DTC Fault Trigger Conditions
DTC | Description | Fault Trigger Conditions |
|---|---|---|
P1889 | Oil Pressure Pump Performance | This DTC sets in continuous memory when the differential oil temperature exceeds system capability due to blockage, a component failure or system failure. |
P188A Differential Oil Temperature Too High / Too Low | This DTC sets in continuous memory when the differential oil temperature exceeds 145° C (293° F). |
Possible Causes
Restricted air flow through the differential oil cooler Restricted oil flow through the differential oil cooler system Wiring, terminals or connectors Differential oil pump relay Differential oil temperature sensor Differential oil pump
Visual Inspection and Diagnostic Pre-checks
Make sure the differential oil is at the correct level. Make sure the differential and differential cooler system are free of any leaks. Make sure there are no air flow blockages or restrictions through the oil cooler.
PINPOINT TEST B : DTC P1889 OR P188A
B1 CHECK FOR OTHER PCM DTCS
Ignition ON. Using a scan tool, carry out the PCM KOEO self-test.
Is DTC P1888 or P188E present?
Yes | For DTC P1888, GO to Pinpoint Test A For DTC P188E, GO to Pinpoint Test C | |
|---|---|---|
No | For all other PCM DTCs, REFER to: Electronic Engine Controls (303-14C Electronic Engine Controls - 5.0L 32V Ti-VCT/5.0L Ti-VCT V8 (308kW/418PS), Diagnosis and Testing). If no other PCM DTCs are present, GO to B2 | |
B2 CHECK THE DIFFERENTIAL OIL PUMP OPERATION
Using a scan tool, toggle the rear differential fluid pump (R_DIFF_PUMP)PID ON.
Does the pump motor run?
Yes | TOGGLE the R_DIFF_PUMP PID OFF. GO to B3 | |
|---|---|---|
No | TOGGLE the R_DIFF_PUMP PID OFF. GO to Pinpoint Test D | |
B3 CHECK THE DIFFERENTIAL COOLER SYSTEM FOR BLOCKAGES AND RESTRICTIONS
2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.