Problems fixed: Mazda, Mercedes and Peugeot

Leading technical supplier Autodata helps you fix three common problems found in passenger cars

The problem

We have a 2013 Mazda CX-5 in the workshop and the customer is complaining the sunroof opens by itself. We’ve carried out some basic checks on the wiring but we haven't found the cause of the fault. We suspect a control module, but we’re uncertain which one it could be.

The fix

The issue you’re experiencing affects all models up to 2nd December 2014. The fault is most likely due to condensation build-up in the sunroof switch causing a short circuit. The sunroof switch is integrated in the front interior lamps assembly. Remove the front interior lamps assembly and discard. Apply felt tape to the sunroof wiring harness and harness multi-plug. Fit a new front interior lamps assembly. This should rectify the fault.

The problem

A customer of ours is complaining that their 2017 Mercedes-Benz GLE Coupe 3.0 diesel stalls while idling. The customer also reported that due to starting issues the battery has been replaced, and we aren’t sure if this is related to the engine stall issue. We found trouble code P06A9 stored in the engine control module fault memory. We have replaced the air filter element as this was partially blocked and the fuel filter as a matter of course, but the fault persists.

The fix

The symptoms you describe are known to affect all models with 642.826 engine code. The cause is likely to be oil contamination of the alternator due to the engine oil filler neck being loose or adrift. Fit a new engine oil filler neck ensuring the engine oil filler neck retaining clips are located correctly. Check operation and condition of the alternator and repair/replace if necessary.

The problem

We’re having trouble diagnosing a fault on a 2018 Peugeot 508. The vehicle came in with numerous warning lamps illuminated and when using diagnostic equipment to check for fault codes, there is a communication error message shown against several control modules.

The fix

There is one fault we know about that affects all RHD models up to 13th November 2019. The fault is caused by the data link connector (DLC) wiring harness chafing on the fascia mounting bracket causing a short circuit. To rectify this fault, remove the fascia panel from below the steering wheel to access the DLC wiring harness. Thoroughly inspect the DLC wiring harness especially in the area near the fascia mounting bracket. Repair the DLC wiring harness as necessary. Fit a protective sleeve to the DLC wiring harness to prevent further chafing. Erase the trouble codes and carry out a road test to confirm the fault has been fixed.

Autodata supplies OEM-sourced technical data and fixes to the automotive aftermarket via its online workshop application.