Hi, I have just serviced my hitachi compressor, although there was no faults on it i thought it was time to give it a new lease of life, when running it for a few seconds it faulted out, checked all fuses were okay and the relay, and the compressor will run fine when crossing out the relay, i pulled the codes with sdd and got,

B1B78-84 HVAC SYSTEM PRESSURE.
U0428-86 ARCM INVALID DATA FROM STEERING ANGLE SENSOR MODULE.
O0434-86 RLM J_14229_DTC U0434.
C1A20-64 RLM J_14229_DTC C1A20.
U0421-94 ATCM INVALID DATA FROM RIDE LEVEL CONTROL MODULE.
U0159-87 IPC LOST COMMUNICATION WITH PARKING ASSIST MODULE

hvac i assume is aircon not cold enough so needs a regas

any Help on where i go from here most appreciated.

You may need a better fault code reader.

Obvious things

Have you put the 2 small pipes back the correct way.
Maybe you damaged the temperate sensor wires

Hi thanks for the reply,
i used dealer code reader jlr sdd to retrieve codes, pipes at the rear of the pump are different sizes so no way of mixing them up, pump runs fine crossing out the relay, its as if i am not getting the neg to feed the relay from the ecu.

Find out what those O and C codes mean then.
Search on here or
Disco3

Maybe you haven’t rebuilt it very well and made it worse then.

Or a problem with the pressure sensor. Where is it ?

Hi pump runs perfect when giving it direct power from the relay, looks to me that something is not giving the signal to the ecu to power the relay, where would i find the pressure sensor on the central valve block ? pump has got plenty of pressure when removing the dryer rear pipe, thanks for the reply.

the ecu isn't seeing a pressure increase at the sensor, so cuts the compressor off.

Hi, thanks again for your help, i removed the compressor again and removed the solenoid and it was cleaned out as the area was covered in dryer dust particles rebuilt the compressor and it seems fine now cleared fault codes but i still get as soon as i start up the message vehicle lean when cornering and amber light lit, car drives fine, pulled codes again and there is only 2 codes
B1B78-84 SYSTEM PRESSURE AS I NEED AIRCON RECHARGED (PERMANENT DTC)
U0159-87 LOST COMMUNICATION WITH PARKING ASSIST CONTROL MODULE (INTERMITTENT FAULT)
None of these codes will clear, i initially thought the lean when cornering was compressor fault or steering angle sensor but i recalibrated it successfully and fault is still there.

Maybe it is the hydraulic anti roll bars (ACE). I can't really help on them
Ensure you are reading the fault codes on all ECU's, so any ACE faults will be seen