Buick Regal: DTC C1244, C1245, or C124B

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC C1244

AWD Oil Pump Motor Speed Sensor Supply Circuit Low Voltage

DTC C1245

AWD Oil Pump Motor Speed Sensor Supply Circuit High Voltage

DTC C124B

AWD Oil Pump Motor Speed Sensor Signal Circuit Erratic

For symptom byte information, refer to Symptom Byte List.

Diagnostic Fault Information

Circuit/System Description

The rear differential clutch control module monitors the speed of the AWD oil pump motor by using a hall effect sensor which is internal to the differential clutch pump. The sensor is a transducer that varies its output voltage in response to a magnetic field.

Conditions for Running the DTC

C1244 00, C1245 00, C124B 00

• The engine is running.
• Battery voltage is between 9-16 V.
• The engine speed is above 400 rpm.

Conditions for Setting the DTC

C1244 00

The AWD oil pump motor speed sensor supply circuit voltage is below 1.0 V.

C1245 00

The AWD oil pump motor speed sensor supply circuit voltage is above 6.0 V.

C124B 00

A plausibility error is detected on the AWD oil pump motor speed sensor signal circuit.

Action Taken When the DTC Sets

• Electronic limited slip is disabled for the duration of the key cycle.
• The AWD SERVICE message is displayed in the driver information center.

Conditions for Clearing the DTC

• The condition for the DTC is no longer present.
• The DTC is not detected in 40 consecutive ignition cycles.

Reference Information

Schematic Reference

Rear Axle Wiring Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEW INDEX

Description and Operation

Rear Drive Axle Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the M32 Differential Clutch Pump. It may take up to 2 min for all vehicle systems to power down.

2. Test for less than 10 Ω between the low reference circuit terminal 5 and ground.

• If 10 Ω or greater

1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module.
2. Test for less than 2 Ω in the low reference circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K47 Rear Differential Clutch Control Module.

• Go to next step: If less than 10 Ω

3. Ignition ON/Vehicle in Service Mode.

4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 1 and ground.

• If less than 4.8 V

1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module.
2. Test for infinite resistance between the 5 V reference circuit and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • Go to next step: If infinite resistance
3. Test for less than 2 Ω in the 5 V reference circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K47 Rear Differential Clutch Control Module.

• If greater than 5.2 V

1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module, Ignition ON/Vehicle in Service Mode.
2. Test for less than 1 V between the 5 V reference circuit and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • If less than 1 V, replace the K47 Rear Differential Clutch Control Module.

Go to next step: If between 4.8 - 5.2 V

5. Test for 4.8 - 5.2 V between the signal circuit terminals listed below and ground.

• Signal Circuit Terminal 2
• Signal Circuit Terminal 3
• Signal Circuit Terminal 4
• If less than 4.8 V

1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module.
2. Test for infinite resistance between the appropriate signal circuit terminal and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • Go to next step: If infinite resistance
3. Test for less than 2 Ω in the appropriate signal circuit terminal end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K47 Rear Differential Clutch Control Module.

• If greater than 5.2 V

1. Ignition OFF, disconnect the X2 harness connector at the K47 Rear Differential Clutch Control Module, Ignition ON/Vehicle in Service Mode.
2. Test for less than 1 V between the appropriate signal circuit terminal and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • If less than 1 V, replace the K47 Rear Differential Clutch Control Module.

• Go to next step: If between 4.8 - 5.2 V

6. Test or replace the M32 Differential Clutch Pump.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Differential Carrier Assembly Replacement
• Control Module References for control module replacement, programming and setup.

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