16 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHPSM and ABS indicators popped on for no good reason
Reported or suspected cause
flaky/faulty brake light bulb
Reported cause
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
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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 remember reading about some other ABS/PSM problem, and it turned out to be a flaky/faulty brake light bulb.
PSM and ABS indicators popped on for no good reason
Read full discussion summary
Leading evidence: 'flaky/faulty brake light bulb' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'flaky/faulty brake light bulb' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check brake switch asap' (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 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.
PSM and ABS indicators popped on for no good reason
Replace maf and all good
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
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 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.
PSM and ABS indicators popped on for no good reason
Replace maf sensor (fixed it
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
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 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.
Performed · outcome unconfirmed · Original poster
After replacing MAF sensor (fixed it for 3 months), then the brake vacuum sensor thingy ($120 down the drain - zero effect), I Finally did the $20 brake switch replacement.
PSM and ABS indicators popped on for no good reason
Outcome qualification: Negation, uncertainty or missing explicit repair resolution overrides the raw extraction signal.
Use code reader and got enough code data
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
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 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.
Performed · outcome unconfirmed
I used a code reader and got enough code data to confirm a bad MAF.
PSM and ABS indicators popped on for no good reason
Replace maf sensor (fixed it
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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.
Performed · outcome unconfirmed · Original poster
After replacing MAF sensor (fixed it for 3 months), then the brake vacuum sensor thingy ($120 down the drain - zero effect), I Finally did the $20 brake switch replacement.
PSM and ABS indicators popped on for no good reason
Coverage and how to read this overview
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.
16 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 1 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T103553Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Two nights ago on the way home from the office, in a light drizzle and 64 degree temps, as I rounded a corner my ABS and PSM indicators lit up. Used PSM button to attempt to override (on/off) - no reaction. Drove home, no big deal. Turned off the car. Counted to 5, restarted. No lights, and now when I press PSM button it goes off, then back on when I press the button exactly as it is supposed to do.
I then took a "spirited" drive involving trail braking around the neighborhood during and after which the indicators stayed off.
Alternator looks like it is charging, battery is showing 12.7 volts and brake fluid is 100% full.
I am suspected this is not a big deal and "just happened" I'm driving the GT3 to the office and will take the 996 out for a longer loop on Saturday.
Any thoughts on this?
I remember reading about some other ABS/PSM problem, and it turned out to be a flaky/faulty brake light bulb. So might want to put that on the list of things to check as well.
As hokey as this sounds, I had a bad MAF which triggered the PSM system to go off, especially when I put the car through a quick throttle action. I used a code reader and got enough code data to confirm a bad MAF.
Replaced the MAF and all good.
I had the same issue, including the fault going away for a period of time. Mine turned out to be the steering angle sensor.
Durametric found the fault right away, might be worth having it checked. Best of luck, I hope it is nothing, or at most the brake pedal sensor.
I've had this happen for both the steering wheel angle sensor being triggered when I bought the car with a bad alignment, and a wheel speed sensor that was not fully plugged back in after a service. When I was researching this issue for myself I found that the PSM/ABS warning light combo indicates a whole laundry list of faults. I'm hoping yours is something easy like mine.
FWIW - If it's your brake switch, (a common cause,) you will notice a direct correlation between your foot on the brake and the lights on the dash. If it's intermittent this could be annoying to pay attention to. My wheel speed sensor fault illuminated with ignition of the car, it was instant and constant. My steering wheel angle sensor fault took 5 minutes, but then was constant and didn't clear until I turned the car off.
Good luck!
More great suggestions - thanks! I plugged in the code reader too, just because, but no codes showed. I'll check MAF and bulbs and do some research on the steering wheel angle.
Rennlist is an amazing community.
This happened to me on the drive home from buying the car. It was early morning and slightly rainy - the car had sat in the hotel parking lot overnight - and I decided to open it up a little. The lights came on around 119mph so I backed off, pulled over, restarted the car, and they've never come back on. I'm thinking it was some kind of misread due to moisture on the sensors.
I second the brake switch failure... happened to me in my C4S when I would quickly tap the brakes at slow speeds.It's a 10 min job to replace
Brake Light Switch at Pedal
Part #: 996-613-113-02-M100
This story has a Happy Ending
After replacing MAF sensor (fixed it for 3 months), then the brake vacuum sensor thingy ($120 down the drain - zero effect), I Finally did the $20 brake switch replacement.
The original brake switch was definitely not quite right, as the spring seemed to have compressed a bit and stayed that way.
ABS & PSM lights are off.
Glad you found the cause. It's not easy with these cars. I had the ABS/PSM lights when I forgot to reconnect my MAF after removing and replacing my airbox.
Thanks for the update! Such behavior should mandatory as it will help others in the future. Also furthers the knowledge base... guess what I'm checking first should this ever happen to me?
No, not the imsb.
This is a source reference. Confirm exact model applicability in the original material.
