15 captured repliesPartial discussion capture · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHABS/PSM light up
Reported or suspected cause
caused by a faulty brake light switch
Reported cause
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that report identifying a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Reported cause
I know on Mercs a similar problem is caused by a faulty brake light switch that costs £10.
Leading evidence: 'caused by a faulty brake light switch' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'caused by a faulty brake light switch' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check ' light will probably flash as well' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
Do a search on here for more info, but its most likely the MAF sensor (air flow).
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
It is more likely electrical in the ABS / brake circuit - if MAF is really bad the 'engine check' light will probably flash as well.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
I was going to say that, but wouldn't it trigger the Engine check light too?
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Unsuccessful attempt
John, I had this and it was brake pedal switch in my case (althoug the MAF was also faulty and changed first, but didn't solve the original problem so dealer kept looking).
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
15 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
911uk: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T144035Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
5 days into my first Porsche and both warning lights appear last night on a run down the coast.
Both indicate failure and a return to workshop message!!
Whats going on?
Help
John
Migration info. Legacy thread was 130343
Er possibly ABS & PSM?
I know on Mercs a similar problem is caused by a faulty brake light switch that costs £10.
Migration info. Legacy thread was 130349
My old 996 Targa did this every now and again. If by switching off the engine and restarting clears the warning ligts I wouldn't worry too much. However if they do stay on get it seen to PDQ.
Migration info. Legacy thread was 130354
Get it checked just to be sure. No point having the lights if you not going to act on them. Probably nothing too serious if they are not staying on.
And keep your fingers crossed.
Migration info. Legacy thread was 130372
Had the same. Do a search on here for more info, but its most likely the MAF sensor (air flow). I drove for 3mths with them coming on occasionally (1 in every 5 drives) and then they were fixed under warranty at same time as service - some sensor in the slave cylinder. You might find they only come on sometimes, not every drive. See it as a challenge to drive the beast without ABS... should keep you on your toes! (or put the car in the bushes...)
Migration info. Legacy thread was 130395
It'll be a faulty MAF, you can reproduce this on any non-faulty car by not reconnecting the plug to the MAF sensor..... :wink:
Migration info. Legacy thread was 130463
Thanks for your advice.
What does the mass air flow sensor actually do?
I have been in touch with the service department and this is what I've been told to try and get a diagnosis before I take it back.
1.Switch off the PSM
2.Drive quite quickly on a quiet road 50-60mph and brake hard to get the ABS to work.
3.See if the ABS FAILURE LIGHT COMES ON.
I have done this without ending in the bushes and got the ABS to work.At that time the ABS light did not come on.However a few miles from home the ABS Failure light and PSM FAILURE LIGHT came on even though I had switched it off from the moment I started the test.
I will relay this info to the garage tomorrow and let you know how things develop.
Love the car...................glued to the road..................but its bloody tropical conditions in South Wales!!
Migration info. Legacy thread was 130490
John, I had this and it was brake pedal switch in my case (althoug the MAF was also faulty and changed first, but didn't solve the original problem so dealer kept looking).
It is more likely electrical in the ABS / brake circuit - if MAF is really bad the 'engine check' light will probably flash as well.
Migration info. Legacy thread was 130530
BTW MAF sensor measures the precise amount of intake air going into the engine to enable exactly the right amount of fuel to be injected at all times. This prevents unburnt fuel entering the exhaust system and knackering your cats - and polluting the environment.
It also stops flames coming out of your exhaust on the overrun - which is a damn shame! :roll:
Migration info. Legacy thread was 130534
Well I am back from the dealer and a faulty brake switch was to blame.They have carried out further tests and we are 200 miles post repair and no flashing lights.Will keep a close eye on things and let you know.Will post a pic when I get round to it!!
John
Migration info. Legacy thread was 135147
