Looking for some idea for a problem with a 2002 Focus 1.9 TDCI Ghia I bought a few weeks back. It's only done 74000 miles and didn't cost much, but today the ABS and brake lights intermittently light up together. Sometimes for a few seconds, sometimes a few minutes. Sometimes they will be off for 30 minutes, and sometimes they will flash on and off 5-6 times in the space of a few minutes. The brakes work fine and even the ABS does on the couple of times I tested it today. The other thing I've noticed is that the ABS light doesn't illuminate when the ignition is first turned on, nor does it flash on when the ABS is activated upon hard breaking.

I believe both lights being on together indicate a dangerous, catastrophic braking failure, but the brakes appear to be fine. The AA guy I got out to look at it tested everything and couldn't find a fault with it. He also got equal readings from the wheel sensors when he took it for a drive and tested the ABS with hard braking. He believes there is a possible electronic communication issue that isn't effecting the mechanical functions of the ABS.

Any ideas would be appreciated, I really don't want to get rid of the car as it's a lovely drive, but I'm not prepared to spend a whole lot given it's low value. I'm also dubious about driving it at the moment for safety reasons, although as said it drives and brakes fine.

 

This is a known focus MK1.5 problem that is caused by corrosion on the instrument cluster circuit board. The corrosion causes a short circuit between the circuit board tracks which causes the warning lights to illuminate. The ABS and brake system warning lights intermittendly illuminated are usually the first symptoms.

You should remove and disassemble the instrument cluster and look for corrosion on the circuit board. In case of light corrosion it can be removed using a circuit board cleaner or alcohol. After cleaning it is recommended to seal the circuit board using an electronics varnish to prevent the circuit board from corroding. In case of heavy corrosion the instrument cluster will need to be replaced.

Brilliant, thanks. Can I ask, would that also cause the ABS light to not briefly illuminate upon ignition and for the light not to come on when the ABS is activated? 

13 hours ago, JW1982 said:

This is a known focus MK1.5 problem that is caused by corrosion on the instrument cluster circuit board. The corrosion causes a short circuit between the circuit board tracks which causes the warning lights to illuminate. The ABS and brake system warning lights intermittendly illuminated are usually the first symptoms.

You should remove and disassemble the instrument cluster and look for corrosion on the circuit board. In case of light corrosion it can be removed using a circuit board cleaner or alcohol. After cleaning it is recommended to seal the circuit board using an electronics varnish to prevent the circuit board from corroding. In case of heavy corrosion the instrument cluster will need to be replaced.

Just a quick reply to again say thanks for this. I removed the instrument cluster this morning, and once the PCB was removed, saw it had visible corruption on both sides. One quick trip to Maplin and 30 minutes of careful cleaning later, the board and instrument cluster were reinstalled and the ABS light now briefly comes on with the ignition as it should do, which it wasn't doing prior to this clean taking place. I would imagine this will also mean no more intermittent flashing of the brake and ABS lights too.