Antilock Brakes / Traction Control Systems: Description and Operation

Introduction

Application:
PSM 5.7 (Porsche Stability Management)
911 Turbo (996) model year 2001 (Z)


General Instructions/Safety Instructions


The following points must be observed during vehicle diagnosis:
- If the control module is damaged, the complete hydraulic unit with integrated control module must be replaced. When replacing a PSM control module, observe the coding of the control module (vehicle type, transmission type and chassis number) and calibration of the steering-angle sensor.
- The steering-angle sensor must be calibrated for all work on the running gear.
- After troubleshooting or repairs, erase the fault memory with the Porsche System Tester 2 and carry out a test drive.
- After the test drive, read out the fault memory with Porsche System Tester 2 again.


CAUTION:
Danger of damage.
- Never disconnect battery with engine running.
- Never start engine without securely connected battery.
- Never use boost chargers to start the engine.
- Disconnect the negative terminal of the battery before welding work on the vehicle.
- Never pull off or push on the wiring harness plugs of the control modules or other electronic components when the ignition is switched on.


General Information on the Fault Memory


The fault memory of the control module can save up to three different faults simultaneously. If all three fault memories are occupied, the new fault overwrites the oldest fault. It is possible to reset faults in the control module only after an "ignition off - on" procedure. The fault memory content of the PSM control module is maintained even in removed state.

Fault memory key [F8]

In order to be able to assess the fault exactly, the fault memory key [F8] must be pressed. This information should be saved using the [F4] key and printed out. If a fault code is stored with "not present" status and no other problems are present, then the fault memory must be erased.

- - - - -/Signal implausible/no signal change/open circuit or short to ground/short circuit to voltage

- - - - -: No details available.
Signal implausible: The incoming signal to the control module deviates from the signal expected.
No signal change: The incoming signal to the control module does not change.
Open circuit or short to ground: There is (present) or was (not present) a short circuit to ground or an open circuit in the circuit to the control module terminal.
Open circuit or short circuit to voltage: There is (present) or was (not present) a short circuit to voltage or an open circuit in the circuit to the control module terminal.
Short to ground: There is (present) or was (not present) a short circuit to ground in the circuit to the control module terminal.
Short circuit to B+: There is (present) or was (not present) a short circuit to voltage in the circuit to the control module terminal.

Light on
PSM light switched on.

present/not present
The fault is detected as present or not present.