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When Monitored:
When Powertrain Control Module initially powers up. Due to the integration of the Powertrain and Transmission
Control Modules, the transmission part of the PCM has its own specific power and ground circuits.
Set Condition:
This DTC will set if the PCM powers up and senses the vehicle in a valid forwardgear,withnoPRNDLDTCs,
and an output speed above 800 RPM, approximately 32 Kmh or 20 mph.
Possible Causes
POWER UP AT SPEED
Always perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting Procedure before proceeding. (Refer to
21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
Theory of Operation
If a vehicle loses power to the Transmission Control System, the solenoids(LR, 2C, OD, UD, 4C) will go to their
respective power off state. Some solenoids are normally vented and some are normally applied in their power off
state. The transmission is designed to be in 3rd gear with all of the solenoids in this state. However, if power is
restored, the Transmission Control System will power-up and normal operation will be restored.
This code identifies that power to the Transmission Control System was restored when the gear selector was in a
Driveposition while the vehicle was moving at speeds above 32 Kmh (20 mph).This DTC does not indicate a
problem with the transmission or Transmission Control System,instead, it suggests intermittent problems in
the fused ignition switch output, fused B(+), or ground circuits to the TCM. Alternately, if a person performs a rolling
restart maneuver, the DTC can be set. Therefore it is critical that this DTCbe investigated if the vehicle is experi-
encing intermittent 3rd gear operation and a subsequent return to normal operation.
Diagnostic Test
1.CHECK THE POWER AND GROUND CIRCUITS
This DTC is set when the Transmission portion of the Powertrain Control Module is initialized while the vehicle is
movingdowntheroadinavalidforwardgear.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
NOTE: Due to the integration of the Powertrain and Transmission Control Modules, the transmission part of
the PCM has its own specific power and ground circuits.
Check all of the Fused B(+), Fused Ignition Switch Output, and ground circuits to the PCM for an intermittent open
or short to ground.
With the scan tool, check the DTC EVENT DATA to help identify the conditionsin which the DTC was set.
View repair.
Repair
Check all power and ground circuits to the PCM and repair as necessary.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
Page 3272 of 5267
P0890-SWITCHED BATTERY
For a complete wiring diagramRefer to Section 8W.
Page 3276 of 5267
P0932-LINE PRESSURE SENSOR CIRCUIT
For a complete wiring diagramRefer to Section 8W
Page 3279 of 5267
P0934-LINE PRESSURE SENSOR CIRCUIT LOW
For a complete wiring diagramRefer to Section 8W.
Page 3284 of 5267
P0935-LINE PRESSURE SENSOR CIRCUIT HIGH
For a complete wiring diagramRefer to Section 8W
Page 3289 of 5267

P0944-LOSS OF HYDRAULIC PUMP PRIME
For a complete wiring diagramRefer to Section 8W
When Monitored:
If the transmission is slipping in any forward gear and all the pressure switches are not indicating pressure, a
loss of prime test is run.
Set Condition:
If the transmission begins to slip in a forward gear and all the pressure switch(s) that should be closed are
open a loss of prime test begins. Available elements are turned on by the PCMto see if pump prime exists.
The DTC sets if no pressure switch(s) respond.
Possible Causes
SHIFT LEVER OUT OF ADJUSTMENT
IMPROPER FLUID LEVEL
CRACKED OR IMPROPERLY INSTALLED PRIMARY OIL FILTER OR SEAL
LOOSE COOLER RETURN FILTER
STUCK OR STICKING MAIN REGULATOR VALVE
TRANSMISSION OIL PUMP
Always perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to
21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
Theory of Operation
The Loss of prime test is used to prevent transmission defaults and erroneous fault codes during temporary loss of
pump prime that may occur with low transmission fluid under severe brakingconditions, start-up, etc. and to point
towards more subtle problems such as a plugged or cracked oil filter.
The Loss of Prime DTC is set by a loss of hydraulic pressure in the transmission system. This condition, if sus-
tained, will result in the vehicle being unable to move.
Diagnostic Test
1.SHIFT LEVER POSITION TEST
Using the scan tool, perform a Shift Lever Position test. Follow the instructions on the scan tool.
Did the Shift Lever Position Test pass?
Ye s>>
Go To 2
No>>
Refer to the Transmission category and perform the appropriate symptom.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
2.CHECK TO SEE IF DTC P0944 IS CURRENT
Place the gear selector in Park.
Start the engine.
The transmission must be at operating temperature prior to checking pressure. A cold transmission will give higher
readings.
Run the engine at 1500 RPM.
With the scan tool, monitor the Transmission Line Pressure.
Does the Line Pressure match the Desired Line Pressure within ± 5 psi?
No>>
Go To 6
Ye s>>
Go To 3
Page 3291 of 5267
P0987-4C HYDRAULIC PRESSURE TEST
For a complete wiring diagramRefer to Section 8W.
Page 3299 of 5267
P0988-4C PRESSURE SWITCH RATIONALITY
For a complete wiring diagramRefer to Section 8W