Quote:
Originally Posted by maciejzi
Hi everyone,
I have a problem with my lovely XC90. When driving on a straight road suddenly I felt a jerk and saw error messages on the dash panel urging me for gearbox service. My mechanic diagnosed lack of charging voltage and replaced alternator and the battery.
There are still some problems though.
The lights on the gear lever are off. There is no indication of the current gear on the dash panel. "Gear selector service required" displays on the dash panel.
There are also some error codes in the system:
DDM-0030 Rear view mirror potentiometer Faulty signal
DDM-0032 Rear view mirror potentiometer Faulty signal
TCM-P086013 Gear Shift Module A communication Circuit - General Electrical Failure - Circuit open
CEM-3F03 Shift lock signal Signal too low
BCM-C111768 Stability function - Algorithm Based Failures - Event information
BCM-C006364 Yaw Rate Sensor - Algorithm Based Failures - Signal plausibility failure
BCM-U042862 Invalid Data Received From Steering Angle Sensor Module - Algorithm Based Failures - Signal compare failure
BCM-U041464 Invalid Data Received From Four-Wheel Drive Clutch Control Module - Algorithm Based Failures - Signal plausibility failure
BCM-U042829 Invalid Data Received From Steering Angle Sensor Module – General Signal Failures – Signal signal invalid
BCM-C008216 Brake System Malfunction Indicator - General Electrical Failures – Circuit voltage below threshold
The only symptom for the driver is lack of gear selector console lights and a dash panel error message "Gear Selector Service Required". Apart from that, the car drives fine.
What is causing all these problems? Any ideas? Please let me know
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To have multiple failures suddenly occur at the same time on multiple control units is an extremely unlikely event and would have to be triggered by something common to all units, like:
1. Direct lightening strike to the vehicle causing voltage spikes everywhere and killing power and input/output circuits. You would have noticed this. Highly unlikely.
2. Electromagnetic pulse from eg a nuclear bomb. You would have noticed this too. And I would have read it in the newspapers. Highly unlikely.
3. Bad power supply - you already have a new alternator and a new battery so that can be rulled out UNLESS the you had a power 'surge' (unlikely) which destroyed multiple control units in multiple locations at the same time. Highly unlikely.
4. Bad CAN bus data communication between the units. Use VIDA and check if you can interrogate and talk to each and every control unit.
Other forum members have had issues with one control unit (differential electronic module, DEM, mounted under the car by the rear differential) killing the CAN databus, and thus preventing and disrupting communications with multiple control units.
You need to use VIDA and sound logic to diagnose faults like this.
Apply probabilities: the chances of multiple faults simultaeneously on multiple units is nearly 0, so something must have triggered the event.
Given that you have a bunch of primarily drive related issues, I would get under the vehicle and check all vunerable electrical items, especially gearbox connections and the connections to the DEM on the rear differential. Look for any signs of physical damage from eg a stone or sharp object kicked up by the wheels.
Disconnect the DEM at the DEM itself and see what is reported in VIDA.
Don't just pull a fuse, you need to disconnect the connector.