BMW Shows Warning Lights

Service and Repair Date: September 2015

A BMW 735 LI e66 came in to us for warning lights on the instrument cluster. These warning lights would include airbag, check engine, traction control. The wipers weren’t working and indicators were not cancelling.

When we scanned the car it had numerous faults which we presented to the owner and said that would be multiple system failure and we’d need to work through each system and each fault code one by one to rectify these faults.

The owner said he knows what the faults are he’s been to another workshop and passed me a box of components that had been replaced but didn’t fix it.

BMW SZL Steering Column Switch

First fault we wanted to look at is the SZL steering column switch with steering angle sensor which was replaced with a second hand part. When we check the part number the SZL, which is unique only for BMW, looked identical however their part number doesn’t match the vehicle. We had no choice but ordered a brand new SZL fitted to the vehicle and programmed it which fixed some of the warning lights (the second hand SZL and the labor from the other workshop that was spent is down the drain!).

Airbag Model Replacement Mismatch

Second fault we investigated was airbag fault. It had two fault codes for the driver’s satellite seat and the driver’s door satellite message. Then we found out the previous workshop went as far as buying a second hand seat from the wreckers to replace the seat occupancy sensor between the two seats which did not work. When we removed the original seat we found the seat occupancy sensor was in a complete different shape and was not applicable to the model. (Second hand seat and labour from the other workshop down the drain). They actually sent the two seats to the upholsterer/trimmer to have the leather removed in order to get to the sensor for replacement! Something we would do in house anyways because we know how to do it no need to send to trimmer. We replaced the seat occupancy sensor with a brand new one coded and programmed and that fixed another fault code.

Missing Gasket

Next fault code was the driver door satellite which is essentially a pressure switch that ignite the door airbag and it works on fiber optic. The fault was a no message from the door satellite. After testing procedures we replaced a fiber optic line with a new one that fixed this problem however on removal of the satellite we found there was a gasket missing. This gasket is crucial to the operation of the satellite and after all it is a safety system for the vehicle. So that fixed the air bag prob. The more of the story so far the owner he was saving himself by using second hand part and taking it to the repairer who didn’t know these system in fact it costs thousands more to repair correctly.

How We Fixed the Root Cause of the Wiper Module Issue

Last thing was wipers were not working at all. We had a fault code of no communication with wiper module. The wiper module is essentially the motor and all the linkages attached to the motor themselves. but for $2k we need to confirm this is the fault and nothing else. So looking through the wiring diagram we can see that from the wiper switch that sends a signal to 3 other control modules before it reaches the wiper module. So we wanted to make sure none of those three control modules were at fault. After 1 hour of test procedures we were able to confirm it was the wiper module at fault. We confidently ordered the module for replacement.

European Car Specialist who Decipher Your BMW

Why we call ourselves specialist we are able to find out exactly how each particular system works and be able to decipher BMW wiring diagrams and test procedures to confirm faults of the individual components and not just replace a part and hope for the best.

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