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Please read here for how to use our service (opens in a new tab).
The Function Control Unit (FCU) is responsible for controlling the 959's rear and centre limited slip differentials.
The typical repair price range for the FCU is £1,350 to £1,800GBP (exc. UK VAT) depending on what we discover during testing. We’ll let you know after test & diagnosis if the repair price is likely to exceed the lowest price stated above.
Turnaround time is 10 to 15 business days plus return shipping time. International customers welcome. More details here.
For more details regarding common faults and repairs with the FCU, please see ‘Additional Information’ on this page.
We are here to help, so if you have any questions, please contact us.
Porsche 959 Function Control Unit (FCU) repair service
This Function Control Unit (FCU) is responsible for the control of the 959's centre and rear differentials. It accepts input from the dashboard "drive select" switch and inputs from the Dual Pressure Actuator (DPA - hydraulics unit), the ABS Unit and TPMS unit. It manages the amount of torque transfer independently through the 2 differentials via the Output Control Unit (OCU). The ECU also undertakes adaptive control of the differentials based on road speed.
Fault symptoms include unit completely inoperable, the DPA hydraulic motors running with the ignition off, traction mode lights not working, traction mode control stalk not operating.
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