ABS and PSM warning lights

[tonycordon]

I was driving down the M1 yesterday when I heard a 'ping' and the message 'ABS failure, drive to workshop' warning came up, along with the ABS and PSM warning lights. I didn't drive to workshop but did call my specialist. He initially said that ,bizarrely, (his word) this fault could be caused by a faulty alternator! He also said that sometimes the ASB/PMS fault will reset itself after switching off. I switched off and it seems to have 'cured' itself. Has anyone had a similar experience? What was the final outcome?

[thegoose]

If the alternator's ok then either an ABS speed sensor (which the PSM system also requires) is starting to fail or, and I know this sounds odd, the MAF is failing. If the lights are off and you boot it from virtually standstill in first gear and the lights come on as you approach the redline then it's the MAF.

[Never you mind]

I had those come on just after I washed my car. Was told by a local indie that sometimes they get water in them which causes it.

But as above it could be a failing speed sensor.

[tonycordon]

I should have said that I was in my 996 Turbo.

[PR36]

My 987 Cayman is in at the workshop at the moment for this as I put the durametric cable on and the fault code came up as stop light switch which is the brake switch. I replaced the brake switch twice but the fault came back. Reading up it seems these faults can sometimes be tricky to nail down but most common causes are, brake switch, wheel speed sensors, maf, failing battery, or 'faulty wiring'.

[davek_964]

I had that when my maf failed. Think that's the most likely suspect.

[Mark A S]

My 996 t did this a while ago, like above, plugged into the diagnostic thingy and it came up with Fault code 4460, first thing I checked was the plug on the brake light switch above the pedal, it was not on fully, now it is and the warning light has not come on since.

[monthefish]

Could be lots of things, most of them not too serious so don't worry.

As has been said, likely to be the MAF, I think mine was the vacuum pipes leaking (again, 996 turbo)

[Moosh]

stop light switch faulty , very common