Control Unit Function

Control Unit Function

Replace Control Module

CAUTION: Risk of damage due to build-up of corrosion in plug connections.

This can cause malfunctions and system failures:
- When removing hydraulic unit pull off plug as the last step
- Protect plug connections from fluids
- Completely remove fluids that have ingressed using suitable agents
- When installing hydraulic unit push on plug as the last step

If the control unit is damaged, the complete hydraulic unit with integrated control unit must be replaced. Observe the following points:
- The control unit must be coded for the corresponding type of transmission (manual transmission/Tiptronic).
- The Vehicle Identification Number must be entered.
- A static test and the swap test must be performed using the Porsche System Tester II No. 9588.

Static Test

NOTE: This test must be carried out after the hydraulic unit has been exchanged.

This test involves carrying out the valve and pump motor test. The test is normally not started until the vehicle moves off (speed > 6 km/h). The valve and pump motor test includes actuating all ABS valves and the pump motor and checking their feedback. It only makes sense to carry out the "Static test" function if no fault has previously been detected as present, i.e. the system is not switched off.

PROCEDURE:
1. Using the Porsche System Tester II No. 9588 read out the fault memory and remedy the fault entered.
2. Select the menu item 'Static test'.
3. Switch off ignition.
4. Switch ignition on.
5. Wait until the display 'Fault memory' appears and remedy any faults entered.
6. After remedying faults, repeat the test from step 2.

Swap Test

NOTE: This test must be carried out after the hydraulic unit has been exchanged.

The swap test is used to check the allocation of the brake pressure lines to the wheel brake cylinders. A hydraulic and an electrical test are carried out.

PROCEDURE:

NOTE: On confirming a prompt with No the Porsche System Tester II No. 9588 will cancel the test.

1. Select the menu item 'Swap test' using the Porsche System Tester II No. 9588.
2. Use the Up Arrow and Down Arrow keys to select a range (e.g. 'Hydraulics front left').
3. Press the F8 'Start' key.
4. Press the >> key, then actuate and hold the brake depressed throughout the test.
5. Press the >> key. Then check if the front left wheel is rotatable but all others lock up. Confirm with the appropriate key Yes/No and the >> key.
6. Check if all wheels lock up. Confirm with the appropriate key Yes/No and the >> key.
7. Now check if the front left wheel is rotatable but all others lock up. Confirm with the appropriate key Yes/No.
8. Check if all wheels lock up. Confirm with the appropriate key Yes/No and the >> key.
9. Release brake and continue with step 2 in another range.