Erratic Wipers - Is it a CEM fault ?

[rik007]

Hi, I have erratic wipers on my 2006 V70 D5.

I have replaced the stalk, then pcb behind the steering wheel and the wiper motor.

I am now wondering if its a CEM fault?

Do I need to replace the CEM can it be repaired or checked to see if its faulty?

Thanks, Richard.

[Green440wedge]

I recently had erratic wipers as part of a general failing accessories fault. I was advised it was likely to be the Cem, but it turned out to be a faulty ignition switch. In my car's case though the fault coincided with failing electric windows, radio, climate control, indicators, and flashing head lights....

[rik007]

Goodness me that's an odd one to have the ignition switch cause all those faults? Assume you mean barrel where the key goes in?

Hmmm I am suspecting the CEM but quite what to do about it is a bit tricky. Seems a secondhand one is quite a common solution. But then needs reprogramming.

Wonder whether I can get my own CEM tested first?

Also looks like the angle sensor on the steering columns needs replacing! That's been giving an Anti Skid Service Required message for a long time.

R.

[paddy74]

If you already suspect the CEM, you should really get VIDA and a DICE or an error code readout at your dealer. Without fault codes it's throwing parts at your vehicle, in the hope something sticks.

There are numerous members here, that sell complete sets and are very well known for their service. One of them is Cheshired5 (Simon). Send him a PM or check his thread in the "Sales section" of this board.

[rik007]

Hi thanks .... I'll send Cheshired5 a PM.

Fortunately I have a VIDA and have got codes:

CEM-8F2C Wiper signal too high
CEM-8F2D Wiper signal too low
CEM-8F21 Windshield wipers faulty signal

and a few others ... but these seem to point toward the issue I'm struggling to solve.


Many thanks Richard.

[cheshired5]

Originally Posted by rik007

CEM-8F2C Wiper signal too high
CEM-8F2D Wiper signal too low
CEM-8F21 Windshield wipers faulty signal

Based only on these codes you've provided, click on the fault codes and View Information and you'll see the description for all of the above.
Everything points towards wiring for the wiper motor, SWM to CEM connection or the rain sensor wiring.

I only supply diagnostic tools and Vida.
I don't know anything about CEM repair but nothing is suggesting a certain CEM fault based on what you've told us so far.

[rik007]

Thanks for the above help Cheshired5 .... will have a look.

Richard

[IC]

Hi, I had the intermittent wipers on contantly on my V70 when the engine was running. An auto electrician and I spent hours trying to trace the fault. Step by step we traced where the fault could be checking relays/fuses in fuse box in engine and CEM. Took wiper stalk off/further dis-assembled the steering wheel and traced the fault to a loose connection in from what I can remember the steering wheel control module?

The fault codes were CEM 8F25 relay windshield wiper signal too low and CEM 8F relay windshield wiper high speed signal missing.


We only solved the issue after putting everything back together and realised that it was just a loose connection somewhere in the steering wheel! You will have an airbag warning if you do work on the wheel - I had an auto electrician do the work - you do need to be cautious working near the air bag in case it does go off using the appropriate procedures and be able to clear the air bag code.

[rik007]

That is very helpful indeed ... it does seem like a loose wire to me. As occasionally the high speed wipers start up, then will stop randomly. If I wait long enough they will do it again but with no regular pattern to when they might come on.

All help has been really appreciated from all posts so far, I am very keen to solve the problem as its a great car returning great MPG and a joy on long haul drives. It would be a shame to let it go if I can get the fault sorted.

Thanks also for the advice on the air bag. I am nervous of them for sure. I tend to leave the battery disconnected for a minimum of 10mins before tampering anywhere near the air bag. I believe that is about enough time to let the electronics discharge ... but even so I guess the slightest signal and it could go bang.

Will keep this thread posted re progress...

Rich

[rik007]

Checked the wiring under the steering wheel and sockets ... but cant find anything.

So its time to take out the CEM and see what is going on there.... oh the joy!

Does anyone know of a decent company who can check the CEM??

Thanks,

Rich