ABS/PSM lights on + weird brake light problem

[martinkm]

Hi

I have a 2002 Targa 996 manual transmission with 47K miles. A month or so ago I washed the car and then had to leave it for a long weekend. The first time I drove the car I had ABS/PSM lights on after driving. I turned off the car, restarted and didn't see the codes again until the next day. The next day it happened again, but restarting only cleared the codes temporarily.

After awhile I discovered that the codes would appear after releasing the brake pedal after it had been held for at least 2 seconds.

After reviewing these forums I checked my brakes and realized that my brake lights were only flashing briefly when I hit the brakes.

I swapped out the brake activation switch tonight and the problem remains! What is most strange is that the break light comes on if I press the break pedal lightly - i.e. the pedal just comes off the switch. If I press more firmly, the break light goes out again! This makes me think there must be another switch somewhere in the break circuit?

I tried to read out the codes with an unit I rented at Autozone but it said everything was OK so I think I need a more sophisticated unit. I know I need the codes to really get good feedback but was hoping someone could shed some light on this weird brake light issue.

thanks,

Ken

[Loren]

If you have a US car then their are two switches on the brake pedal - one for the brake lights and one for the cruise control. Are you sure you got the right one?

Should be easy enough to test with a jumper wire.

[martinkm]

If you have a US car then their are two switches on the brake pedal - one for the brake lights and one for the cruise control. Are you sure you got the right one?

Should be easy enough to test with a jumper wire.

Hi Loren - thanks for all the help you provide here.

It is a US car, and I saw two switches on the pedal. The one I replaced is normally pressed by the break pedal and is released when the pedal is pressed. the second switch to the side doesn't appear to be pressed until the brake pedal is depressed a very long way. I asked the parts guy for the "brake switch activation switch" - the bag has part number 996 613 113 01 and has 4 leads.

what would I short to test with a jumper wire?

thanks again!

Ken

[martinkm]

If you have a US car then their are two switches on the brake pedal - one for the brake lights and one for the cruise control. Are you sure you got the right one?

Should be easy enough to test with a jumper wire.

Hi Loren - thanks for all the help you provide here.

It is a US car, and I saw two switches on the pedal. The one I replaced is normally pressed by the break pedal and is released when the pedal is pressed. the second switch to the side doesn't appear to be pressed until the brake pedal is depressed a very long way. I asked the parts guy for the "brake switch activation switch" - the bag has part number 996 613 113 01 and has 4 leads.

what would I short to test with a jumper wire?

thanks again!

Ken

ahh- I think I might have gotten turned around and swapped the switch and the clutch...

sorry to waste your time.

thanks again,

Ken

[luvmyc4s]

Hi

I have a 2002 Targa 996 manual transmission with 47K miles. A month or so ago I washed the car and then had to leave it for a long weekend. The first time I drove the car I had ABS/PSM lights on after driving. I turned off the car, restarted and didn't see the codes again until the next day. The next day it happened again, but restarting only cleared the codes temporarily.

After awhile I discovered that the codes would appear after releasing the brake pedal after it had been held for at least 2 seconds.

After reviewing these forums I checked my brakes and realized that my brake lights were only flashing briefly when I hit the brakes.

I swapped out the brake activation switch tonight and the problem remains! What is most strange is that the break light comes on if I press the break pedal lightly - i.e. the pedal just comes off the switch. If I press more firmly, the break light goes out again! This makes me think there must be another switch somewhere in the break circuit?

I tried to read out the codes with an unit I rented at Autozone but it said everything was OK so I think I need a more sophisticated unit. I know I need the codes to really get good feedback but was hoping someone could shed some light on this weird brake light issue.

thanks,

Ken

Hi Ken,

This is my first post, if I do it right.I recently bought a 2002 C4S which had developed the seemingly ubiquitous PSM/ABS warning light.I bought a Durametric analyzer and got a 4460 fault code for brake sensor.I cleared the code, it then reappeared again and went off by turning off the car.I then took to TRE motorsports in North Hollywood and Jeremy got the same 4460 code, cleared it, but referred me to a dealer because he didn't know what it was.I have another friend with a 99 C4 with the same problem and it seems that quite a few others in this forum have it also.The very first time this happened to me, my front lights went out about 1-2 seconds after the PSM/ABS warning lights came on. I think that I have an electrical problem. With so many having the same problem, I wonder if Porsche could be persuaded to start some type of recall? Cross my fingers, but since TRE cleared the code, I haven't had the problem, but I expect it to rear its ugly head at some point.

[Loren]

Fault code 4460 - Pressure sensor

Pressure sensor actual value is evaluated and displays an implausible value.

Possible cause of fault

. Short circuit to ground/B+ or open circuit

. Plug connection on stop light switch faulty

. Incorrect adjustment of the stop light switch

. Wiring/plug connection between pressure sensor and control module faulty

. Pressure sensor faulty

Note!

A malfunction of the stop light switch can cause this fault. The stop light switch must have switched before a brake pressure is recognized. When the brake pedal is actuated, the stop light switch and the brake lights are triggered. The brake pressure on the pressure sensor is 0 bar.