P0C2B
DTC P0C2B
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P0C2B
- Auxiliary Transmission Fluid Pump Control Feedback Circuit
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The auxiliary transmission fluid pump system supplies the transmission with hydraulic pressure when the vehicle is operating in the internal combustion engine Autostop hybrid mode. The auxiliary transmission fluid pump system consists of a auxiliary transmission fluid pump control module that operates an electric, 12V 3 phase alternating current (AC), motor-driven pump. Two pulse width modulated (PWM) status circuits connect the auxiliary transmission fluid pump control module to the hybrid powertrain control module. The transmission auxiliary oil pump control circuit delivers the hybrid powertrain control module commanded pump speed to the auxiliary transmission fluid pump control module. The transmission auxiliary oil pump diagnostic circuit supplies the hybrid powertrain control module with the actual pump speed and also with the operating status of the auxiliary transmission fluid pump control module. The hybrid powertrain control module monitors these circuits for fault conditions.
The auxiliary transmission fluid pump control module inverts 12V direct current (DC) into 12V, 3 phase ac current to operate the pump motor.
The auxiliary transmission fluid pump control module monitors the status of the auxiliary transmission fluid pump motor/pump as well as its own internal circuitry. The auxiliary transmission fluid pump control module does not store its own diagnostic status. Current ignition cycle diagnostic status is reported to the hybrid powertrain control module over the transmission auxiliary oil pump diagnostic circuit. The diagnostic status within the auxiliary transmission fluid pump control module is reset at every ignition-off cycle.
Conditions for Running the DTC
* The ignition voltage is 8-18 volts.
* The ignition is ON.
Conditions for Setting the DTC
The hybrid powertrain control module has not detected an auxiliary transmission fluid pump control module diagnostic signal for at least 1.5 seconds.
Action Taken When the DTC Sets
* DTC P0C2B is a Type B DTC.
* The drive motor generator power inverter module disables the Autostop function of the hybrid system.
Conditions for Clearing the DTC
DTC P0C2B is a Type B DTC.
Diagnostic Aids
The engine harness connector for the auxiliary transmission fluid pump control module and the mating connector for the transmission auxiliary pump motor can be improperly connected to each other. All of 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
The auxiliary transmission fluid pump control module monitors the status of the auxiliary transmission fluid motor/pump as well as its own internal circuitry. This control module does not store its own diagnostic status. Diagnostic status for the current ignition cycle is reported to the hybrid powertrain control module. The diagnostic status within the auxiliary transmission fluid pump control module is reset at every ignition-off cycle.
To determine if a fault is present, while commanding the aux. trans. fluid pump speed to 50 percent observe the hybrid powertrain control module Aux. Trans. Fluid Pump Fault Status 1 and the hybrid powertrain control module Aux. Trans. Fluid Pump Fault Status 2 parameters. Both readings should display No Fault.
Below is the fault status that will be reported if a fault condition is current.
No PWM Response
This fault status indicates the hybrid powertrain control module does not detect the automatic transmission auxiliary fluid pump Control Feedback circuit signal.
Reference Information
Schematic Reference
Hybrid Controls Schematics Hybrid Controls Schematics
Connector End View Reference
Component Connector End Views Connector Views
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Special Tools
J 38522 - Variable Signal Generator
For equivalent regional tools, refer to Special Tools Tools and Equipment.
Circuit/System Verification
1. Verify that DTC B1433 is not set.
• If the DTC is set, refer to DTC B1433 B1433.
2. Ignition ON, engine OFF, command the Aux. Trans. Pump Speed to 50 percent with the scan tool, maintain pump operation for at least 60 seconds while observing the hybrid powertrain control module aux. trans. fluid pump actual and the aux. trans. fluid pump commanded parameter. The actual parameter should remain within 10 percent of commanded value during the 60 second test.
• If not within the specified range, refer to Circuit System Testing.
3. While commanding the aux. trans. fluid pump speed to 50 percent observe and record the hybrid powertrain control module Aux. Trans. Fluid Pump Fault Status 1 and the hybrid powertrain control module Aux. Trans. Fluid Pump Fault Status 2 parameters. Both readings should display No Fault.
• If the reading displays No PWM Response, refer to Circuit System Testing.
Circuit/System Testing
1. Ignition OFF, disconnect the X1 harness connector at the K6 automatic transmission auxiliary fluid pump control module.
2. Test for less than 5 ohm between the ground circuit terminal C and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Verify that a test lamp illuminates between the B+ circuit terminal A and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal E and ground.
• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
5. Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal D and ground.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K6 automatic transmission auxiliary fluid pump control module.
• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the T6 drive motor generator power inverter module.
6. Ignition OFF. Disconnect the X1 harness connector at the K6 automatic transmission auxiliary fluid pump control module. Connect the J 38522 - variable signal generator to the harness connector signal circuit terminal D and ground.
7. Adjust the signal generator to 50 percent duty cycle @ 250 Hz and observe the Trans. Aux. Pump Actual parameter with the scan tool. The scan tool should display 100 percent.
• If the reading is less than 100 percent, test the signal circuit for a short to voltage. If the circuit tests normal replace the T6 drive motor generator power inverter module.
8. If the reading is 100 percent, replace the K6 automatic transmission auxiliary fluid pump control module.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
Control Module References Control Module References for Drive Motor Generator Power Inverter Module or Automatic Transmission Auxiliary Fluid Pump Control Module replacement, setup, and programming