Pinpoint Test N : DTCS P0B0D:00, P0C27:00, P0C28:00, P0C29:00, P0C2A:00
- Refer to TRANSMISSION CONTROLS
for schematic and connector information.
Normal Operation and Fault Conditions
The transmission fluid auxiliary pump is used to keep the transmission fluid circulating during extended drive times without engine charging. The transmission fluid auxiliary pump has an internal microprocessor and communicates with the C1381E over a PWM circuit with a frequency of 150 Hz with a duty cycle range of 10% to 90%. If the transmission fluid level is low or overfilled or there are any restrictions in the transmission lines, hoses (If vehicle is equipped with external lines or hoses) or cooler it may affect the transmission fluid pump operation.
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition PCM P0B0D:00 Electric/Auxiliary Transmission Fluid Pump Motor Control Module: No Sub Type Information This DTC sets if the E-pump communication is OK. The frequency is between 130 Hz and 170 Hz and a valid duty cycle was detected (54% to 61% or 64% to 71%). The transmission fluid auxiliary pump has detected a pump over or under speed condition. The current flow through the pump was within specification. PCM P0C27:00 Electric/Auxiliary Transmission Fluid Pump "A" Motor Current Low: No Sub Type Information This DTC sets if the E-pump communication is OK. The frequency is between 130 Hz and 170 Hz and a valid duty cycle was detected (9% to 16%). The transmission fluid auxiliary pump has detected low current through the pump motor. The pump speed was within specification. PCM P0C28:00 Electric/Auxiliary Transmission Fluid Pump "A" Motor Current High: No Sub Type Information This DTC sets if the E-pump communication is OK. The frequency is between 130 Hz and 170 Hz and a valid duty cycle was detected (19% to 66%). The transmission fluid auxiliary pump has detected high current through the pump motor. The pump speed was within specification. PCM P0C29:00 Electric/Auxiliary Transmission Fluid Pump "A" Driver Circuit Performance: No Sub Type Information This DTC sets if the E-pump communication is OK. The frequency is between 130 Hz and 170 Hz and a valid duty cycle was detected (74% to 81%). The transmission fluid auxiliary pump has detected a performance issue with the pump driver. PCM P0C2A:00 Electric/Auxiliary Transmission Fluid Pump "A" Motor Stalled: No Sub Type Information This DTC sets if the E-pump communication is OK. The frequency is between 130 Hz and 170 Hz and a valid duty cycle was detected (35% to 41%). The transmission fluid auxiliary pump has detected 0 RPM pump speed. Possible Sources
- Connectors damaged or pushed-out terminals, corrosion, loose wires or ground and missing or damaged seals
- Fuse
- Transmission fluid auxiliary pump
- Incorrect fluid level
- PCM
Visual Inspection and Pre-checks
- Verify BJB fuse 49 is OK
- Verify BJB fuse 57 is OK
- N1 CHECK THE TRANSMISSION FLUID AUXILIARY PUMP POWER CIRCUITS
- Refer to the following table for DTC duty cycle ranges.
DTC Duty Cycle Range Description P0C2D Less than 9% Out of range low P0C27 9% to 16% Pump current too low, speed OK P0C28 19% to 26% Pump current too high, speed OK P175A 29% to 35% Pump over temperature P0C2A 35% to 41% Pump stalled None 44% to 51% Pump operating normally, signal range OK P0B0D 54% to 61% Pump over speed - current OK P0B0D 64% to 71% Pump under speed - current OK P0C29 74% to 81% Both current and speed out of range P2796 84% to 91% No Command received from Control Module P0C2E > 91% Duty Cycle Out of range HI - undefined P0C2C Any other value (between) Undefined duty cycle
- Ignition OFF.
- Disconnect Transmission Fluid Auxiliary Pump C1717.
- Ignition ON.
Is the voltage greater than 11 volts?
Yes GO to N2 No VERIFY the BJB fuses 49 and 57 are OK. If fuses are OK, REPAIR the affected circuit for an open. If fuses are not OK, REFER to the OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION to identify the cause of the affected circuit shorted to ground. - Refer to the following table for DTC duty cycle ranges.
- N2 CHECK THE TRANSMISSION FLUID AUXILIARY PUMP GROUND CIRCUIT FOR AN OPEN
- Measure:
Positive Lead Measurement / Action Negative Lead C1717-6 Ground
Is the resistance less than 3 ohms?
Yes GO to N3 No REPAIR the circuit - Measure:
- N3 CHECK THE TRANSMISSION FLUID LEVEL
- CHECK the transmission fluid level. REFER to: Transmission Fluid Level Check .
Is the transmission fluid level correct?
Yes If the vehicle is equipped with external lines, hoses going to the transmission fluid auxiliary pump, GO to N5 If not equipped with external lines, hoses, GO to N4 No CORRECT the transmission fluid to the proper level. - N4 CHECK THE TRANSMISSION FLUID LINES, HOSES AND COOLER
- Check the transmission fluid lines, hoses and transmission fluid cooler for obstructions or pinches (if equipped).
Are the transmission fluid lines, hoses and transmission fluid cooler free from obstructions or pinches?
Yes GO to N5 No REPAIR as necessary. - N5 CHECK THE TRANSMISSION FLUID AUXILIARY PUMP OPERATION
- Ignition ON.
- Using a diagnostic scan tool, COMMAND the transmission fluid auxiliary pump ON using PID, TRANS_PMP_CMD and vary the duty cycle from 20% to 90%,
Is the transmission fluid auxiliary pump operating and does the pump speed change as the duty cycle is increased or decreased?
Yes GO to N6 No INSTALL a new transmission fluid auxiliary pump. REFER to: Transmission Fluid Auxiliary Pump . - N6 RECHECK THE TRANSMISSION FLUID AUXILIARY PUMP OPERATION
- Attempt to duplicate concern.
- Clear diagnostic trouble codes (DTCs) and road test vehicle.
Are DTCS P0B0D:00, P0C27:00, P0C28:00, P0C29:00, P0C2A:00, and/or P175A present after the test drive?
Yes INSTALL a new transmission fluid auxiliary pump. REFER to: Transmission Fluid Auxiliary Pump . No The system is operating correctly at this time.