automatic transmission control module Genuine Porsche part 955618021BU

Porsche Cayenne Body Control Unit.



Fits:
Porsche 955 Cayenne 2003-06

Early Porsche cayenne's have a common issue where the rear washer pipe connector at the bottom of the drivers side A pillar breaks or comes apart then over time leaks over the body control unit.

The first signs of noticing the problem are that certain functions on the vehicle that this ECU controls stop working such as windows, wipers, lights etc. Normally because the water has shorted these circuits out and blown fuses.

As you get into diagnosing the faults and find the control unit isn't working as it should you disconnect the many plugs on the body control unit and you can see the water damaged caused by the leaking pipe.
After a while the small pins corrode so badly that they break.
You can see from our pictures the damage caused by the water and a couple of the pins are actually broken here also.

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95561802701

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Glow plug control unit.



Fits:
Porsche 957 Cayenne 3.0L DIESEL 2007-10
Porsche 958 Cayenne 3.0L DIESEL >>2011

Click 'Zoom in' for large parts diagram.
Diagram ref no 11

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95561802800

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Glow plug control unit.


Hella ref no 4RV 008 188-521

Fits:
Porsche 957 Cayenne 3.0L DIESEL 2007-10
Porsche 958 Cayenne 3.0L DIESEL >>2011

Click 'Zoom in' for large parts diagram.
Diagram ref no 11

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

95561802800

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Control unit diff lock longitudinal. 



Fits:
Porsche 955 Cayenne - 2005 to 2006

For cars with Option Code
G0R - Tiptronic S

Click 'Zoom in' for large parts diagram.
Diagram ref no 8



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95561802311

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Tiptronic Control Unit.
Restore proper centre differential/transfer-case lock control in your Porsche Cayenne 955 chassis, 2003-2004. This ECU module governs the longitudinal lock mechanism of the drive system, ensuring correct power distribution front to rear, correct 4WD behaviour and stable traction. Ideal for replacing a failed or malfunctioning unit, it enables your 4WD system to perform reliably.

Fits:

• Porsche 955 Cayenne 3.2L V6 2003-04
• Porsche 955 Cayenne S 4.5L V8 2003-04
• Porsche 955 Cayenne Turbo 4.5L 2003-04

Cars With Option Codes:
G0R - Tiptronic S

Diagram Ref No 8

What This Product Does:

• In 4WD/all-wheel-drive systems the “drive longitudinal lock” refers to locking mechanisms of the centre differential or transfer case — this ensures power is correctly distributed between front and rear axles.
• This ECU monitors and controls that locking system: it takes inputs (wheel speeds, differential states, driver commands) and commands the actuator (solenoids, clutches) in the transfer case or centre diff to engage or release the lock.
• Proper function ensures that the vehicle’s 4WD system behaves correctly (engaging or disengaging locks when required), which impacts traction, stability, driveability and sometimes road regulations (e.g., snow/ice mode).
• If this unit fails, the locking system can get stuck open or closed, produce fault codes, and affect driving behaviour (especially in low-traction or off-road situations).

Symptoms Of Failure Or Need For Replacement:

• A fault code related to the centre differential, transfer case, or “longitudinal lock” is present in the diagnostics.
• Loss of 4WD function or “lock” function — e.g., the vehicle stays in 2WD when it should lock, or it stays locked when it shouldn’t.
• Illumination of warning lamps related to drivetrain/4WD/traction.
• Unusual noises from the transfer case / centre diff (clutch slipping, grinding) that might be triggered by improper lock control.
• Intermittent behaviour (sometimes works, sometimes doesn’t) which can indicate ECU logic/actuator control failure rather than a purely mechanical fault.

Why Replacement Matters:

• Because the control unit is central to drivetrain behaviour, a fault here can drastically degrade vehicle performance, safety (traction/stability) and drivability.
• For a Porsche Cayenne early model (955), these units are becoming harder to source or may be superseded — replacing a failing unit proactively protects the vehicle.
• Restoring the correct function of the 4WD/centre differential lock restores the vehicle’s intended performance envelope, especially under load, off-road or in low-traction conditions.
• From a maintenance/resale perspective: a vehicle with a properly functioning transfer-case lock system is more desirable; faults here reduce value.
• Lastly, diagnosing and replacing the ECU early may prevent secondary damage (mechanical wear from improperly controlled locks/clutches).

Related reference numbers
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95561802305

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