TRACS/ABS: Volvo S40 1997 Speedometer not working.

[RBSotirov]

Hi All,

After change of the ABS Module the speedometer stopped working.
The ABS is working fine, no problems at all, the ABS indicator light is on, during the checks for a 2-3 seconds.

The odometer is working. All fuses are fine.
I've removed the car battery for a 15 minutes, but it was not helpful.

The "new" ABS module is from the same Volvo model.

Is there any need of sync between the computer and the new ABS?

Thanks in advance.

Cheers,
Rado

[v40alex]

Which bit exactly have you replaced? The pump or the control unit/both/something else?

The control unit can get corroded inside http://www.volvoforums.org.uk/showthread.php?t=151399, perhaps the replacement was a bad one? The car doesn't need to be sync'd to the new part. Does the speedo start working again if you reinstall the old one?

What was the original fault, why did you replace the module?

[RBSotirov]

Originally Posted by v40alex

Which bit exactly have you replaced? The pump or the control unit/both/something else?

The control unit can get corroded inside http://www.volvoforums.org.uk/showthread.php?t=151399, perhaps the replacement was a bad one? The car doesn't need to be sync'd to the new part. Does the speedo start working again if you reinstall the old one?

What was the original fault, why did you replace the module?

Thanks for the reply.

I've replaced the control unit only, since there was a problem with it and no brake fluid was getting to the front left wheel. That was done by a mechanic.

After that the ABS is working like a charm, however the speedo problem appeared.

As far I know, if there is a problem with the ABS the indicator light will not turn off?

However, I did't bring back the old ABS to test if it works with it.

Thanks in advance.

[v40alex]

The ABS also does a check when the car starts moving, but if you no longer have a light, then obviously that bit of it is now working.

It sounds like the replacement unit is faulty - no speedo is one of the symptons of a bad control unit. Was it a brand new part or used? I think you will have to take it back to the mechanic and explain.

It could be that one of the plug pins isn't seated correctly, you could try inspecting and reconnecting the plug but it's not particularly easy to get to with the brake pipes in the way.

[RBSotirov]

Hi,

2 years later, after going to several car mechanics that were not able to find where the problem is, I got myself Delphi Car Diagnostics.

I found that the wheel sensors were working and forwarding speed signal to the ABS module.

So today I removed the cable coupling from the ABS module and saw that there is rust on one of the plug pins in the cable socket.

After clearing it, it's working fine.

v40alex, thanks for the advises.

Cheers,
Rado