2000 996 ABS SRS Lights

[355Aloha]

HELP

Porsche repair shop put in three switches and 7 weeksof working on car, problem not resolver Codes PSM 4340 Brake posistion Sensor & DME P1574 Stop Light Switch fault come up.

The system is cleaer on start up but alarms come up 1-10 min after driving.

HELP

[Loren]

Fault code 4340 Stop light switch

Possible cause of fault:

- Short circuit to ground/B+ or open circuit

- Wiring/plug connection faulty

- Mechanism of the stop light switch not OK

- Adjustment of the stop light switch not OK

- Pressure sensor plausibility

P1574 Stop Light Switch – Signal Implausible

Fault area:

Both stop light switches closed.

– Stop light switch

– Wiring harness

If they have replaced the switches then the problem is likely the wiring.

There are simple tests to determine the problem in the manuals. You will also need a special tool used to measure continuity to the DME and a volt/ohm meter.

[355Aloha]

Fault code 4340 Stop light switch

Possible cause of fault:

- Short circuit to ground/B+ or open circuit

- Wiring/plug connection faulty

- Mechanism of the stop light switch not OK

- Adjustment of the stop light switch not OK

- Pressure sensor plausibility

P1574 Stop Light Switch – Signal Implausible

Fault area:

Both stop light switches closed.

– Stop light switch

– Wiring harness

If they have replaced the switches then the problem is likely the wiring.

There are simple tests to determine the problem in the manuals. You will also need a special tool used to measure continuity to the DME and a volt/ohm meter.

[355Aloha]

Thanks Loren

I tried a experiment:

I removed the switch out of the socket and drove the car, The PSM Off and ABS lights came on.

I removed the wire from the switch out of the socket and drove the car, The PSM Off and ABS lights came on again.

The auto shop said they traced and checked all the wire back to the controllers, and the wires checked out OK.

Any other ideas besides a stick of TNT?????

Thanks

John

[355Aloha]

Loren

After 4 Months WE Found The Problem

WE checked the following:

Voltage while driving, OK

New battery

All new tail lights

3 new brake switches

Tested all the wire form the test sheets you sent me OK

The fix was:

At the CPU behind the seat we shielded th wires. Problem fixed

All fault codes are clear and fault ligt stay off

Loren, Any ideas why this problem came up to begin with.

[Loren]

Very strange indeed.