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Home >> Porsche >> 2000 >> Boxster (986) F6-2.7L >> Repair and Diagnosis >> Brakes and Traction Control >> Antilock Brakes / Traction Control Systems >> Testing and Inspection >> Component Tests and General Diagnostics >> PSM 5.7 >> Control Unit Function

Control Unit Function



Control Unit Function

Replacing Control Unit

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

This can cause malfunctions and system failures:
- When removing the 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 the hydraulic unit, push on plug as the last step

If a control unit is damaged, the complete hydraulic unit together with integrated control unit must be replaced. Observe the following points:
- The control unit must be coded for the corresponding type of transmission.
- 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.
- The steering angle sensor must be recalibrated.

Rate-of-turn Sensor

CAUTION: The rate-of-turn sensor is a micro-mechanical component and is very sensitive to impacts.







Integrated in the rate-of-turn sensor is the transverse acceleration sensor.

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. Now 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.

Bleeding

DANGER: Danger of accident if there is air in the brake system.

The brake system may fail completely with total loss of braking effect.
- If the hydraulic part of the braking system has been opened, then the complete system must be bled.

The hydraulic unit can be bled using this menu item (secondary bleeding). Previously the brake system had to be bled by the conventional method (primary bleeding).

PROCEDURE:

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

1. Carry out primary bleeding.
2. Select the menu item 'Bleed' using the Porsche System Tester II No. 9588.
3. Confirm using appropriate key Yes/No and the >> key whether step 1 has been carried out.
4. Connect the Brake filling and bleeding device and pressures the brake system to approx. 2 bar pressure. Connect the brake fluid collecting container to the front right wheel.
5. Press the F8 'Start' key, open the front right bleeder valve and pump the brake pedal until bubble-free brake fluid emerges.
6. Close the front right bleeder valve and immediately press the >> key.
7. End the procedure with the << key.

Coding

Extract coding
The following items are displayed:

Steer-angle sensor calib. by: XXXXXXX
Version coded by: XXXXXXX
Veh. Ident. No. (e.g. 'WPOCA29843SOOOOOO')
Transmission: (e.g. 'Tiptronic/Boxster S')

NOTE: XXXXXXX -> The workshop number from the diagnosis card of the coding Porsche System Tester II No. 9588 is stored.

PROCEDURE:
1. Select the menu item 'Extract coding' using the Porsche System Tester II No. 9588.
2. End the procedure with the << key.

Modify coding

NOTE: The workshop number from the diagnosis card of the coding Porsche System Tester II No. 9588 is stored.

1. Select the menu item 'Modify coding' using the Porsche System Tester II No. 9588.
2. The Porsche System Tester II No. 9588 displays the current coding as follows:

Veh. Ident. No. (e.g. 'WPOCA29843SOOOOOO')
Transmission: (e.g. 'Tiptronic/Boxster S')

3. The display can be saved using the F4 key.
4. Select Veh. Ident. No. using the Up Arrow and Down Arrow keys.
5. Use the F8 key to continue. Use the Up Arrow and Down Arrow or -> and <- keys to enter the correct Veh. Ident. No. and confirm with the appropriate key Yes/No and >> key.
6. Code the input by pressing the F8 key and wait until the display 'Coding modified' appears.
7. End the procedure with the << key and use the Up Arrow and Down Arrow keys to select 'Transmission'.
8. Use the F8 key to continue. Select correct transmission type and the correct vehicle type using the Up Arrow and Down Arrow keys.
9. Code the selection by pressing the F8 key and wait until the display 'Coding modified' appears.
10. End the procedure with the << key.

Steering-Angle Sensor Calibration

NOTE: The steering-angle sensor must be re-calibrated after all work on the running gear.

The steering-angle sensor can be calibrated with this menu item. The security code is required for calibration of the steering-angle sensor. The security code is contained under menu item "Actual values".

PROCEDURE:

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

1. Set up vehicle on a running gear measuring platform and connect.
2. Carry out a complete check on the running-gear setting and correct as necessary; refer Suspension alignment, complete.
3. Use the Porsche System Tester II No. 9588 in the menu 'Actual values' to select the menu item 'Security code'. The four-figure code can be stored using the F4 key, but it is still advisable to note down the code.
4. End the procedure with the key sequence <<.
5. Select the menu item 'Calibrate steering angle sensor' using the Porsche System Tester II No. 9588.
6. Confirm using appropriate key Yes/No and the >> key whether step 3 has been carried out.
7. Use the Up Arrow and Down Arrow or -> and <- to enter the security code and confirm with the appropriate key Yes/No and >> key.
8. Wait until the display 'Calibration successfully changed' appears.
9. End the procedure with the << key.

NOTE:
- As of model year 2003, a new steering angle sensor is installed with a changed pin assignment for the electrical connection.
- The new steering angle sensor is retrospectively applicable to all vehicles with PSM. Vehicles before model year 2003 also require an adapter cable.
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