Pinpoint Test E: Transmission Fluid Auxiliary Pump Circuit Diagnostics
- Refer to Wiring Diagrams TRANSMISSION CONTROLS - 10R80
for schematic and connector information.
Normal Operation and Fault Conditions
The transmission fluid auxiliary pump keeps the transmission fluid circulating and the transmission engaged during auto start-stop events. The transmission fluid auxiliary pump has an internal microprocessor and communicates with the PCM over a PWM circuit with a frequency of 150 Hz and a duty cycle range of 10% to 90%.
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition PCM P0C28:00 Electric/Auxiliary Transmission Fluid Pump "A" Motor Current High: No Sub Type Information This DTC indicates the transmission fluid auxiliary pump communication is OK, the frequency is between 125 Hz and 175 Hz, but a high current is detected (20% to 25% duty cycle). PCM P0C29:00 Electric/Auxiliary Transmission Fluid Pump "A" Driver Circuit Performance: No Sub Type Information This DTC indicates the transmission fluid auxiliary pump communication is OK, the frequency is between 125 Hz and 175 Hz, but a high current is detected and the pump speed is out of range (75% to 80% duty cycle) PCM P0C2A:00 Electric/Auxiliary Transmission Fluid Pump "A" Motor Stalled: No Sub Type Information This DTC indicates the PCM commanded the transmission fluid auxiliary pump on but did not detect a corresponding increase in pump speed, indicating a stalled pump motor (35% to 40% duty cycle). PCM P0C2C:00 Electric Transmission Fluid Pump Control Module Feedback Signal Range/Performance: No Sub Type Information This DTC indicates the transmission fluid auxiliary pump frequency is between 125 and 175Hz but has an invalid duty cycle, or the frequency is outside of the 125-175Hz range. This can be caused by a loss of power to the transmission fluid auxiliary pump. PCM P0C2D:00 Electric Transmission Fluid Pump Control Module Feedback Signal Low: No Sub Type Information This DTC indicates the transmission fluid auxiliary pump duty cycle is less than 10%. This DTC can set while using output state control to command a pump speed outside of normal operating parameters. PCM P0C2E:00 Electric Transmission Fluid Pump Control Module Feedback Signal High: No Sub Type Information This DTC indicates the transmission fluid auxiliary pump duty cycle is greater than 90%. This DTC can set while using output state control to command a pump speed outside of normal operating parameters PCM P2796:00 Electric Transmission Fluid Pump Control Circuit: No Sub Type Information This DTC indicates the transmission fluid auxiliary pump is not receiving a command signal from the PCM (85% to 90% duty cycle). Possible Sources
- Low transmission fluid level
- BJB fuse
- Connectors damaged or pushed-out terminals, corrosion, loose wires and missing or damaged seals
- Circuit open or shorted
- Transmission internal wiring harness
- Transmission fluid auxiliary pump
- PCM
- E1 CHECK THE TRANSMISSION FLUID LEVEL
- Check the transmission fluid level. REFER to: Transmission Fluid Level Check .
Is the transmission fluid level correct?
Yes GO to E2 No CORRECT the transmission fluid to the proper level, CLEAR the DTC and road test the vehicle. If the DTC returns, GO to E2 - E2 CHECK THE TRANSMISSION FLUID AUXILIARY PUMP VPWR CIRCUIT FOR VOLTAGE
- Ignition OFF.
- Disconnect Transmission vehicle harness C168A.
- Inspect the connector for damaged or pushed out terminals, corrosion, loose wires and missing or damaged seals.
- Ignition ON.
- Measure:
Positive Lead Measurement / Action Negative Lead C168A-10 Ground
Is the voltage greater than 11 volts?
Yes GO to E3 No VERIFY the BJB fuse F67 (20A) is OK. If the fuse is OK, REFER to the OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION to identify and repair an open circuit. If the fuse is not OK, REFER to the OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION to identify and repair a short to ground. - E3 CHECK THE TRANSMISSION FLUID AUXILIARY PUMP TASV CIRCUIT FOR VOLTAGE
- Ignition ON.
- Measure:
Positive Lead Measurement / Action Negative Lead C168A-12 Ground
Is the voltage greater than 11 volts?
Yes GO to E6 No GO to E4 - E4 CHECK THE TRANSMISSION FLUID AUXILIARY PUMP TASV CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect PCM C1381T.
- Inspect the connector for damaged or pushed out terminals, corrosion, loose wires and missing or damaged seals.
Is the resistance less than 3 ohms?
Yes GO to E5 No REPAIR the open circuit. - E5 CHECK THE TRANSMISSION FLUID AUXILIARY PUMP TASV CIRCUIT FOR A SHORT TO GROUND
- Measure:
Positive Lead Measurement / Action Negative Lead C168A-12 Ground
Is the resistance greater than 10, 000 ohms?
Yes Refer to PCM GUIDED ROUTINE TESTING
Internet Explorer version 11 or greater is required to perform this Pinpoint Test.
After programming the new PCM, CARRY OUT the transmission strategy download. REFER to: Transmission Strategy Download .No REPAIR the short to ground. - Measure:
- E6 CHECK THE TRANSMISSION FLUID AUXILIARY PUMP GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure:
Positive Lead Measurement / Action Negative Lead C168A-17 Ground
Is the resistance less than 3 ohms?
Yes GO to E7 No INSPECT ground G104. If the ground is clean and tight, REPAIR the open circuit. - E7 CHECK THE TRANSMISSION FLUID AUXILIARY PUMP ATFPC AND ATFPM CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect PCM C1381T.
- Inspect the connector for damaged or pushed out terminals, corrosion, loose wires and missing or damaged seals.
- Measure:
ATFPC
Positive Lead Measurement / Action Negative Lead C168A-18 C1381T-6 ATFPM
Positive Lead Measurement / Action Negative Lead C168A-19 C1381T-55
Are the resistances less than 3 ohms?
Yes GO to E8 No REPAIR the open circuit. - E8 CHECK THE TRANSMISSION FLUID AUXILIARY PUMP ATFPC AND ATFPM CIRCUITS FOR A SHORT TO GROUND
- Measure:
ATFPC
Positive Lead Measurement / Action Negative Lead C168A-18 Ground ATFPM
Positive Lead Measurement / Action Negative Lead C168A-19 Ground
Are the resistances greater than 10, 000 ohms?
Yes GO to E9 No REPAIR the short to ground. - Measure:
- E9 CHECK THE TRANSMISSION FLUID AUXILIARY PUMP ATFPC AND ATFPM CIRCUITS FOR A SHORT TO POWER
- Ignition ON.
- Measure:
ATFPC
Positive Lead Measurement / Action Negative Lead C168A-18 Ground ATFPM
Positive Lead Measurement / Action Negative Lead C168A-19 Ground
Is any voltage present?
Yes REPAIR the short to power. No GO to E10 - E10 CHECK THE TRANSMISSION CASE WIRING HARNESS ATFPC AND ATFPM CIRCUITS FOR AN OPEN
- Ignition OFF.
- Drain the transmission fluid and remove the transmission fluid pan. REFER to: Transmission Fluid Pan, Gasket and Filter .
- Disconnect Transmission Fluid Auxiliary Pump C1792.
- Inspect the connector for damaged or pushed out terminals, corrosion, loose wires and missing or damaged seals.
- Measure:
ATFPC
Positive Lead Measurement / Action Negative Lead C1792-4
Transmission component side, pin 18ATFPM
Positive Lead Measurement / Action Negative Lead C1792-5
Transmission component side, pin 19
Are the resistances less than 3 ohms?
Yes GO to E11 No INSTALL a new transmission case wiring harness. REFER to: Transmission Internal Wiring Harness . - E11 CHECK THE TRANSMISSION CASE WIRING HARNESS ATFPC AND ATFPM CIRCUITS FOR A SHORT TO GROUND
- Measure:
ATFPC
Positive Lead Measurement / Action Negative Lead C1792-4 Ground ATFPM
Positive Lead Measurement / Action Negative Lead C1792-5 Ground
Are the resistances greater than 10, 000 ohms?
Yes GO to E12 No INSTALL a new transmission case wiring harness. REFER to: Transmission Internal Wiring Harness . - Measure:
- E12 CHECK THE TRANSMISSION CASE WIRING HARNESS TRANSMISSION FLUID AUXILIARY PUMP POWER CIRCUITS
- Ignition OFF.
- Connect Transmission vehicle harness C168A.
- Connect PCM C1381T.
- Connect BJB fuse F67 (20A) (if previously disconnected).
- Ignition ON.
Are the voltages greater than 11 volts?
Yes GO to E13 No INSTALL a new transmission case wiring harness. REFER to: Transmission Internal Wiring Harness . - E13 CHECK THE TRANSMISSION INTERNAL WIRING HARNESS TRANSMISSION FLUID AUXILIARY PUMP GROUND CIRCUIT
- Ignition ON.
Is the voltage greater than 11 volts?
Yes INSTALL a new transmission fluid auxiliary pump. REFER to: Transmission Fluid Auxiliary Pump . No INSTALL a new transmission case wiring harness. REFER to: Transmission Internal Wiring Harness .