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
RELATED TCM POWER INPUT DTCS PRESENT
(T48) 4C PRESSURE SWITCH SENSE CIRCUIT OPEN
(F856) 5-VOLT SUPPLY CIRCUIT OPEN
(T48) 4C PRESSURE SWITCH SENSE CIRCUIT SHORT TO GROUND
(F856) 5-VOLT SUPPLY CIRCUIT SHORT TO GROUND
(T48) 4C PRESSURE SWITCH SENSE CIRCUIT SHORT TO OTHERS
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 DTC’s
Is there any Loss of Prime, TCM Power Input, and/or Line Pressure Sensor DTCspresent?
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
11 .CHECK PCM AND WIRING
Turn the ignition off to the lock position.
Remove the Line Pressure Adapter, Miller tool #8259 and 0-300 psi Test Gauge, Miller tool #C-3293-SP.
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.
On the Transmission Simulator, turn the Pressure Switch selector switch to4C.
Ignition on, engine not running.
With the scan tool, monitor the 4C Pressure Switch state while pressing andholding the Pressure Switch test button
and wiggling the wire harness and connectors that pertain to the 4C PressureSwitch.
Did the 4C Pressure Switch state change to closed and remain closed while wiggling the wires?
Ye s>>
Go To 12
No>>
Go To 14
12.CHECK FOR EXCESSIVE DEBRIS
Turn the ignition off to the lock position.
Remove the Transmission Simulator, Miller tool #8333.
Remove and inspect the Transmission Oil Pan per the Service Information.
Does the Transmission Oil Pan contain excessive debris or contamination?
Ye s>>
Repair the cause of the excessive debris in the Transmission Oil Pan. Referto the Service Information
for the proper procedures.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Go To 13
13.CHECK 4C HYDRAULIC CLUTCH CIRCUIT
Remove the Valve Body and air check the 4C hydraulic clutch circuit (in the case) for leakage per the Service
Information.
NOTE: The 4C hydraulic clutch circuit contains a small bleed orifice. A small amount of air leakage is nor-
mal.
Was there excessive air leakage noticed during the air check?
Ye s>>
Repair as necessary. Check the 4C clutch piston, piston seals and bleed orifice assembly.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Disassemble and inspect the Valve Body and repair as necessary. Inspect the 4C Accumulator piston
and seals. If no problems are found in the Valve Body, replace the Transmission Solenoid/TRS Assem-
bly per the Service Information.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
16.CHECK THE (T48) 4C 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 (T48) 4C 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 (T48) 4C Pres-
sure Switch Sense circuit and any other circuit(s) in the Trans-
mission Solenoid/TRS Assembly harness connector?
Ye s>>
Repair the (T48) 4C 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.CHECK 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 Pie 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.). IfthedatashowstheDTCsetwhiletheLine
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 .
2.DTC DATA SHOW CURRENT DTC
With the scan tool, check the DTC EVENT DATA.
Does the DTC EVENT DATA show data for DTC P0988?
Ye s>>
Go To 3
No>>
Refer to the Transmission category and perform the appropriate symptom identified in the DTC EVENT
DATA.
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 Sense DTCs present in additiontoP0988?
Ye s>>
Go To 4
No>>
Go To 7
4.RELATED DTC PRESENT
With the scan tool, check the DTC EVENT DATA for P0988.
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 P0988?
Ye s>>
Refer to Transmission category and perform diagnostics for the DTC P0882.
No>>
Go To 5
5.CHECK IF 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.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
7.CHECK IF THE DTC P0871 ALSO SET
With the scan tool, check Transmission DTCs.
Is the DTC P0871 also present?
Ye s>>
Refer to the Transmission category and perform the appropriate symptom.
No>>
Go To 8
8.CHECK IF THE DTC SET IN PARK, REVERSE OR NEUTRAL
With the scan tool, check the DTC EVENT DATA for P0988.
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 set in Park, Neutral, or Reverse for P0988?
Ye s>>
Go To 13
No>>
Go To 9
9.CHECK IF THE DTC EVENT DATA READS CLOSED
With the scan tool, check the DTC EVENT DATA for P0988.
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 4C Pressure Switch reading CLOSED?
Ye s>>
Go To 11
No>>
Go To 10
10.CHECK THE PRIMARY OIL FILTER SEAL
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
11 .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 switchtothe4Cposition.
14.CHECK THE (T48) 4C PRESSURE SWITCH SENSE CIRCUIT FOR A SHORT TO GROUND
Measure the resistance between ground and the (T48) 4C Pressure
Switch Sense circuit.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the (T48) 4C Pressure Switch Sense circuit for a
short to ground.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1.
No>>
Replace the Powertrain Control Module per the Service
Information. With the scan tool, perform the QUICK LEARN
procedure.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
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 4C accumulator piston and seals and also the 4C 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 4C 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 LEAKAGE WITHIN THE 4C CLUTCH CIRCUIT
Air check the 4C 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 4C Clutch hydraulic circuit?
Ye s>>
Repair as necessary. Refer to the Service Information.
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.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
P1736-GEAR RATIO ERROR IN 2ND PRIME
For a complete wiring diagramRefer to Section 8W.
When Monitored:
Continuously with the ignition on, engine running, with the transmissionin gear.
Set Condition:
If the ratio of the Input RPM to the Output RPM does not match the current gearratio. This DTC can take up
to five minutes of problem identification before illuminating the MIL
Possible Causes
RELATED DTC’S PRESENT
INPUT SPEED SENSOR OR WIRING
LOW FLUID LEVEL
CRACKED OR MIS-INSTALLED PRIMARY OIL FILTER OR SEAL
WORN SOLENOID SWITCH VALVE OR PLUGS
STUCK OR STICKING MAIN REGULATOR VALVE
BURNED UD OR 4C CLUTCH
CUT 4C OR UD PISTON SEAL
BROKEN 4C PISTON CASTING
BROKEN OR MISSING 4C BLEED ORIFICE
BROKEN OR MISSING UD BLEED ORIFICE
CUT 4C OR UD ACCUMULATOR PISTON SEAL
CRACKED 4C OR UD ACCUMULATOR PISTON
EXTRA CHECK BALL IN PASSAGE DOWNSTREAM OF #7 CHECK BALL POCKET
TRANSMISSION SOLENOID/TRS ASSEMBLY
BROKEN WELD - REACTION CARRIER TO REVERSE SUN GEAR
MISSING TEETH ON INPUT CLUTCH HUB TONE WHEEL
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 two speed sensors, one to measure input RPM and one to measure output RPM.
These inputs are essential for proper transmission operation. Therefore, the integrity of this data is verified through
the following checks:
1) When in gear, if the gear ratio does not compare to a known gear ratio, the corresponding in-gear trouble code
is set (DTCs P0731-36).
2) An excessive change in input or output speeds indicating signal intermittent which may result in the DTCs P0715
and/or P0720 to set.
3) If the common speed sensor ground circuit is lost, both sensor inputs will read the signal from the input speed
sensor at idle in neutral. Since the input speed sensor reads 60 teeth from the input clutch hub and the output
speed sensor reads 30 teeth from the park gear, the result is an apparent speed ratio of 1:2 and may cause the
DTC P1794 to set when at a stop.
Diagnostic Test
1.DETERMINING IF RELATED DTC’S ARE PRESENT
With the scan tool, check for other transmission DTCs.
Are any Transmission: solenoid, line pressure, speed sensor, or loss of primeDTCspresent?
Ye s>>
Refer to appropriate symptom in the Transmission category. Perform the test for P0944-LOSS OF
PRIME first if it is present.
No>>
Go To 2
2.CHECK DTC EVENT DATA
With the scan tool, read and record the DTC EVENT DATA.
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 display information for the DTC P1736?
Ye s>>
Go To 3
No>>
Go To 6
3.CHECK RPM IN DTC EVENT DATA
Refer to the DTC EVENT DATA recorded earlier.
Does the Input RPM read zero?
Ye s>>
Check the input speed sensor and wiring. Refer to test P0715 and diagnose asif the DTC is current.
No>>
Go To 4
4.CHECK LINE PRESSURE READING
Refer to the DTC EVENT DATA recorded earlier.
Isthelinepressurereadingmorethan10 psi below the desired line pressure?
Ye s>>
Go To 5
No>>
Go To 6
5.PLUGGED TRANSMISSION OIL FILTER
Turn the ignition off to the lock position.
Remove and inspect the Transmission Oil Pan for excessive debris per the Service Information.
Remove and inspect the Primary Oil Filter per the Service Information.
NOTE: Make sure the Primary Transmission Oil Filter and/or seal is not cracked or split.
Does the Oil Pan contain excessive debris and/or is the Primary Oil Filter cracked or plugged?
Ye s>>
Repair the plugged, cracked, or split Primary Transmission Oil Filter and/or seal. If the Primary Trans-
mission Oil Filter is plugged, refer to the Service Information for the proper hydraulic clutch repair pro-
cedure.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Remove the Transmission Oil Pump per the Service Information. Check the main Regulator Valve for
sticking in its bore, scoring, and/or damage and clean and repair as necessary. If no problem is found,
replace the Transmission Solenoid/TRS Assembly.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)