PSM & ABS warning light problem / advice needed

[S99]

On my Boxster (986), when starting off from cold, as soon as I dab the brake pedal the yellow PSM and ABS lights stay on. They go off only if the engine is stopped and re-started but only if the car has reached normal operating temperature.

Has anyone else encountered this and do you have any advice ?

[Don]

Had this.

Porsche replaced chunks of the loom under warranty apparently... Its a job for an OPC/Top indie specialist.

[damianc4s]

First check the wiring going to the MAF (even the MAF itself), if you try and start the car without having the MAF connected it will display the exact same warning lights.

[welshnobby]

....i had similar symptoms on my previous 996 c2 and a change of the MAF under opc extended warranty fixed the problem

[S99]

Apolgies for my ignorance but what is a MAF ?

[dava]

Mass Air Flow sensor. It'll cost you £300 from an OPC or lots less from eurocarparts and you can replace it yourself. Search RennTech.org for instructions.

If the MAF is bad the ABS/PSM won't work.

I had similar problems in my 986S. Intermittent ABS warning for no reason, then it came permanently on and switched off the PSM (which obviously can't work without using the ABS for it's selective wheel braking manoeuvres). Turned out to be a bad ABS sensor (fused!) on one of the wheels. Can't remember how much it cost to fix but probably around £100 quid and an hour at your local specialist.

[sportsandclassic]

could possibly be a faulty brake light switch too ...needs going on a diagnostic tester and see what is in there..

[butcherboy]

Same symptoms as my 996 - sounds like you need a new MAF Filter.