BAS Malfunction

[sv4]

I had a malfunction message on my W203 today that says ' BAS Visit Workshop ' while driving. However, there did not seem to be any difference in the car's performance and braking. After switching the car off and re-starting ( the Microsoft way! ), the malfunction turned off and did not reappear after driving.

As my next workshop service visit is not due for some months yet, is this something that I should worry about, or leave it till the next service?

 

[Uky]

There are two possible causes that I can think of:

1. Benz never got to a stage where the software (at least) in the C/SL of 2000+ got completely stable. So they decided that all DTC's (Error codes) that was set was reevaluated the next time the engine was started after a switch off. (Cold "Boot"...) If the system could not find a permanent failure; The DTC is cleared and the light goes off...

DTC's are however stored in the system and can be retrieved using Star Diagnosis. "You will get lists of several pages when doing a stored DTC printout". The failures listed are transient and some of them are caused by things as lost CAN-bus messages (software/hardware glitches) or of course real temporary problems like an combustion disturbance caused by bad fuel.

2. In my case I got "BAS+ESP Failure - Visit Workshop". After calling a friend (Benz-Guru) I got the following information: Simply turn the steering wheel full left, then full right and the steering wheel sensor is recalibrated. This DTC is normally set when doing a turn and the car has lost the sense of where it is going or after the battery has been disconnected, (but then all power windows, and the sunroof position will have to be reinitiated.) I did that, and the "Christmas Tree" in my Instrument Cluster disappeared...

The only DTC's that are not cleared are ABS related ones. If for instance any of the Air-Bag igniter wires are disconnected when ignition is on, a DTC is immedeately set and can only be cleared by the StarDiagnosis unit (£££)

 

[Dieselman]

Possibly you pressed the brake pedal just as the ecu was performing the check. This will bring up BAS fault.
Your brakes will work, just the BAS is shut down.

 

[Robbo]

how old is your battery?

 

[sv4]

Thanks, all. The battery is 2-3 years old, Robbo. Do you think it is a battery related fault? The malfunction message has, not reappeared after several days of hard driving.

 

[Robbo]

If the battery is only 2-3 years old maybe not, but I had the same problems with mine. The battery was changed and the problems have not returned since. When the battery violtage is low, all kinds of random error messages can show up.

 

[sv4]

Thanks, Robbo. Come to think of it, I did leave the car unused for a week or so while on holidays, before getting the fault message. So, it could have well been a voltage drop, but subsequently recharged with usage. Malfunction message has not appeared since, so I'm keeping my fingers crossed.