PSM Fault

[mneil]

18 minutes ago, Dermot said:

my fault was fixed by new pedal bushes.  I was charged 1hr labour for the job.

Result 😃 and only I hour labour, presume it's a PDK.

Had the new bushes under warranty, mines a manual so considerably more work. I do spray them with PTFE as a precaution but 🤞 it's a fix now with new speed sensors all round. 

[gibbo]

Hello all. I too have had the trio of warnings, PSM/ABS Parking brake,  drive on poss ect. After a lot of searching and fault code reading i changed a rear ABS sensor myself. The problem came back almost immediately. so as im now looking around under my brake pedal and looking for the brake pedal switch, i notice that there is NOT one there!!

 

How is that possible? i owned the car 2 and a half years, and it was alright until 5 months ago??

I have checked and there is no brake pedal switch, and i can't see where the cable would come from to attach to it??

I will post pictures if i get any reply. 

[alank]

As mentioned above, i think you will find it is the Brake Pedal Bush, mine did exactly as yours has. Had it done at an Indie under warranty as it happened on way home from picking up car ( good start to 981 ownership)

[Stuart21UK]

If brake pedal bush like mine, then the brake lights will be permanently on when driving possibly (mine were)

Edited April 13, 2022 by Stuart21UK

[gibbo]

would that be on the master cylinder or servo?

i don't have a switch/bush under the pedal?

[iborguk]

27 minutes ago, gibbo said:

would that be on the master cylinder or servo?

i don't have a switch/bush under the pedal?

https://rennlist.com/forums/981-forum/1119048-981-brake-light-switch-diy.html

 

[iborguk]

48 minutes ago, gibbo said:

would that be on the master cylinder or servo?

i don't have a switch/bush under the pedal?

Re one of your other threads posts the errors returned from your scan.

I'd suggest check if they are active faults and start by checking your battery.

 

000021

Diagnosis information ­ Parking brake control unit DAR (DriveAwayRelease) not available

Diagnostic conditions

The control unit must be active in order to test internal function sequences and diagnosable inputs/outputs.
In the event of a fault, check whether the fault is permanently >present<. To perform the check, erase the fault memory, meet the diagnostic conditions and read out the fault memory again.

Ignition on

Fault setting condition(s)

Doors not closed
Driver seat belt not fastened

 

Fault effects

The parking brake does not release automatically when the intention to drive off is detected

 

 

004223

Diagnosis information ­ PSM control module Speed sensor ­ Mechanical fault

INFORMATION
If electrical faults are stored for the rpm sensors, please remedy the electrical faults first before continuing with remedying the following faults.

Diagnostic conditions

The control unit must be active in order to test internal function sequences and diagnosable inputs/outputs.
In the event of a fault, check whether the fault is permanently >present<. To perform the check, erase the fault memory, meet the diagnostic conditions and read out the fault memory again.

while driving

Fault setting condition(s)

Speed sensor installed incorrectly

Speed sensor Faulty
Wheel bearing installed incorrectly
Wheel bearing ( Multi­pole ring ) Faulty I Wheel carrier damaged

PSM control module Function restriction IS

Fault effects

none or Limited function PSM

Edited April 15, 2022 by iborguk

[gibbo]

Thanks for your reply.

im a still a bit confused to be honest.

that  link https://rennlist.com/forums/981-forum/1119048-981-brake-light-switch-diy.html

shows a different set up with the switch on the brake pedal.

The read out said they were both current faults 

I did check the battery when i got home from work and got 12.4. V

I checked again just now and only got 12.02 (2 days later having not driven it), so you could be right about the battery. I changed the ABS sensor, and  cleared the fault codes,.

just need to check if they've come back and are still current after they have been cleared. 

I can do that till tuesday when i an borrow the icarsoft tool. 

 

[iborguk]

1 hour ago, gibbo said:

Thanks for your reply.

im a still a bit confused to be honest.

that  link https://rennlist.com/forums/981-forum/1119048-981-brake-light-switch-diy.html

shows a different set up with the switch on the brake pedal.

The read out said they were both current faults 

I did check the battery when i got home from work and got 12.4. V

I checked again just now and only got 12.02 (2 days later having not driven it), so you could be right about the battery. I changed the ABS sensor, and  cleared the fault codes,.

just need to check if they've come back and are still current after they have been cleared. 

I can do that till tuesday when i an borrow the icarsoft tool. 

 

I don't have a 981 so can't check re the switch for you. @daz05 any insights ?

Did you check whether your brake lights are on as per @Stuart21UK's post ?

Is your car manual or PDK ? 

The brake pedal switch/sensor is part number 97060645100 and I've yet to find a diagram showing that , it's just referred to.

The brake pedal bushes , which others refer to as a source of issue in this thread are part 6 on the diagram below, seems to be the same part for manual or PDK but check my thinking there...

https://www.lllparts.co.uk/en/product/porsche-7pp721113a-bush/mpn/7pp721113a

Edited April 16, 2022 by iborguk

[gibbo]

thanks for your reply. 

brake lights are working 

car is PDK

I don't think my car has that switch  97060645100 unless im mistaken )  Just a hole where it should be. I believe its in the master cylinder in my model, but can not find exactly where. 

I don't think its the bushes, as my pedal doesn't seem to stick. 

 

[Richard Hamilton]

This is from the workshop manual: <Remove and replace brake light switch>

That's the only reference I can find.  What model and year is your car?

[gibbo]

I don't think have that switch. as its not there. 

I believe later models have it located in the master cylinder?

I have a 2014 cayman 

[Richard Hamilton]

Very odd.  The parts catalogue shows the same switch part number for the Cayman.  Unfortunately, the 981 manual I have is an early one, and doesn't have supplements.  I can't see anything in the technical bulletins I have.

Having said that, I looked at the 718 parts lists, an it doesn't show a switch on the diagram for the pedal.  Trouble is, I can't find anything on the master cylinder or servo either.  Bit of a mystery.  I'll keep looking, but don't wait for me......

From what's been said, and the fault codes above, I think it is unlikely to be the brake light switch anyway.  I think you need to do some more checks.

[gibbo]

i just check my battery voltage after being parked 2.5 days and it was 11.8, so its dropping over the first few days. 

I just ordered a battery. 

ill let you know how it goes. 

cheers