996 turbo warning lights

[james964]

Hi

PASM and ABS warning light have come on on start up. Seems to drive ok. Had a similar issue before which turned out to be a loose vacuum pipe but the car ran poorly and you could hear the turbos whistling so dont think this is the same issue.
Maybe the MAF sensor?
Is there a way to confirm this before buying a new 1?
Any help would be appreciated.

[Steviesam]

Maf is often, but not always the casue of these warnings.

You could take it out and clean it, with non residue electrical cleaner.

[LeighB]

Hi James,

There's a few threads on this issue and could be one of several things causing it.

I've recently had this myself and turned out to be a broken wire in the part of the loom that runs from the offside front ABS sensor to the ABS module. They are prone to wear where the loom goes through the bulkhead and/or sits against the steering column and visually you would not think anything was wrong. Diasgnostics will normally keep teeling you that the ABS sensor is at fault.

It's not an easy job to do and if yours turns out to be the same, you can buy 'partial' repair looms from Design 911.

The only reason this was looked at in any detail was from reading the threads on here so a big thanks to those who suggested it.

I have compiled a list of the known potential culprits from the threads I've read:

Brake pedal switch

Boost leak

MAF sensor

Air leak after MAF

Battery failing

ABS pump

Wheel speed sensor

Ignition switch

O2 sensor

Steering angle sensor

Alternator

ABS module

Common weak point in the wiring from the brake pad wear / wheel speed sensors. The ABS wiring loom apparently goes across the steering column somewhere and eventually it wears thin.

“The wire to the front offside wheel sensor had an intermittent fault which threw the PSM/ABS lights.” & “Apparently the wires break down inside the insulation at the point where it goes through the bulkhead. There is no visible sign and isn't detected in a continuity check unless the circuit is broke at the time of testing.”

Previous threads for reference:
thread 1
thread 2
thread 3

[james964]

I have just had a flat battery so maybe worth changing this before looking in to much else?

[AlexA911]

Deffo charge the battery first.

[monthefish]

james964 said:

Hi
Maybe the MAF sensor?
Is there a way to confirm this before buying a new 1?

Am I right in thinking you can take the MAF out and run the car without it (briefly) and if it's the MAF sensor at fault, the car will run fine?

Anyone clarify?

[davek_964]

monthefish said:

james964 said:

Hi
Maybe the MAF sensor?
Is there a way to confirm this before buying a new 1?

Am I right in thinking you can take the MAF out and run the car without it (briefly) and if it's the MAF sensor at fault, the car will run fine?

Anyone clarify?

You can disconnect it and it will run on default values. But in this case it wouldn't help much since it would still throw the same warning lights.

[james964]

Battery charged but lights still on! Is there an easy way of confirming MAF sensor fault?

[james964]

Battery charged but lights still on! Is there an easy way of confirming MAF sensor fault?

[markcoznottz]

james964 said:

Battery charged but lights still on! Is there an easy way of confirming MAF sensor fault?

Just buy a new one, they go wrong a lot. Peace of mind.

[Magic919]

Can you not unplug the MAF on these as a test?

[davek_964]

When mine failed, I was able to confirm it by checking the MAF values with Durametric. But without that (or some kind of diagnostics) you won't be able to check without testing a new one and seeing if the lights go out.

[pmr01]

I had similar problems with my car. I tried to diagnose it in my head and worried about it for age. Found a trusted Indy and got it diagnosed for £30. It was a faulty abs sensor which was far from dear and the car was great after that.Might not be the same but worth a bash.

Edited by pmr01 on Thursday 25th April 00:41

[monthefish]

Magic919 said:

Can you not unplug the MAF on these as a test?

That's what I thought, but see above/below

davek_964 said:

monthefish said:

james964 said:

Hi
Maybe the MAF sensor?
Is there a way to confirm this before buying a new 1?

Am I right in thinking you can take the MAF out and run the car without it (briefly) and if it's the MAF sensor at fault, the car will run fine?

Anyone clarify?

You can disconnect it and it will run on default values. But in this case it wouldn't help much since it would still throw the same warning lights.