A/T - Auxiliary Oil Pump, Test For DTC P0944
Auxiliary oil pump - test for fault code P0944Topic number LI27.57-P-053496
Version 1
Design group 27.57 Oil Pump
Date 04-05-2012
Validity NAG2 FE* with auxiliary oil pump
Reason for change
Complaint:
Attachment
ECO start/stop inoperative, fault code P0944 in transmission control unit.
Cause:
The check valve in torque converter housing may be damaged. Leakage between torque converter housing and auxiliary oil pump.
May affect transmissions with transmission sequence numbers starting with -07-xxx xxx.
Remedy:
Access via fault code P0944; and perform there the following test according to the instructions:
Check the check valve in the torque converter housing (in pressure duct) for damage (see pictures in attachment).
If the check valve is damaged, the torque converter housing and the auxiliary oil pump (component M42) must be replaced. When removing/installing the automatic transmission auxiliary oil pump, observe AR 27.30-P-0651EL.
Important note:
After the test/repair, check and correct the oil level in the transmission.
If no damage is found on the check valve, but a torque converter housing with object number 212 271 0401 is installed and the transmission sequence number is lower than 3.491.853, then please create a TIPS/PTSS case.
If the fault code is no longer present, perform the following test steps.
Step 1: Check connector and fuse of auxiliary oil pump
Step 2: Check supply voltage
Step 3: Check CAN lines
Step 4: Check VGS software and update if necessary, then continue with step 5
Step 5: Visual inspection of check valve; the valve is located in the torque converter housing (see pictures in attachment)
If the check valve is damaged, the torque converter housing and the auxiliary oil pump (component M42) must be replaced.
Step 6: Replace auxiliary oil pump
If one step resolves the problem, it is not necessary to continue with the remaining test steps. Exception: After step 4 always perform step 5.
Symptoms
Control Unit/Fault Code
Work Units
Attachment