Introduction

General Instructions/Safety Instructions
The following points must be observed during vehicle diagnosis:
- In the case of a defective control unit, the entire hydraulic unit must be replaced.
- When replacing the hydraulic unit, pay close attention to its coding.
- After troubleshooting or repairs, erase the fault memory with the Porsche System Tester II No. 9588 and carry out a test drive.
- After the test drive, read out the fault memory with the Porsche System Tester II No. 9588 again.

CAUTION:
Danger of damage due to improper handling of batteries and control module plug connections.
- Disconnect the battery connection terminals only when the engine is switched off.
- Start the engine only when the battery connection terminals are properly connected.
- Pull off or push on plug connections for the control units or other electronic components only when the ignition is switched off.
- Disconnect the negative terminal of the battery before welding work on the vehicle.

New Speed Sensor
New active speed sensors have been introduced in the ABS 5.7. They are equipped with semiconductor elements and work according to the Hall principle. The connector plugs are designed in a way which prevents any confusion.

CAUTION:
- Risk of destruction of the speed sensors during resistance measurement.
- Risk of destruction of the speed sensors if the connector pins are interchanged.
- Do not carry out a resistance measurement on the speed sensor.
- When connecting, make sure that the polarity is correct.

Communication Between Control Module And Porsche System Tester II No. 9588
The following conditions must be met in order to establish communication between the vehicle electrical system control module and the Porsche System Tester II No. 9588:
- Porsche System Tester II No. 9588 connected to data link connector
- Ignition on
- Battery positive voltage > 11 V
- Voltage supply for the ABS control unit is in order

General Information On The Fault Memory
- The fault memory of the control unit can save up to three different faults simultaneously
- If all three fault memories are occupied, the new fault overwrites the oldest fault
- The contents of the fault memory are retained even when the unit is removed
- It is possible to reset faults in the control unit only after an "ignition reset (off - on)" procedure

Diagnostic Conditions
The fault can only be identified if the requirements listed under 'Diagnostic conditions' are met. For this reason, the specified procedure must be observed after a fault is repaired:
1. Erase fault memory
2. Satisfy the requirements listed under 'Diagnostic conditions'
3. Read out fault memory again

Possible Causes Of Fault
The possible fault causes that may be responsible for the fault are listed here. Please note that in certain circumstances further faults can be stored in the fault memory after troubleshooting (e.g. if plugs are disconnected). After carrying out repairs, read out the fault memory of all control modules and erase any faults.

Diagnosis/Troubleshooting
The fault memory Info key F8 on the Porsche System Tester II No. 9588 can be used to access the extended fault memory. This information should be saved using the F4 key and printed out.

The following information can be displayed:

- Fault type
The following fault types are possible:
- -- (No details available)
- Short circuit to B+
- Short circuit to ground
- Signal implausible
- No signal change
- Open circuit/short circuit to B+
- Open circuit/short circuit to ground
- Open circuit
- Below limit value
- Above limit value

- Fault status
The following status types are possible:
- Present - at the time of the previous control-unit routine (Refer diagnostic conditions)
- Not present - at the time of the previous control-unit routine (Refer diagnostic conditions)