Tag Archives: code read derby

Citroen Berlingo with ABS Wiring Fault.

A 2014 Citroen Berlingo came in to us with an ABS fault to be looked at.

First thing to do was carry out a diagnostic code read to see why the ABS light was on, the particular code for this Citroen Berlingo van related to an open circuit on the rear left wheel speed sensor.

We checked the actual wheel speed sensor for a fault but it checked out ok, next job was to check the wiring from the sensor back to the ABS pump.

Most of the wiring for the rear ABS sensors is hard to access as it runs inside the van. once we had determined that there was in fact a break in the wiring from the left rear sensor and the ABS pump (by checking continuity of the wires) it was time to start stripping the interior and physically check the wiring for a break.

After removing the passenger seats and lifting the carpets to access the wiring we noticed part of the raised carpet flooring had been trapping the ABS wiring loom between a raiser and the body and over time had rubbed through the wiring and caused it to short out against the body.

ABS wiring trapped under the carpet.

We repaired the wiring and and rechecked for continuity through the loom which we now had. Time to clear the stored fault codes and check for a wheel speed signal using the live data on our diagnostic scanner, perfect, the signal was good and the same as the rear right wheel, time to rebuild and road test.

Aarons Autos car service garage.

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Broken Catalytic Converter On This Vauxhall Mokka.

A Vauxhall Mokka came into the garage today with its engine management light on in need of some diagnostic work to find out the reason why.

After speaking to the customer we soon found out that we were not the first Garage to look at the Mokka.

It had gone into another garage who had replaced the ignition coil pack due to diagnostic trouble codes relating to cylinder miss fires, the coil pack cured the problem and the customer left happy.

After a couple of days the engine management light came on again so back to the Garage she went.

This time the diagnostic codes related to Oxygen sensor (lambda) faults? But rather than checking live data on the scan tool or checking the sensors with an oscilloscope they proceeded to change the sensors and clearing the fault codes to turn off the engine management light.

After another couple of days the light came on again but rather than take the car back to the same garage the customer looked on Google and found us, gave us a call and got herself booked in.

Once the car was in our workshop we plugged in our Diagnostic scanner and carried out a full code scan of the vehicle, all modules were clear of codes except for the Engine Control Module (ECM) which had codes relating to ‘Oxygen sensor faults’.

We then carried out some live data testing on the Oxygen sensors to see what was happening, straight away we could see a problem, both Oxygen sensors were reading the same, this is not good!

Both Oxygen sensors showing the same pattern.

The basics of Oxygen sensors are that they read the gases which are being produced by the engine before and after the Catalytic Converter, and if the Catalytic Converter is working correctly the first sensor should be switching and the second sensor should be pretty static (on idle), if this is happening then the gases coming out of the Cat are cleaner than the gases going in to the Cat meaning lower carbon emissions.

Basics of the Oxygen Sensor.

Once we had checked the Oxygen sensors were working properly (not giving false readings) we needed to check the Cat’s internals to see why it wasn’t working.

With the Cat removed it was obvious why we were getting the same readings on our live data, the honey comb centre of the Catalytic Converter which catches and burns off the carbon from the engine had broken up and was allowing the gasses to pass by.

The Catalytic Converter had broken inside.

A new Cat was fitted and we ran another scan, this time no codes returned and the Oxygen sensors were working as they should.

Both Oxygen Sensors now reading as they should.

The customer now has a car which is working as it should, more economical and with a lower carbon output.

Aarons Autos car service garage.

Your friendly car garage in Derby

Give us a call at Aarons Autos for more info.

Mini Cooper S Timing Chain Fault.

We had a Mini cooper S come into us with several fault codes in its ECU (engine control module) relating to different faults and had no boost pressure until high revs when being driven.

Once we had cleared the codes and ran the car up to read some live data it was quite puzzling! we were still getting codes relating to boost pressure control, yet everything we checked seemed to be working as it should.

We checked boost pressure sensors, MAP sensors, MAF sensors, turbo actuator, boost pipes but we couldn’t find a fault with anything. After spending couple of hours checking all these items we decided we needed to check the timing of the engine which meant removing the rocker cover to allow access to the camshafts.

Once we removed the rocker cover we noticed something strange, the top timing chain guide was missing! the mounting bracket was still in place but the guide itself was missing.

Chain Guide Broken Away From Bracket.

On further inspection we noticed that the missing guide had broken off and dropped down in-between the timing chain cover and engine. we removed the broken guide and carried on with checking the engine timing.

When we fitted the engine timing tools we could see that the inlet camshaft was at least one tooth out of alignment. As we started to strip the engine to remove the timing chain and guides we noticed that as the top guide had been rattling around inside the timing chain cover it had caused damage to the other guides!

We removed the sump to check for any other debris from the damaged guides and found quite a few bits, one in particular had managed to wedge itself inside the oil pick up, luckily the gauze filter had stopped it being picked up and thrown around the internals of the engine.

Debis In The Oil Pick Up.

After removing all the debris we fitted a new timing chain kit including new guides and a new tensioner, rebuilt the engine using new gaskets and seals where required and making sure that the engine timing was now correct.

Now that the engine was ready for testing we made sure all codes were cleared from the ECU and started the engine, so far so good, no codes had returned and the engine sounded a lot smoother.

Time for a road test to see if we had cured the boosting problem, the car drove faultlessly and had full boost from the off.

This just goes to show that you can’t rely on fault codes alone, the codes in this car had us chasing our tale for while until we decided to go back to the start and check basics.

What we presume had happened in this case is that the chain guide had broken dropping on top of the crank gear and jamming it enough to allow the chain to jump a tooth which in turn meant the engine timing was out causing our running fault.

Aarons Autos car service garage.

Your friendly car garage in Derby

Give us a call at Aarons Autos for more info.