When Monitored:
Continuously while driving in a forward gear.
Set Condition:
The PCM continuously monitors Actual Line Pressure and compares it to DesiredLinePressure.IftheActual
Line Pressure is more than 10 psi below Desired Line Pressure, this DTC willset.
Possible Causes
CHECK FOR RELATED DTC’S
LOW FLUID LEVEL
(F856) 5-VOLT SUPPLY CIRCUIT OPEN
POOR LINE PRESSURE SENSOR CONNECTION
(F856) 5-VOLT SUPPLY CIRCUIT SHORT TO GROUND
(F856) 5-VOLT SUPPLY CIRCUIT SHORT TO VOLTAGE
(T118) PRESSURE CONTROL SOLENOID CONTROL CIRCUIT SHORT TO ANOTHER CIRCUIT
INTERNAL TRANSMISSION
LINE PRESSURE SENSOR
CRACKED, PLUGGED, OR MISINSTALLED PRIMARY OIL FILTER
STUCK OR STICKING MAIN REGULATOR VALVE
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
Line pressure is measured by the Line Pressure Sensor (LPS) and regulationis achieved by changing the duty
cycle of the Pressure Control Solenoid (PCS) controlled by the Transmission Control System. (5% duty cycle =
solenoid off = Max line pressure, 62%duty cycle = solenoid on = Min line pressure). The Transmission Control
System calculates the desired line pressure based on inputs from both the engine and transmission.
The Transmission Control System calculates torque input to the transmission and uses it as the primary input to the
desired line pressure calculation. This is called Torque Based Line Pressure. In addition, the line pressure is set to
a preset level 827 or 931kPa (120 or 135 psi) during shifts and in Park and Neutral to ensure consistent shift qual-
ity. The desired line pressure is continuously being compared to the actual line pressure. If the actual line pressure
is consistently lower than the target while driving, the line pressure lowDTC P0868 will set.
Diagnostic Test
1.CHECKFORRELATEDDTCS
With the scan tool, check for other transmission DTCs
Is the DTC P0932 present also?
Ye s>>
Refer to the Transmission category and perform the appropriate symptom.
No>>
Go To 2
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 DTC’S PRESENT
TRANSMISSION SOLENOID/TRS ASSEMBLY
EXCESSIVE DEBRIS IN OIL PAN
POOR LINE PRESSURE SENSOR CONNECTION
(T9) OD PRESSURE SWITCH SENSE CIRCUIT OPEN
TRANSMISSION CONTROL RELAY DTCS PRESENT
(T9) OD PRESSURE SWITCH SENSE CIRCUIT OPEN
(F856) 5-VOLT SUPPLY CIRCUIT OPEN
TRANSMISSION CONTROL RELAY OUTPUT CIRCUIT OPEN
(T9) OD PRESSURE SWITCH SENSE CIRCUIT SHORT TO GROUND
(F856) 5-VOLT SUPPLY CIRCUIT SHORT TO GROUND
(T9) OD PRESSURE SWITCH SENSE CIRCUIT SHORT TO OTHER CIRCUITS
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.CHECK IF RELATED DTCS ARE PRESENT
With the scan tool, check for other transmission DTCs.
Is there any Loss of Prime, Transmission Control Relay, 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 (T9) OD 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.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between the (T9) OD 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 (T9) OD Pressure
Switch Sense circuit and any other circuit(s) in the Transmis-
sion Solenoid/TRS Assembly harness connector?
Ye s>>
Repair the (T9) OD 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>>
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 P0870 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 and engine running.
Set Condition:
The appropriate DTC is set if one of the pressure switches are open or closedat the wrong time in a given
gear.
Possible Causes
RELATED TCM POWER INPUT DTCS PRESENT
LINE PRESSURE DTCS PRESENT
NO. 4 OR 6 CHECK BALL CUT OR DAMAGED
(T9) OD PRESSURE SWITCH SENSE CIRCUIT OPEN
(T9) OD PRESSURE SWITCH SENSE CIRCUIT SHORT TO GROUND
(T9) OD PRESSURE SWITCH SENSE CIRCUIT SHORT TO OTHER CIRCUITS
LOW LINE PRESSURE
WIRING AND CONNECTORS
CUT OD/REV PISTON SEAL
BROKEN OR MISSING DO/REV PISTON BLEED ORIFICE
BROKEN REACTION SHAFT SUPPORT SEAL RING
POOR MACHINING ON PUMP VALVE BODY FACE
BROKEN OR MISSING DRIBBLER ORIFICEASSEMBLY IN REACTION SHAFT SUPPORT
TRANSMISSION SOLENOID/TRS ASSEMBLY
CUT OD ACCUMULATOR PISTON SEAL
CRACKED OD ACCUMULATOR PISTON
BROKEN OR MISSING OD BLEED ORIFICE IN MAIN VALVE BODY
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.
6.CHECK IF 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 7
No>>
Go To 8
7.CHECK FOR LOW LINE PRESSURE
In the DTC EVENT DATA recorded earlier,compare the Line Pressure to 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 weal for a spit, crack , or improperly installed. If the filer 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.
8.CHECK IF IN PARK, NEUTRAL, OR REVERSE
Ignition on, engine not running.
With the scan tool, read and record the DTC EVENT DATA for P0871.
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 OD Pressure Switch DTC set while in Park, Neutral, or Reverse?
Ye s>>
Go To 18
No>>
Go To 9
9.CHECK IF THE OD PRESSURE SWITCH WAS OPEN
Refer to the DTC EVENT DATA recorded earlier for P0871.
Did the OD Pressure Switch read OPEN?
Ye s>>
Go To 10
No>>
Go To 15
10.CHECK FOR LOW LINE PRESSURE
Refer to the DTC EVENT DATA recorded earlier and 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 the fluid level. Check the Primary Oil Filter seal
for a split, crack, or improperly installed. Refer to the Service Information for the proper installation pro-
cedure. If the fluid level and filter are OK, check the Main Regulator Valvein the Oil Pump.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Go To 11
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 DTC’S PRESENT
TRANSMISSION SOLENOID/TRS ASSEMBLY
EXCESSIVE DEBRIS IN OIL PAN
POOR LINE PRESSURE SENSOR CONNECTION
(T29) UD PRESSURE SWITCH SENSE CIRCUIT OPEN
TRANSMISSION CONTROL RELAY DTCS PRESENT
(T29) UD PRESSURE SWITCH SENSE CIRCUIT OPEN
(F856) 5-VOLT SUPPLY CIRCUIT OPEN
(T29) UD PRESSURE SWITCH SENSE CIRCUIT SHORT TO GROUND
(F856) 5-VOLT SUPPLY CIRCUIT SHORT TO GROUND
(T29) UD PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
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.CHECK IF RELATED DTCS ARE PRESENT
With the scan tool, check for other transmission DTCs.
Is there any Loss of Prime, TCM Power Input Signal, 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 (T29) UD 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 (T29) UD 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 (T29) UD Pres-
sure Switch Sense circuit and any other circuit(s) in the Trans-
mission Solenoid/TRS Assembly harness connector?
Ye s>>
Repair the (T29) UD 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>>
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 P0875 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 and engine running.
Set Condition:
This DTC is set if the UD pressure switch is in the wrong state for the currentgear. For example, this code
would be set if the UD pressure switch remained off while the transmission was in second gear.
Possible Causes
RELATED TCM POWER INPUT DTCS PRESENT
LOW FLUID LEVEL
NO. 2 CHECK BALL CUT OR DAMAGED
LOW LINE PRESSURE
CRACKED OR MIS-INSTALLED SUMP FILTER OR SEAL
STICKING MAIN REGULATOR VALVE IN PUMP VALVE BODY
(T29) UD PRESSURE SWITCH SENSE CIRCUIT OPEN
(T29) UD PRESSURE SWITCH CIRCUIT SHORT TO GROUND
(T29) UD PRESSURE SWITCH SENSE CIRCUIT SHORT TO ANOTHER CIRCUITS
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 RELATED DTCS ARE PRESENT
With the scan tool, check for other transmission DTC’s.
Are there any TCM Power Input Signal, Line Pressure, and/or Loss of Prime DTCs present?
Ye s>>
Refer to the Transmission category and perform the appropriate symptom. If a Loss of Prime DTC is
present, perform its respective test first.
No>>
Go To 2