24 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHPSM and ABS failure
Leading reported evidence
Replace alternator
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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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
After reading similar posts here, I had read about voltage issues, started with battery which was old, also replaced alternator which was not charging� I�ve been using a trickle charger for 2 years, all connections, brakes etc inspected, with no issues.
Leading evidence: 'Replace alternator' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'alignment' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Check battery cable connections' (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.
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Discussions that performed work without a confirmed outcome
1
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Performed · outcome unconfirmed
Battery was replaced about a year ago and everything is clean clean clean.
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
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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 suspect a cause
1
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Suspected cause
if the lights come on only when the car starts moving it is probably a bad alignment.
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
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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
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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
After reading similar posts here, I had read about voltage issues, started with battery which was old, also replaced alternator which was not charging� I�ve been using a trickle charger for 2 years, all connections, brakes etc inspected, with no issues.
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.
24 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Generation: 20261026T174436Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
A question regarding a Porsche 911 4S where the warning lights for ABS and PSM light up when the car is started.
As I said, both lights come on immediately when the car is started, but if you turn the car off and restart it,
they don't come on again and everything is fine.
What could this be due to?
Have looked around a bit on the internet and this is apparently a fairly common problem
with some relatively simple explanations but also some that seem less funny.
Any thoughts what could be the problem?
It seems strange that the lights don't come back on when the car is restarted immediately afterwards???
I don't have psm in my 2002, so can't comment if it's a common occurrence. But you may want to consider getting the Durametric software on your laptop or something similar. It will allow you the opportunity to run diagnostics when you want to see what's going on. Also allows you to reset codes.
happened to me after replacing front driveshafts/suspension components. my understanding was:
if the lights come on only when the car starts moving it is probably a bad alignment. did you do anything recently to affect the alignment? Hit a curb?
if the lights come on before the car starts moving it could be a wheel speed sensor, the steering angle sensor, or the mass air flow sensor
I had the car at a local Porsche Dealership before buying it to check the engine for eventual bore score.
During the time in the workshop I noticed that the mechanic took out the airbox to do the inspection.
Is it possible that something happened during the check or he didn�t get it right after he was done?
According to the seller, the issue with the warnings light havn�t happened before.
Just for clarity please correct this sequence how you see fit if it is incorrect;
- - -
Car is cold, not in motion:
Car start: PSM, ABS lights illuminated
Shut off car
Car start: PSM, ABS lights off
Car is in motion
: lights remain off?
Car parked till cold.
Car start: PSM, ABS lights illuminated
- - -
If this is the case, I agree that maybe the MAF is not plugged in all the way or got dirty while it was hanging loose. Give it a quick clean and plug it back in. If the lights illuminate while the vehicle is in motion you may need to start looking at alignment / wheel speed sensor issues.
Why not post a short video that shows the sequence of inserting the key, turning it to position 1 (accesories/Radio on), then pos 2 (ign on) then start. Speak each position out loud while recording and then drive till the state of warning lights no longer changes and post it here. You'll get answers quickly.
I took the car out this afternoon for a test.
* Car cold, and not in motion, turned the ignition and all the lights on the dashboard illuminates.
* Wait a couple of seconds for the oil check and then start the car.
* No illuminated ABS- or PSM-lights.
* Stand still for a minute or so without any issues.
* Put the car in reverse and immediately when the car moves, the ABS- and PSM-lights comes on.
Still a possible MAF problen or something else?
What Joe said^^^
Next check your wheel speed sensors. If they have not been replaced I'd bet they are cracked and you could have a slight interruption in signal.
If the lights do not illuminate until the vehicle is in motion then I would be looking at the wheel speed sensors first. I had one not plugged in after some work was done (I was the one who forgot to plug it in,) and these were exactly my symptoms.
Wheel speed sensors!
UNplug all but one of them. Drive car. If the lights come on, then that connected sensor
works.
If the lights stay off, then that sensor is bad because it gives no signal and the PSM interpretes this as the car being stationary.
Do this for all 4 wheel speed sensors, always making sure that only one single sensor is connected.
Of course, much easier would be using a durametric
Going out on a limb here but perhaps there's some sort of a timer that suppresses the bulb check (that's what it is and why all yellow and red warning lights/symbols light up on switching the ignition on) when switching ign off and on again directly after.
BTW you should have the person performing the check read my post and have him(her?) describe it in their own words. If what they repeat makes sense in the same way as my description does, he understands what to do. If not don't bother having this person perform the test as the result will probably not be reliable.
Sounds harsh but that just the way it is.
Have had similar problems. First time sensors lit up, was after exiting a gas station uneven surface. Went away after restart, then came back on a few weeks later. After reading similar posts here, I had read about voltage issues, started with battery which was old, also replaced alternator which was not charging� I�ve been using a trickle charger for 2 years, all connections, brakes etc inspected, with no issues. Most recently, after washing car and using high pressure car wash nozzle, light has come back on� I�m hoping that is the latest cause. We�ll see� thanks to all who contribute, next will check relay, speed sensors one by one 🤬??
Had this problem when I was replacing a wheel bearing. Didn't have the plug on the ABS "wheel speed" sensor seated correctly. Got the ABS light. Unplugged it, clean it with CRC electronic cleaner, plugged it back, and haven't had the ABS light since.
Not much to these sensors and so I can see how they'd crack or malfunction due to being exposed to the elements.
The ABS and PSM lights came on in my car today, immediately after installing a new 3rd brake light. I was on the way to the trails so we did our ride by the time I got home I had to cook dinner and frankly I'm beat. Tomorrow I'll swap the old 3rd brake light back in and see what's up, will update.
Update. I pulled out the Amazon 3rd brake light and it the original back in, and the error went away.
but, now I have noticed that I have a stuck caliper or something, can smell burnt brakes. See my other new thread. Maybe the two are related, maybe not.
Check your battery cable connections. Clean and re-tighten. They can play games with the ABS and PSM lights if the connections isn't a good as it should be.
Bringing this up to the top. I have a weird issue. I get this when:
Car is cold, not in motion:
Car start: PSM, ABS lights illuminated
Shut off car
Car start: PSM, ABS lights off
BUT only after washing the car and only after starting the car right after the wash. I was thinking there might be a short but the car is still wet after I turn it back on and I don�t get any lights anymore. Can�t figure this out.
I replaced the MAF since I had a new spare and this didn�t do anything (I want to go MAFless tune sometime next year). Battery was replaced about a year ago and everything is clean clean clean.
Start by getting a Durametric or PIWIS to see what the "self-test" has to say about the issue instead of guessing or heading off in the wrong direction...
The test equipment will pay for its self, unless you plan to get someone else to fix it after you " figure it out"...
I�m the type of guy that likes to do my own work but yeah, I agree with you. Time to purchase that, like you said, worth the money. This TT is my project car. Got it for cheap because it needed some TLC. I�m just dealing with mostly cosmetic stuff now and this is the only technical/issue I can�t figure out.
I also just realized this is in the non-turbo section but I would assume the system is the same in a TT and C4.
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