V50 Electrics : V50 Electrical Problems - Brake Failure

[hughjass]

Hello all,

I posted a while ago about the car going crazy with all sorts of electrical faults including 'brake failure' and 'anti-skid service required' message, with a few fuses blown in the CEM when checking. I've been in the process of looking for a new vehicle but part of me would still like to resolve this issue due to current prices.

The CEM was removed for a few days completely and when reinstalled, the car was given to a garage who said that it broke down when they test drove it and gave it back.

Strangely enough on receiving it, the car simply worked with no problems whatsoever.. for about 135miles of use, when the anti-skid message returned. Where it then disappeared again allowing me to pick it up and bring it home.

Now I have one of the Mongoose JLR clones which works with VIDA. I've linked below the report and screenshots. There seems to be faults everywhere in relation to the BCM, angle-sensor and CEM. I have high doubts all these things can be broken if it can drive fine most of the time.

Under fault tracing when I re-run it, the modules which are orange (not responding?) change. Is this the car or my setup?
Also there is issues with the mileage, the car mileage is *lower* than the mileage where the fault occurred in VIDA. Strange? VIDA says there has been mileage tampering which I seriously doubt as it's only off by a few hundred.

Anything I can try? Is the CEM the brains here and is it that which could be dead and need replacing?

Thanks, if the attachments don't work ill upload elsewhere

[VictorFails]

My V50 came up with brake and anti-skid error messages aparently at random, even shutting down the engine and you could only coast to the kerb. Then after 10 minutes it would start again. Errror codes retrieved by a reliable ex-Volvo agent were inconclusive. Weather was always wet around the days it happend and we had leaky front sunroof drains which resulted in damp carpets from time to time. The CEM isn't far from them and so we thought it was mositure causing intermittent problems. Had the helpful ex-Volvo man clear out the drains so that they run again and dried the carpets thoroughly in recent hot weather and we haven't had a recurrence. Still early days but we are hopeful.

[hughjass]

Originally Posted by VictorFails

My V50 came up with brake and anti-skid error messages aparently at random, even shutting down the engine and you could only coast to the kerb. Then after 10 minutes it would start again. Errror codes retrieved by a reliable ex-Volvo agent were inconclusive. Weather was always wet around the days it happend and we had leaky front sunroof drains which resulted in damp carpets from time to time. The CEM isn't far from them and so we thought it was mositure causing intermittent problems. Had the helpful ex-Volvo man clear out the drains so that they run again and dried the carpets thoroughly in recent hot weather and we haven't had a recurrence. Still early days but we are hopeful.

Yeah, it'll go into limp mode too sometimes. The passenger area has never been wet from what I can recall and the CEM has no signs of corrosion to me. I can always check the drainage things though!

[pinballdave]

A lot of the fault codes are on items on the HS can bus, and the 'signal too high' error on the HS CAN-L suggests that there might be an intermittent short on this connection. So this is where I'd start.

This can be caused by moisture or corrosion in the connectors, but it's impossible to know which connector. So the fault could be on any module connected to the HS CAN bus, either a connection fault, or an internal fault. It could also be caused by compromised insulation on the wiring anywhere in the harness.

There was a recent post by Ashmere, where they found signs of connector pin corrosion on the BCM (the ABS module behind the battery), So it looks like these connector issues can be found in other places, and it may be an idea to check all the connectors.

[hughjass]

I will look up on how to get to the BCM and check that out. Didn't see anything in VIDA though I'm not familiar with it at all.

I did though spend a wee bit of time looking at the massive amounts of information on VIDA and thinking back to various other checks I've done and it seems more unlikely that it could be the entire CEM as the faults are on the HS CAN (which you have said too).

Not sure if this means much but it looks like the BCM lies outside this resistance thing I see in VIDA. And when the car was completely freaking out the resistance was fine. Also the mileage thing is weird to me and I read that could be BCM (/ABS?) related, as both store the mileage or something along those lines. Perhaps wishful thinking and a bit too soon to be sure of that

[hughjass]

So still not been able to take the car up to someone who can get to the BCM. But today went to inflate one of the tyres, and when holding the brake and clutch down when starting the brake failure message returned.

This time it's mostly the ECM complaining (attached).

I don't see anything about the brake pedal this time, as there seems to be a correlation of the brake pedal being pressed and the fault

[Simmy]

open and clean any connections you can get to. with switch cleaner and dry compressed air. codes in the inital state will always show. it dose not mean they are current. disconnect the battery before opening any connectors erase all codes and see which return

[hughjass]

Originally Posted by Simmy

open and clean any connections you can get to. with switch cleaner and dry compressed air. codes in the inital state will always show. it dose not mean they are current. disconnect the battery before opening any connectors erase all codes and see which return

The codes have all appeared since I cleared the previous ones and a electrical fault came back up. wdym by the initial state?

Is it just the CEM and ECM one can relatively simply get to the connectors for, any other modules on the high CAN?

When the CEM was removed and put back in it stopped going crazy and the faults only returned when u pressed the brake pedal or along those lines.

The mileage on the faults being > than the current mileage is weird right? The only repeated fault is to do with the 'Vehicle Dynamics Control Switch'?