Mechanics

ABS & TSC ALARM IS ON AND SPEEDOMETER NOT

1998 BMW 540i

Electrical problem
1998 BMW 540i V8 Two Wheel Drive Automatic 117116 miles

I recently replaced the rear right speed sensor when it was giving me ON and OFF alarm on ABS & TSC. This time the alarm is not intermittent but continous, do you think I am having more than one speed sensor failure?

Another problem is the speedometer( XX Km/hr) is not functioning, it stays on Zero. Do you think it is a cable failure?
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Secnew
August 6, 2009.



I have forwarded your question to our BMW tech. He will be with you shortly, thank you for your patience. If the speedo isnt working, nothing else to do with wheel speed will work properly. Have the PCm scanned for codes, then our tech should be able to help you pinpoint the problem

Tiny
Jack42
Aug 8, 2009.
The problem you report may be due to an internal fault in the control module rather than a speed sensor plausibility fault. It is sometimes difficult to diagnose and if found to be at risk, replacement and subsequent coding will be costly, be aware, the fault may be due to several factors, has the car been in an accident? Has there been corrosion or rodent influence that might be hidden? As I said, it could be costly, at the dealer we replaced lots of the DSC control units under warranty, also, it is what generated the road speed signal to the instrument cluster, so when the fault occurs, it could be due to the DSC control module (called a DSC repair kit) There is no cable, it is all electronic, generated by an interpretation of data and sent via bus communication to the cluster.

Dr. Hagerty
Aug 8, 2009.