Fault Finding In Front Axle Lift System

Symptom	Fault detection	Possible causes	Solution
Body front section does not lift.	1.) Compressor is not running.	Electric fuse faulty.	Replace electric fuse.
		Control unit faulty.	Check whether a connection to the control unit can be established. If not, replace control unit 438155 REPLACING AIR-LIFT PUMP CONTROL UNIT .
		Compressor or electric lines faulty.	Check whether there is an electrical signal at the electric connector for the compressor. If there is, replace compressor 431519 REMOVING AND INSTALLING COMPRESSOR (FRONT AXLE LIFT SYSTEM) . If not, replace the relevant electric line.
	2.) Check separating couplings at the distributor/in the wheel housing	Separating coupling is not connected.	Connect separating coupling.
		Bent retaining clips on the separating coupling.	Replace the relevant pressure line.
	3.) Check emergency release valve on the compressor >Emergency release valve on compressor  .	Emergency release valve open.	Close emergency release valve.
	4.) Check components of the lift system for oil leaks.	Screws not tightened correctly.	Re-tighten screws >  WM, 4X00IN TIGHTENING TORQUES FOR PDCC/FRONT AXLE LIFT SYSTEM
		Component is leaking.	Replace the relevant component.
	5.) Check to see if pressure lines are crushed	Pressure line is crushed.	Replace pressure line.

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

Emergency release valve on compressor

1	Compressor
2	Emergency release valve (located behind stopper)

Symptom	Fault detection	Possible causes	Solution
Body front section lifts/lowers on one side only.	1.) Check separating coupling in the wheel housing.	Separating coupling is not connected.	Connect separating coupling.
		Bent retaining clips on the separating coupling.	Replace the relevant pressure line.
	2.) Check pressure lines for separating coupling at the actuator.	Pressure line is faulty.	Replace pressure line.
	3.) If no faults were found after carrying out Step 2.), the actuator is faulty	Actuator is faulty.	Replace actuator 408537 DISASSEMBLING AND ASSEMBLING FRONT SPRING STRUT .

Symptom	Fault detection	Possible causes	Solution
Body front section does not lower.	1.) Compressor is not running.	Electric fuse faulty.	Replace electric fuse.
		Control unit faulty.	Check whether a connection to the control unit can be established. If not, replace control unit 438155 REPLACING AIR-LIFT PUMP CONTROL UNIT .
		Compressor or electric lines faulty.	Check whether there is an electrical signal at the electric connector for the compressor. If there is, replace compressor 431519 REMOVING AND INSTALLING COMPRESSOR (FRONT AXLE LIFT SYSTEM) . If not, replace the relevant electric line.
	2.) Check separating couplings at the distributor/in the wheel housing	Separating coupling is not connected.	Connect separating coupling.
		Bent retaining clips on the separating coupling.	Replace the relevant pressure line.
	3.) Check to see if pressure lines are crushed	Pressure line is crushed.	Replace pressure line.