• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Transmission Pump Relay Coil Control | P0B09, P2796 | P0B09, P2796 | P0B09, P2796 | -- |
Transmission Pump Switch Control | P0B09, P2796 | P0B09, P2796 | P0B09, P2796 | -- |
Pump Control | P2796 | P2796 | P2796 | -- |
Pump Motor Voltage | P2796 | P2796 | P2796 | -- |
Transmission Pump High Reference | P2796 | P2796 | P2796 | -- |
Transmission Pump Low Reference | P2796 | P2796 | P2796 | -- |
Hybrid Pump Driver Ground | P2796 | P2796 | P2796 | -- |
The auxiliary transmission fluid pump is an electrical device that is used with the auxiliary transmission fluid pump relay to maintain transmission fluid line pressure to the transmission during Engine Idle Off mode. The ECM monitors the transmission fluid pressure switch (TFP) to verify that the auxiliary transmission pump is maintaining the proper amount of pressure. The auxiliary transmission fluid pump attaches to the transmission side cover assembly. The auxiliary transmission fluid pump relay receives voltage through the battery positive voltage circuit. The starter generator control module (SGCM) controls the auxiliary pump by providing the ground path on the auxiliary pump relay control circuit sending power to the Hybrid pump driver (HPD). The SGCM monitors all of the circuits of the auxiliary transmission fluid pump control circuits.
The Hybrid Wake Up signal is ON.
• | The SGCM detects an open, short to ground, or short to voltage on the auxiliary transmission fluid pump relay control circuit for 320 milliseconds. |
• | The SGCM detects an open, short to ground, or short to voltage on the Pump Control Circuit between the SGCM and the Hybrid Pump Driver for 320 milliseconds. |
SGCM detects an open or short to ground in any circuit of the auxiliary transmission fluid pump control circuit.
• | DTCs P0B09 and P2796 are Type B DTCs. |
• | The SGCM inhibits Auxiliary Transmission Pump Relay control. |
• | The SGCM inhibits auxiliary transmission fluid pump operation. |
• | The SGCM inhibits Hybrid operation. |
DTCs P0B09 and P2796 are Type B DTCs.
It is possible to have loose connectors at the HPD and the SGCM that may set these DTCs. Be sure connectors are fully engaged.
Starter/Generator Description and Operation
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
Ignition ON, command the transmission fluid pump relay ON and OFF with a scan tool. Listen for the auxiliary transmission fluid pump running and that the trans pump relay clicks. A stethoscope may be necessary to hear pump running.
⇒ | If the test lamp illuminates, test the relay controlled output circuit for a short to voltage. |
⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
⇒ | If the circuit tests normal and the B+ circuit fuse is open, test the relay coil control circuit for a short to ground. If the circuit tests normal, test or replace the Auxiliary Transmission Pump Relay. |
⇒ | If the test lamp does not illuminate, test the B+ circuit for an open/high resistance. |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If not within the specified range, replace the relay. |
• | 30 and 86 |
• | 30 and 87 |
• | 30 and 85 |
• | 85 and 87 |
⇒ | If not the specified value, replace the relay. |
⇒ | If greater than the specified range, replace the relay. |
⇒ | If greater than the specified range, test the pump control circuit for an open/high resistance. |
⇒ | If greater than the specified range, test the transmission pump driver error circuit for an open/high resistance. |
⇒ | If greater than the specified range, test the transmission pump driver error circuit for an open/high resistance. |
⇒ | If not within the specified range, replace the Auxiliary Trans Pump. |
⇒ | If greater than the specified range, test the transmission pump low and high reference circuits for an open/high resistance. |
⇒ | If the resistance is not within the specified range, replace the relay. |
• | 30 and 86 |
• | 30 and 87 |
• | 30 and 85 |
• | 85 and 87 |
⇒ | If not the specified value, replace the relay. |
⇒ | If greater than the specified range, replace the relay. |
Perform the Diagnostic Repair Verification after completing the repair.
• | Control Module References for SGCM or HPD replacement, setup, and programming. |