• | 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 |
---|---|---|---|---|
Trans. Aux. Oil Pump Control | P2797 | P2797 | P2797 | -- |
Trans. Aux. Oil Pump Diagnostic | P0C2B | P0C2B | P0C2B | P0C2B |
Condition | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Ignition ON Parameter Normal Range: OK | |||
Trans. Aux. Oil Pump Control | PWM Input Fault | PWM Input Fault | PWM Input Fault |
Condition | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Ignition ON Parameter Normal Range: OK | |||
Trans. Aux. Oil Pump Diagnostic | PWM Failure | PWM Failure | PWM Failure |
The auxiliary transmission fluid pump (ATFP) system supplies the transmission with hydraulic pressure when the vehicle is operating in the internal combustion engine (ICE) Autostop hybrid mode. The ATFP system consists of a ATFP control module that operates an electric, 12V 3 phase alternating current (ac), motor-driven pump. Two pulse width modulated (PWM) status circuits connect the ATFP control module to the hybrid powertrain control module (HPCM). The transmission auxiliary oil pump (TAOP) control circuit delivers the HPCM commanded pump speed to the ATFP control module. The transmission auxiliary oil pump (TAOP) diagnostic circuit supplies the HPCM with the actual pump speed and also with the operating status of the ATFP control module. The HPCM monitors these circuits for fault conditions.
The ATFP control module inverts 12 v direct current (dc) into 12 v, 3 phase ac current to operate the pump motor.
The ATFP control module monitors the status of the ATFP pump as well as its own internal circuitry. The ATFP control module does not store its own diagnostic status. Current ignition cycle diagnostic status is reported to the HPCM on the TAOP diagnostic circuit. The diagnostic status within the ATFP control module is reset at every ignition-off cycle.
• | The vehicle is operating in the Autostop hybrid mode. |
• | Ignition voltage is 8-18 volts. |
The control module has not detected the ATFP diagnostic signal for 1.5 seconds.
• | DTC P0C2B is a Type B DTC. |
• | The HPCM disables the Autostop hybrid mode. |
DTC P0C2B is a Type B DTC.
The engine harness connector for the ATFP control module and the mating connector for the transmission auxiliary pump motor can be improperly connected to each other. The following conditions may be observed if the improper connectors are mated together:
• | DTC P0C2B |
• | The TRANS PUMP 60A fuse will open |
• | BCM DTC B1433 |
• | Air conditioning system does not blow cold air |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
J 38522 Variable Signal Generator
Important: Ensure the engine harness connector is properly mated to the ATFP control module and the transmission auxiliary pump motor is properly mated to the ATFP control module before continuing with circuit/system testing. Refer to Diagnostic Aids.
⇒ | If less than battery voltage, test the ATFP battery circuit for an open/high resistance. If the circuit tests normal, continue with diagnosis. |
Important: If an open ground condition is observed, inspect the 3 phase motor shield circuit and terminal for damage.
⇒ | If less than the specified range, test the ATFP ground circuit for an open/high resistance. If the circuit tests normal, continue with diagnosis. |
⇒ | If less than the specified range, test the ATFP ignition circuit for an open/high resistance. If the circuit tests normal, continue with diagnosis. |
⇒ | If less than the specified range, test the Trans. Aux. Oil Pump Diagnostic circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the PIM. |
⇒ | If more than the specified range, test the Trans. Aux. Oil Pump Diagnostic circuit for a short to voltage. If the circuit tests normal, replace the PIM. |
⇒ | If less than 100 percent, test the Trans. Aux. Oil Pump Diagnostic circuit for a short to 5V. If the circuit tests normal, replace the PIM. |
⇒ | If 100 percent is displayed, replace the ATFP control module. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for PIM or ATFP control module replacement, setup, and programming