C5 2.2HDi 2001 Brake failure message

[Henshaw]

I am getting random occurrences of this message. It is followed by EMS off and ABS fault. It started 3 months ago and is getting more frequent. The message can occur after 7 miles or many more miles after setting out. My local garage used a tester and this pointed to the ABS pump unit. I have taken all the plugs and sockets out getting to the large plug on the control part of the ABS pump, cleaned them all and used contact lube as recommended. The problem still remains. To my mind, the fact that it is random and it doesn't appear until miles after start up and can occur when travelling and not touching brakes points to an electrical weevil. Any ideas as to where to look and is there any other odd area that could cause the fault. I'd hate to remove my ABS pump unit for refurbishment only to find the fault persists and something else causes the problem.

[elma]

Have you checked you're battery? I'm no C5 expert but they do seem to play up on an old battery.

[qprdude]

Battery check, then BSI reset. (Proper procedure for reset is on this forum somewhere) Always worth trying before getting too technical.....and expensive. C5 is a tender beast where electronics are involved. Not sure about the earlier 2.2l cars but the X7 needs a fairly decent battery, otherwise strange things begin to occur, including(but not limited to), many and various error codes being thrown up. Windows refusing to obey commands and other delightful surprises.

[myglaren]

The Battery Disconnect / Reconnect Procedure

[Henshaw]

Done all that and battery is not old. Any other ideas please?

[Henshaw]

I think my brake failure problem might be related to the ESP system, which having read up on it seems very complicated with many sensors) If this system encounters problems, it turns off the ABS system and on my car the first message after braking fault is always ESP failure. (When I had an ABS sensor problem, the ESP was turned off but I didn't get a braking failure message) The ESP system is an optional extra (it was not fitted to my Mk1 SX 2.2HDi) so can this be turned off either temporarily or permanently using a Lexia so the whereabouts of the source of the problem can be determined?