDS) cannot communicate with this ECU (due to it being a JEEP).

Noise, Vibration and Harshness
A MK5 VW Golf 2.0 TDI with a distinct vibration throughout the cabin at a very specific road speed range of 67- 73 mph, presented a real nuisance at cruising speed. This problem resulted in the customer driving at 65 or 75 mph to avoid the vibration.

EBS braking fault
The customer complained of an EBS braking fault which occurred intermittently. When the fault occurred then the EBS light would illuminate on the display and the EBS function would revert to conventional braking.

Non-starter
Bought at auction. When viewed it was a non-runner, at the actual auction it ran! Numerous warning lights flashing, engine start and stalling, severe engine rattle under brief running conditions and excessive smoke via the exhaust. So where do you start? It has to be the beginning.

Lack of power, poor cold start
If at first you don't succeed...you know the rest. This case study follows post- purchase rectification of a 2007 VW Caddy 1.9 TDI (Engine code BLS). The Caddy was purchased at auction during the summer with the knowledge that the vehicle was not running at its best, but was "running"!

Poor running
The case study below demonstrates how PicoScope fits within the diagnostic jigsaw when resolving seemingly complex issues. The analogy of a jigsaw fits well if we look at the essential pieces required for a successful diagnosis.

Charging system communication error
Here is one vehicle that has been suffering from repeated breakdowns as a result of what proved to be overvoltage.

Loss of power P1251
The Pico Journey forms a typical yet simple example of how PicoScope sits alongside any scan tool on the road to a successful diagnosis.

NVH Cabin Vibration
The trouble with vibrations is that we all interpret them differently (which is why we should measure and not guess), but with this vehicle you could not deny a considerable vibration throughout the vehicle in a very specific engine speed range. Starting at 1450 rpm through to 1700 rpm the vibration was evident, with peak vibration occurring around 1600 rpm.

Misfire
The topic of this case study is not so much "How we managed to diagnose the fault in question" but more about the multiple options at our disposal when it comes to diagnosing component failure.

Misleading fault codes
When it comes to diagnosis a cool head must be maintained when all around appears to be crumbling. Our relationship with the customer pays dividends during diagnosis where rapport is essential when things appear to go from bad to worse. It is very easy to jump to conclusions when the evidence gathered during diagnosis points to a particular component. It is at this stage we should take stock and step away to ponder before we commit to our diagnosis.

Renault Clio Fuel Pressure problem
This 2009 (MK3) Renault Clio 1.5 dCi engine had a complaint just after starting where a strange noise occurred for a few seconds followed by the MIL illuminating and the engine entering recovery mode.

Severe hesitation
During hard acceleration, the vehicle violently surges back and forth. When the accelerator pedal is released, the vehicle resumes normal driving performance. The symptom is evident regardless of engine temperature, and is present whenever the driver attempts hard acceleration (the symptom is permanent).

Juddering at low speed
Driving at low speed the vehicle appears to judder, accompanied with a yellow warning light illuminated within the instrument panel. The symptom was evident every drive regardless of temperature and road condition, and had been evident for over a week.

Jaguar X-type with severe power loss
Engine warning light became illuminated, accompanied with severe lack of power under acceleration after changing gear or when pulling away from rest (evident for approximately 3 weeks).

Faulty Throttle Unit
Once a week the vehicle’s injection warning light illuminated and the vehicle entered limp home mode. Switching the engine on and off cleared the warning light and the vehicle seemed fine for another week.

Subaru with incorrect ABS operation
There is noise/vibration from under the bonnet when driving at low speed over speed humps, accompanied with the ABS warning light.

Engine non-start
The engine is a non-start after a major engine overhaul. Compressions and valve timing have been checked and are correct.

Ford Focus Engine overheating
The engine temperature gauge indicated hot with “steam” creeping from under the bonnet.

Communications fault
Ben Martins was recently presented with a 2015 Mazda 3 with all warning lights on the dash illuminated, accompanied with around 40 DTCs (diagnostic trouble codes).

Hybrid battery cooling system
It goes without saying that Hybrids and electric vehicles (EVs) should be treated with caution when it comes to service, repair and of course, diagnostics. We should not be fearful of such technology, though, once we understand the safety procedures involved and the operation of the system we wish to diagnose.

Camshaft code on Mazda
This is a story about the power of using a scope and how Northside Master Auto Tech went about to diagnose a problem on a 2006 Mazda BT 50 Diesel

Finding faulty engine mounts with the NVH Diagnostics Kit
My 1996 Rover 100 helped me get to grips with NVH. The first test I did was in the passenger compartment with the accelerometer on the inner seat rail. I was a bit surprised by the magnitude of the engine second-order (E2) peak, but, with no experience to fall back on, I asked Steve Smith at Pico for advice.

EML On and Fault Code P0491
The vehicle in question belongs to a staff member here at the Pico Head Office. The driver informed us that that EML (Engine Management Light) had come on but that there was no loss of power, nor did anything else happen apart from the light coming on.

Scania R480 – Poor idle, misfire, smoke and fault codes
I was recently asked to take a look at a 12.3 litre HGV. With this particular lorry, a slight misfire was evident at idle, which became progressively worse over time. There were no warning lights on the dashboard, but a strong fuel smell along with smoke and a heavy diesel knock when it was started up from cold; all the characteristics of over-fuelling.

Fiat Kobelco E135 Excavator - Engine shutdown
According to the operator, the machine had always been a little temperamental, but it really started acting up four months ago. The engine would stop suddenly, while the machine was being operated!

ABS and TC warning lights
Upon driving the vehicle at normal road speeds the ABS and traction control (TC) warning lights illuminated. The symptoms were present at every drive, regardless of temperature and road conditions, and had been present for over a week. The warning lights lit upon ignition on and remained on until the ignition was turned off again.

EcoBoost– MAF Sensor
The vehicle was a 2014 B-Max, 1.0L, 3-cylinder, turbocharged petrol engine. It had been brought in as the EML was on with the fault code P0102 Mass Air Flow MAF Circuit Low. I was asked to take look at this new type of air flow sensor that, for now, has only been seen on the Ford EcoBoost engine. The fact that it is a 4-wire type that has a 12 V supply from the same fuse that the fuel pump gets its supply from makes it intriguing.

NVH diagnosis of transmission screech
The vehicle had developed a very loud screeching noise, which sounded like a cross between a squealing drive belt and a loose stack of rapidly vibrating metallic plates. The car was powered by the original GM 16SV OHC transverse-mounted petrol engine and the THM125 automatic transmission and had covered a genuine 52k miles from new.

2014 turbocharger boost
This vehicle came in with the engine malfunction indicator lamp (MIL) illuminated. Using our Xentry diagnostic scanner we found diagnostic trouble code (DTC) P029900 was stored in the engine control module (ECM). Our first step was to find out what condition was required to trigger this fault code.

Brake Booster Failure
When applying the foot-brake, the brake pedal appears hard to press intermittently whereby the customer has to apply more effort in order to bring the vehicle to rest. Upon the next brake pedal use the feel of the brake pedal and the effort required to stop the vehicle returns to normal! The symptom had been very intermittent regardless of temperature/road condition and been evident for over two weeks.

EGR valve failure
The customer reported that there was black smoke coming from the machine, and that when it is running and loaded to the maximum, the engine stalls.

Triumph investigation
We were recently asked to assist with the development, set-up and ultimately the tuning of a rather unique motorcycle. The request turned out to be a fascinating adventure into Motorbikes!

Random misfire
This bus I worked on took a little time to figure out but was very interesting in the end result of what the fix was. The initial complaint on this bus was excessive black smoke on acceleration and the occasional random misfire. So the first thing I did was I checked for codes and no codes.

Parking Brake Failure (EPB)
Questioning of the customer revealed that the electronic parking brake (EPB) on the vehicle occasionally failed to release after being engaged overnight. When the fault occurs, the vehicle can be driven without any brake binding or drag, suggesting the parking brake has released. The symptom had been very intermittent for over 12 months regardless of temperature or driving conditions.

No audio
When attempting to switch the radio on, by using the touch screen interface, the radio button is highlighted but the menu cannot be accessed. The same condition is met when trying to use the command wheel in the center console. No audio or output to any of the speakers including satnav, Bluetooth or voice recognition. Volume also doesn’t work and when adjusting settings for treble, bass, left and right or front and back, the selection can be made but it reverts to the original position after a couple of seconds.

Turbo under-boost and air flow meter drift.
Do you need a scope to diagnose vehicles? Well, it is coming up to the end of 2018 and I’m thinking about all the diagnostic problems I have had this year. I wanted to share the biggest I was involved with (I was helping a dealership).

Faulty piezo Injector
How to test and diagnose piezo injectors without having to send them away? I had the opportunity to try out some new testing methods when I was asked to take a look at a Nissan X-Trail with two fault codes that pointed to all four injectors.

MCU failure
Once again, I find myself standing in a muddy building site. This time looking at a machine with a number of warning faults. The operator could no longer increase the engines RPM in order to move the machine off-site. The machine had 7169 hours on the clock and a 4 HK 5.2 l engine.

Cutting out with no restart
It seems that a lot of the faults I come across these days are communication-based and this vehicle is no different. The complaint this time is: the vehicle suddenly cut out and then wouldn’t restart.

Crank sensor gap
To make a long story short, $2,200 later and with a replaced crank sensor, new knock sensors, a tune up, new wires to the crank sensor to eliminate bad wiring faults, etc, it was still not fixed. I’ve been trying to work on my diagnostics skills, so my tech took it on for me to have a challenge to work on.

Camshaft correlation error (Quad Cam engine)
I am sure many of us have experienced the limitation of only having four PicoScope channels while being deep in the battle of diagnosis. Diagnosis commands that all variables are kept to a minimum, and from my perspective, there have been numerous occasions when six channels would have been perfect. Luckily, we now have an 8-channel Automotive PicoScope, and it was incredibly useful in this case study.

DAF rear steering fault
I was asked by a customer if I was interested in taking a look at problem dust cart. The owners, in the attempt to get a silver bullet fix, requested a part replacement based on limited diagnosis. The part was reluctantly replaced by our customer but, as you’ve probably already guessed, it didn’t fix the problem. We were determined to do it properly, to find the fault, prove it and then verify the fix with PicoScope.

Misfire and MIL concern
Mario Rojas has written this case study where he looks at a misfire and MIL concern on a Chevrolet Suburban.

Driveline vibration problem
My customer bought the car 6 months previously. During the initial test drive, he noticed a slight driveline vibration. The salesman told him it came from the tires. The car got four new tires matched with rims, balanced and road force tested. But the car still had a driveline vibration.

Lack of power
This vehicle came in with a customer complaint of lack of power; customer’s own words, “feels like it has no boost” and the CEL was illuminated. Using the Xentry diagnostic tool we found two fault codes stored.We were not able to obtain any specific information on the criteria for setting these fault codes. We reviewed the freeze frame data and it was unhelpful at identifying the conditions that the fault was set under.

Lack of digging power
This isn’t the most in-depth diagnosis on this machine, but we used PicoScope to record each step of the diagnostic process to verify the fix.The machine I came to look at was relatively old with plenty of hours on it and it had had a bit of a tough life. The customer’s complaint about this machine was that it was down on digging power.

Fuel Pressure Fault
I know there are a few of you out there that are interested in using the PicoScope on trucks so I thought I'd share my process in this case study. I have done a few of these now and Pico has definitely improved the accuracy and speed of the diagnosis.

Cabin vibration at motorway speeds
The customer reports that vibration can be felt through the vehicle at approximately 75 mph. The symptom has been present for over 2.5 years, and they have had numerous attempts to resolve the issue.

Lack of power - diagnostic process
Have you ever been in the position where a customer calls up to say ‘the machine is down on power and we think it’s the hydraulic pumps so can you replace them?’ You respond by saying ‘of course but wouldn’t you rather we look at it first?’ ‘No, just price it up, it needs to be fixed.’

Knocking noise from steering column
We look at a known and documented issue surrounding a knocking noise from the steering column area of a BMW that can be heard inside the cabin. The issue was solved at the Check for Technical Bulletins (Recalls & Campaigns...) stage of the diagnostic process. However, this is a great opportunity to demonstrate how to objectively locate intermittent knocking noises, which are time-consuming and potentially expensive to diagnose.

A telehandler with a slow winch - part 1
We’re about to follow a journey where it, in total, took nearly a year to find the solution. I had a phone call about visiting a Manitou Telehandler. The customer reported that the winch accessory was slower than that of other machines. Several other people had already taken a look at this machine but my plan was to get a more detailed understanding of the fault with the PicoScope and hopefully be able to pinpoint the problem to the customer.

A telehandler with a slow winch – part 2
We’re continuing the journey following Ben's work on the telehandler with the slow winch. Will they be able to find the problem?

Misfire
This one is a short case study, but it shows that with the right steps, you will find the task easier. The customer complained of poor performance and vibration which feels like a misfire. There were no warning lights on the dashboard.

Warning message “STOP: Electric failure DANGER”
Technology is changing at a relentless pace, presenting challenges to technicians worldwide. For those who are not brand-specific, diagnosing anything and everything, these challenges are beyond consuming. The following case study is one such example. I would like to share the hurdles I had to be overcome when I attempted to diagnose a Renault Zoe with virtually zero product knowledge. Throw into the mix an “All Electric Drive Train” and you just know you are going to reach that point during the diagnosis where you ask yourself why.

Kangoo EV charging fault
With the growing number of EV vehicles on the road, it is tough keeping up with new technology. The increase of EVs has led to a number of the typical internal combustion engine issues being eliminated, with some manufacturers stating servicing is optional. All that aside, EVs are not without faults. In our previous case study, Steve took us through how important the 12V system is to an electrified vehicle. This time around, we will take a look at a Renault Kangoo with a charging issue and the hurdles that diagnosing this type of fault brings.

Warning lights and limp-home mode Part 1
In this ever-changing world, there is one constant in our trade: cars will break down. As we try to build our knowledge and the level of complexity increases, there are always things that can trip you up. This particular case was no exception, with twists and turns all the way!

Warning lights and limp-home mode Part 2
This is part 2 in Ben's case study about the Mercedes E300 Hybrid with multiple warning lights.

Engine warning light illuminated: Engine misfires from cold
While the electric vehicle revolution marches relentlessly on, fuel-efficient internal combustion engines will have a place in future powertrains for years to come, either as the sole power source or a range extender for electric drivetrains. The challenge of squeezing every last drop of energy out of each gallon of fuel pushes both engineering and engine management to another level.

Does not switch to Ready mode and drivetrain error message
While the future may be Electric, and technology marches on at a relentless pace, the following case study highlights a typical fault we have seen on numerous vehicles for many years. It is as relevant today as it was all those years ago.

Engine rattle at idle speed
While the future may be “Electric” the internal combustion engine (ICE) has many years left before it disappears forever. However, I am certain that it never will. Looking at the current legislation, 2030 will see conventional petrol and diesel cars/vans banned from sale with an extension to plug-in hybrids until 2035. (Used cars will be unaffected by the ban). If we do the maths on the above, the ICE will continue to be present in various vehicles up to 2035 along with a multitude of vehicles going back to 1886. Needless to say, that is a lot of engines with potential for diagnosis and failure. The following case study looks at the application of PicoScope and the NVH software when tackling a typical engine noise and consequential failure.

Engine hunting under load
You’d have thought that when faced with construction equipment, the smaller the engine the easier it would be to work on. That couldn’t be further from the truth! A smaller machine typically means it’s more difficult to work on. This little 14T Komatsu was no exception as we were to discover.

Intermittent non-start
The challenges we face when doing a diagnosis do not only require investment in test equipment, training and hours of ongoing study. We also need to manage the diagnostic task at hand. The following case study is one such example, where the costs of the diagnosis and the parts required exceed the value of the car, yet the drive and ambition to discover “what was wrong” dominated over our better judgment.

Severe vibration under acceleration
NVH diagnostics requires a methodical approach and evaluation of test results to reach a conclusion that is satisfactory for all parties involved. The case study below describes the rapid identification of a customer’s complaint of vibration and how using multiple sensors (either microphones or accelerometers) become invaluable in locating the source of the problem.

Non-intrusive engine evaluation
A recent visit with a Volvo XC90 with a permanent misfire problem provided a great opportunity for a non-intrusive engine condition evaluation. How we tackle such symptoms of misfire is predominately governed by experience, probability and accessibility. By doing a non-intrusive engine evaluation, you can provide a cost-effective initial diagnosis and deliver conclusive evidence on how to proceed with rectification.

Wheel loader with loss of communication
A Case wheel loader with 13 127 hours on the clock and a communication problem. Ben went to the seafront to help diagnose the issues on this machine. It had been suffering from an intermittent problem for weeks with no obvious way to reproduce the fault.

Fails to charge via plug-in charger
While electric vehicles appear to be the future, plug-in hybrid vehicles seem to be the order of the day when it comes to the best of both worlds. Such vehicles can drive on pure electricity, meeting the current low emission regulations for cities, yet, with old faithful on-board – the internal combustion engine, we can take advantage of seamless mileage without suffering range anxiety. (What’s not to like?) Both power sources have their distinct pros and cons but somehow, when you combine the two, you have a formidable vehicle that ticks almost every box. The following case study focuses on the plug-in high-voltage (HV) charging system of a hybrid vehicle and the challenges encountered along the way.

Komatsu PC210 LC AdBlue fault
The following adventure started with a back story where the machine had been looked at previously and parts had been replaced. I had a quick chat with the operator who reported that after the second time it was looked at it worked for around four hours before moving to a level 4 warning where the engine was derated and performance from the machine was seriously downgraded to the point where only a high idle engine speed was possible. The other rather annoying part of a level 4 warning is a constant sounding alarm as soon as the ignition was switched on, with no way of turning it off till the fault was fixed.

Guest case study
This guest case study from Tony Nott, of Michaels Moama Australia, investigates the diagnostic process on a Gleaner Combine Harvester.

Guest case study: Aircon malfunction, no cold air, no DTC.
This guest case study from Rfmotors1, investigates an aircon malfunction.

Guest case study: Pierce Aerial Ladder
Edward Boers was kind enough to share his experience of working on a Pierce Aerial Ladder.

DAF DEF warnings
DAF CF shows multiple warning lights and alarms on the dashboard.

Warning lights, intermittent loss of operation
Warning lights, intermittent loss of operation despite the engine still running. Gears not selectable on ZF Lite AS-Tronic gearbox.

Renault Zoe HVAC
Blockage in AC system causing compressor pressure relief valve to open

Guest case study: Using dual in-cylinder pressure transducers
The team at Autonerdz use a Pico Pressure Sensor Kit to diagnose and fix a 2011 Jeep Cherokee.

BMW Valvetronic
This case study originated on the Pico Automotive forum. Initial diagnostics on a BMW 330e (F30) with an engine warning light illuminated leads into exciting reverse engineering.

JCB JS220 Excavator
JCB JS220 Excavator with a stalling issue.

Misfire Diagnosis on CAT 308E Excavator with Kubota Engine
Relative compression testing on a CAT 308E Excavator with four faulty injectors

Porsche Cayenne misfire DTC and engine warning light mystery
An engine warning light appears suddenly while driving, engine runs at low power until the ignition is switched OFF/ON again.

Using NVH to find origin of engine knock, click, and misfire on a Porsche Cayenne V6
Roman (RFmotors1) uses NVH to run diagnostics on a Porsche Cayenne V6.