ABS/PSM

[leeshdw]

I am getting the ABS/PSM warning lights. It goes on as soon as I turn on the parking lights.

One thing I noticed. All 3 brake works normal when the parking lights are off. As soon as i turn on the parking lights the ABS/PSM warning lights come on. The 3 brake lights comes on without pressing the brake pedal.

I checked with my Durametric software and got the following faulty code.

4340 stop light switch

P0571 Porsche fault code 364-Brake pedal position sensor

I already changed my stop light switch. But still getting the fault code.

Does anyone know where the brake pedal position sensor is and how hard is it to change out?

[Loren]

There are two switches on the brake pedal (one is for cruise control) - Are you sure you changed the right one?

[leeshdw]

I changed it with this one.

http://e-partssales.com/Merchant2/merchant...=986BRAKESWITCH

[RFM]

The brake switch # is 996 613 113 01 and should have a brown colored body top.

[Loren]

I changed it with this one.

http://e-partssales.com/Merchant2/merchant...=986BRAKESWITCH

Sorry, that is the wrong one.

You want the one RFM mentions above 996.613.113.01

[leeshdw]

I will verify the part number. The one i changed is right at the brake pedal.

[leeshdw]

that is the correct switch i got. Part number is correct. what is the Brake pedal position sensor in one of the fault code?

[Loren]

[leeshdw]

Loren,

That is the switch i changed out. I noticed another thing this morning. With my parking lights off. When I press my brake pedal, I see the passenger side marker and the light in the headlight light up. I only noticed the passenger side and not the driver side. What else could be wrong?

Thanks.

[Loren]

Loren,

That is the switch i changed out. I noticed another thing this morning. With my parking lights off. When I press my brake pedal, I see the passenger side marker and the light in the headlight light up. I only noticed the passenger side and not the driver side. What else could be wrong?

Thanks.

Sounds like you have a short somewhere.

Any recent wiring work done (aftermarket radio, etc.)?

[leeshdw]

No electrical/wiring done on the car. Guess it is time to bring it into the dealers.

[leeshdw]

No electrical/wiring done on the car. Guess it is time to bring it into the dealers.

Didn't have time to bring to the dealer yet. I noticed I can't turn on cruise control. I accidently hit the cruise control on/off switch and noticed the light didn't turn on. Is there a similar switch for the cruise control?

[wvicary]

I think you have a poor/false ground. Any moisture in the light assemblies? Might be best to take it in the the dealer or a good indie.

[RODAN]

Did you ever solve this?

 

These threads are almost useless without the person asking posting what finally solved their problems.

 

I have the same problem. Am I looking at a MAF, a wiring harness, one of two switches, a weak ground? 

 

Can someone please actually post what they've done to solve these problems? This was 2008. I have to believe that Leeshdw solved the issue somewhere between 2008 and 2015.

 

I'd certainly be grateful.

 

Cheers.

[RODAN]

Just to close the loop for everyone. I found on another site where someone had recently installed LED brake lights and had these symptoms.

 

I had just replaced the 3rd lights with LEDs this week. They light up properly. In addition, I had replaced the conventional taillights with LEDs as well in the week prior.

 

My first step so far has been to take the 3rd lights out and replace them with the stock units. This seemed to clear the issue immediately. No Durametric required.

 

I have a strong suspicion that the system is placing a test signal on the lights during POST (Power On Self Test.) and the fact that either the LEDS are unidirectional is rectifying the signal and giving a really confusing response to the system. Or, the current that is produced when the voltage is imposed is causing an issue.

 

I hope that this helps others that have this problem. And I promise as a member I will post my solution whenever possible when everyone here attempts to help out.

 

Cheers!

Edited January 25, 2015 by RODAN

[RODAN]

To close out the fix for the ABS/PSM fault when installing all LED rear brake lighting: (2003, 996 C2)

 

Purchased a 50 Watt, 30 Ohm resistor. A lot of people are using extremely low value resistors (I see 6.8 Ohm in many cases. This will get hot.) . 30 Ohms seems to keep the ECU happy and during application of the brakes will only dissipate 6 Watts of power nominally. This leaves the highest ambient temperature for the resistor that I used to operate safely somewhere about but shy of 400 degrees F. Should be fine.

 

The resistor should be applied between the brown (GND) and black (Brake light) wires on the taillight assembly (Assuming you are reusing your lighting harness. More expensive tail light assemblies I believe have this integrated.). On the car side of the harness connector these are the brown (gnd) and black with orange (Brake light) wires.

 

I installed only a single resistor behind the driver's side tail light and it immediately resolved the issue.

 

This is the part I used.

 

http://www.digikey.com/product-detail/en/KAL50FB30R0/KAL50FB30R0-ND/1646204

 

I'm also going to perform the same mod to a 2001 996 C4. Since the body electronics are a bit different I'll post whether this is successful here as well.

 

Cheers.

[Jaguwire]

Just want to thank Rodan for this post.  The 30 ohm resistor solved the same problem with my 2003 X50.  Cured a major headache for me.