When Monitored:
Continuously with the ignition on and engine running.
Set Condition:
The DTC will set if the LR Pressure Switch reads open or closed at the wrong time in a given gear.
Possible Causes
LOSS OF PRIME AND/OR TIPM DTC PRESENT
LOW FLUID LEVEL
LOW LINE PRESSURE
REVERSE CARRIER SNAP RING DISLODGED
CRACKED OR MISINSTALLED PRIMARY OIL FILTER OR FILTER SEAL
STICKING MAIN REGULATOR VALVE IN PUMP VALVE BODY
NO. 1 CHECK BALL CUT OR DAMAGED
WIRING AND CONNECTORS
(T50) LR PRESSURE SWITCH SENSE CIRCUIT OPEN
(T50) LR PRESSURE SWITCH SENSE CIRCUIT SHORT TO GROUND
(T50) LR PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
TRANSMISSION SOLENOID/TRS ASSEMBLY
POWERTRAIN CONTROL MODULE
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 Transmission system uses five pressure switches to monitor the fluid pressure in the LR, 2C, 4C, UD, and OD
clutch circuits. The pressure switches are continuously monitored for the correct states in each gear as shown.
GEAR L/R 2C 4C UD OD
REVERSEOPEN OPEN OPEN OPEN OPEN
P/NCLOSED** OPEN OPEN OPEN OPEN
1STCLOSED* OPEN OPEN CLOSED OPEN
2NDOPEN CLOSED OPEN CLOSED OPEN
2ND PRIMEOPEN OPEN CLOSED CLOSED OPEN
3RDOPEN OPEN OPEN CLOSED CLOSED
4THOPEN OPEN CLOSED OPEN CLOSED
5THOPEN CLOSED OPEN OPEN CLOSED
*L/R is closed if output speed is below 100 rpm in Drive and Manual 2. L/R is closed in Manual 1.
**May be open when rolling in Neutral or at low oil temperatures.
Diagnostic Test
1.CHECK IF OTHER RELATED DTC’S PRESENT
Ignition on, engine not running.
With the scan tool, check for other transmission DTC’s.
Are there any Loss of Prime and/or TIPM TCM related DTCs present?
Ye s>>
Refer to the Transmission category and perform the appropriate symptom. If the DTC P0944 is present,
perform its respective test first.
No>>
Go To 2
12.CHECK THE PCM POWERS AND GROUNDS
Using the schematics as a guide, check the Powertrain Control Module (PCM)terminals for corrosion, damage, or
terminal push out. Pay particular attention to all power and ground circuits.
Were there any problems found?
Ye s>>
Repair as necessary.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Go To 13
13.ROAD TEST THE VEHICLE
With the scan tool, clear the DTC and road test the vehicle.
Try to duplicate the conditions in which the DTC originally set using the DTC EVENT DATA recorded earlier.
Did the DTC P0841 reset?
Ye s>>
Using the schematics as a guide, check the Powertrain Control Module (PCM)terminals for corrosion,
damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems
are found, replace the PCM per the Service Information. With the scan tool,perform QUICK LEARN.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Go To 17
14.CHECK FOR LOW LINE PRESSURE
In the DTC EVENT DATA recorded earlier,compare the Line Pressure and the Desired Line Pressure.
Is the Line Pressure less than 40 psi, and significantly below the Desired Line Pressure?
Ye s>>
Repair as necessary to correct low line pressure. Check for low fluid level. Check the Primary Oil Filter
seal for a split, crack, or improperly installed. Refer to the Service Information for the proper installation
procedure. If the fluid level and Primary Oil Filter are OK, check the Main Regulator Valve in the Oil
Pump per the Service Information.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Go To 15
15.CHECK THE (T50) LR PRESSURE SWITCH SENSE CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT
Turn the ignition off to the lock position.
Disconnect the Transmission Solenoid/TRS Assembly harness connec-
tor.
Disconnect all PCM harness connectors.
Measure the resistance between the (T50) LR Pressure Switch Sense
circuit and all other circuits in the Transmission Solenoid/TRS Assembly
harness connector.
Is the resistance below 5.0 ohms between the (T50) LR Pres-
sure Switch Sense circuit and any other circuit(s) in the Trans-
mission Solenoid/TRS Assembly harness connector?
Ye s>>
Repair the (T50) LR Pressure Switch Sense circuit for a
short to another circuit(s).
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
No>>
Go To 16
When Monitored:
In any forward gear with engine speed above 1000 RPM shortly after a shift and every minute thereafter.
Set Condition:
After a shift into a forward gear, with engine speed above 1000 RPM, the PCM momentarily turns on element
pressure to the Clutch circuits that don’t have pressure to identify the correct Pressure Switch closes. If the
Pressure Switch does not close 2 times, the DTC sets.
Possible Causes
LINE PRESSURE SENSOR
TRANSMISSION FLUID CONTAMINATION
RELATED TIPM TCM DTCS PRESENT
RELATED DTC’S PRESENT
TRANSMISSION SOLENOID/TRS ASSEMBLY
EXCESSIVE DEBRIS IN OIL PAN
POOR LINE PRESSURE SENSOR CONNECTION
(T147) 2C PRESSURE SWITCH SENSE CIRCUIT OPEN
(T147) 2C PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
(T147) 2C PRESSURE SWITCH SENSE CIRCUIT SHORT TO ANOTHER CIRCUIT
(F856) 5-VOLT SUPPLY CIRCUIT OPEN
(T147) 2C PRESSURE SWITCH SENSE CIRCUIT SHORT TO GROUND
(F856) 5-VOLT SUPPLY CIRCUIT SHORT TO GROUND
TRANSMISSION SOLENOID/TRS ASSEMBLY
INTERNAL TRANSMISSION
POWERTRAIN CONTROL MODULE
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 Transmission Control System tests the pressure switches when they areoff. The test verifies that the switches
are operational (They will close with pressure applied). The Transmission Control System verifies that the switch
closes when the corresponding element is applied. If a switch fails to close, it is re-tested. If it fails the second test,
the DTC will set, the MIL will illuminate and the transmission system will default to the orderly Shutdown routine.
Diagnostic Test
1.DETERMINING IF RELATED DTC’S ARE PRESENT
With the scan tool, check for other transmission DTCs.
Is there any Loss of Prime, TIPM TCM Power Input , and/or Line Pressure Sensor DTCs present?
Ye s>>
Refer to the Transmission category and perform the appropriate symptom. If the DTC P0944-LOSS OF
PRIME is present, perform its respective test first.
No>>
Go To 2
16.CHECK THE (T147) 2C PRESSURE SWITCH SENSE CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT
Disconnect all PCM harness connectors.
Disconnect the Transmission Solenoid/TRS Assembly harness connec-
tor.
NOTE: Make sure the Transmission Solenoid/TRS Assembly har-
ness connector is disconnected.
Measure the resistance between the (T147) 2C Pressure Switch Sense
circuit and all other circuits in the Transmission Solenoid/TRS Assembly
harness connector.
Is the resistance below 5.0 ohms between the (T147) 2C Pres-
sure Switch Sense circuit and any other circuit(s) in the Trans-
mission Solenoid/TRS Assembly harness connector?
Ye s>>
Repair the (T147) 2C Pressure Switch Sense circuit for a
short to another circuit(s).
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1.
No>>
Using the schematics as a guide, check the Powertrain Control Module (PCM)terminals for corrosion,
damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems
are found, replace the PCM per the Service Information. With the scan tool,perform QUICK LEARN.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
17.INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specifictothiscircuit.
Wiggle the wires while checking for shorted and open circuits.
With the scan tool, check the DTC EVENT DATA to help identify the conditionsin which the DTC was set.
If the DTC EVENT DATA shows the DTC P0845 set while the Line Pressure was significantly below the Desired
Line Pressure reading, check for causes of low line pressure (low fluid level, broken or mis-installed primary oil filter
or filter seal, sticking Main Regulator Valve in the Pump Valve Body etc.).IfthedatashowstheDTCsetwhilethe
Line Pressure reading was significantly higher than the Desired Line Pressure, check the Line Pressure Sensor and
related wiring.
Where there any problems found?
Ye s>>
Repair as necessary.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .
When Monitored:
Continuously with the ignition on, engine running, with the transmissionin gear.
Set Condition:
The DTC is set if the 2C Pressure Switchreadsopenorclosedatthewrongtimein a given gear.
Possible Causes
RELATED TIPM TCM DTCS PRESENT
(T147) 2C PRESSURE SWITCH SENSE CIRCUIT OPEN
(T147) 2C PRESSURE SWITCH SENSE CIRCUIT SHORT TO GROUND
(T147) 2C PRESSURE SWITCH SENSE CIRCUIT SHORT TO OTHER CIRCUITS
EXCESSIVE FLUID LEAKAGE IN 2C CLUTCH CIRCUIT
NO. 5 AND/OR NO. 7 CHECK BALL CUT OR DAMAGED
EXTRA CHECK BALL DOWNSTREAM OF THE NO. 7 CHECK BALL SOCKET
LOW LINE PRESSURE
TRANSMISSION SOLENOID/TRS ASSEMBLY
POWERTRAIN CONTROL MODULE
WIRING AND CONNECTORS
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 Transmission system uses five pressure switches to monitor the fluid pressure in the LR, 2C, 4C, UD, and OD
clutch circuits. The pressure switches are continuously monitored for the correct states in each gear as shown.
GEAR L/R 2C 4C UD OD
REVERSEOPEN OPEN OPEN OPEN OPEN
P/NCLOSED** OPEN OPEN OPEN OPEN
1STCLOSED* OPEN OPEN CLOSED OPEN
2NDOPEN CLOSED OPEN CLOSED OPEN
2ND PRIMEOPEN OPEN CLOSED CLOSED OPEN
3RDOPEN OPEN OPEN CLOSED CLOSED
4THOPEN OPEN CLOSED OPEN CLOSED
5THOPEN CLOSED OPEN OPEN CLOSED
*L/R is closed if output speed is below 100 rpm in Drive and Manual 2. L/R is closed in Manual 1.
**May be open when rolling in Neutral or at low oil temperatures.
Diagnostic Test
1.CHECK FOR TCM TIPM DTCS
With the scan tool under TIPM, check for TCM Power Input DTCs.
Are there any TIPM TCM Power Input DTCs present?
Ye s>>
Refer to the Transmission category and perform the appropriate symptom. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.CHECK IF THE DTC DATA SHOWS THE CURRENT DTC
With the scan tool, check the DTC EVENT DATA.
Does the DTC EVENT DATA show data for DTC P0846?
Ye s>>
Go To 3
No>>
Refer to the Transmission category and perform the appropriate symptom shown in the DTC EVENT
DATA.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
3.CHECK IF MULTIPLE DTCS ARE PRESENT
With the scan tool, check for other transmission DTC’s.
Are there two or more related pressure switch rationality DTCs present in addition to P0846?
Ye s>>
Go To 4
No>>
Go To 7
4.CHECK IF ALL THE PRESSURE SWITCHES READ CLOSED
With the scan tool, check the DTC EVENT DATA for P0846.
NOTE: Make sure to record all DTC EVENT DATA stored in the scan tool for future reference in this test
procedure.
Do all the pressure switches read CLOSED in the DTC EVENT DATA for P0846?
Ye s>>
Refer to Transmission category and perform diagnostics for P0888.
No>>
Go To 5
5.CHECK IF ALL THE PRESSURE SWITCHES READ OPEN
In the DTC EVENT DATA recorded earlier,read the state of all pressure switches.
Do all the pressure switches read OPEN?
Ye s>>
Go To 6
No>>
Go To 7
6.CHECK FOR LOW LINE PRESSURE
In the DTC EVENT DATA recorded earlier,compare the Line Pressure and the Desired Line Pressure.
Is the Line Pressure less than 40 psi, and significantly below the Desired Line Pressure?
Ye s>>
Repair as necessary to correct low line pressure. Check fluid level and adjustasnecessary.Iffluidlevel
is OK, check the Primary Oil Filter seal for a split, crack, or improperly installed. If the filter and seal are
OK, check the Main Regulator Valve in the Oil Pump. Refer to the Service Information for the above
procedures.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Replace the Transmission Solenoid/TRS Assembly per the Service Information. (Refer to 21 - TRANS-
MISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE/TRANS SOLENOID/TRS ASSY -REMOVAL)
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
7.CHECK IF THE DTC SET IN PARK, NEUTRAL, OR REVERSE
With the scan tool, check the DTC EVENT DATA for P0846.
NOTE: Make sure to record all DTC EVENT DATA stored in the scan tool for future reference in this test
procedure.
Does the DTC EVENT DATA show the DTC P0846 set in Park, Neutral, or Reverse?
Ye s>>
Go To 12
No>>
Go To 8
8.CHECK IF THE 2C PRESSURE SWITCH READS CLOSED
With the scan tool, check the DTC EVENT DATA for P0846.
Does the DTC EVENT DATA show the 2C Pressure Switch reading CLOSED?
Ye s>>
Go To 10
No>>
Go To 9
9.CHECK THE LINE PRESSURE
In the DTC EVENT DATA recorded earlier,compare the Line Pressure and the Desired Line Pressure.
Is the Line Pressure less than 40 psi, and significantly below the Desired Line Pressure?
Ye s>>
Repair as necessary to correct low line pressure. Check fluid level and adjustasnecessary.Iffluidlevel
is OK, check the Primary Oil Filter seal for a split, crack, or improperly installed. If the filter and seal are
OK, check the Main Regulator Valve in the Oil Pump. Refer to the Service Information for the above
procedures.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Go To 15
10.CHECK THE PCM AND WIRING
Turn the ignition off to the lock position.
Remove the Ignition Switch Feed fuse from the TIPM.
CAUTION: Removal of the Ignition Switch Feed fuse from the TIPM will prevent the vehicle from being
startedingear.
WARNING: The Ignition Switch Feed fuse must be removed from the TIPM. Failure to do so can result in
personal injury or death.
Install the Transmission Simulator, Miller tool #8333.
Ignition on, engine not running.
With the Transmission Simulator, turn the Pressure Switch selector switchtothe2Cposition.
With the scan tool, monitor the 2C Pressure Switch while pressing the Pressure Switch test button on the Trans-
mission Simulator.
Did the state of the 2C Pressure Switch change while pressing the Pressure Switch Test button?
Ye s>>
Go To 11
No>>
Go To 12
15.CHECK IF THE #5 AND/OR #7 CHECK BALL IS CUT OR DAMAGED
Turn the Ignition off to the lock position.
Remove the Valve Body Assembly per the Service Information.
Inspect the #5 and #7 check balls for any cuts or damage.
Inspect the 2C accumulator piston and seals and also the 2C tower seal on topof the valve body. Refer to the
Service Information.
Where there any problems found?
Ye s>>
Repair as necessary. Check for excessive clutch debris in the transmission oil pan. If excessive clutch
debris is present, repair 2C clutch as necessary. Refer to the Service Information for proper repair pro-
cedures.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Go To 16
16.CHECK FOR EXCESSIVE FLUID LEAKAGE WITHIN THE 2C CLUTCH CIRCUIT
Air check the 2C Clutch hydraulic circuit. Refer to the Service Information.
NOTE: This hydraulic clutch circuit contains a small bleed orifice. Smallleakage is considered normal.
Was there excessive air leakage in the 2C Clutch hydraulic circuit?
Ye s>>
Repair as necessary. Refer to the Service Information.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1.
No>>
Replace the Transmission Solenoid/TRS Assembly per the Service Information. (Refer to 21 - TRANS-
MISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE/TRANS SOLENOID/TRS ASSY -REMOVAL)
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)