P0736-GEAR RATIO ERROR IN REVERSE
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
LOW FLUID LEVEL
CUT LR TOWER SEAL ON MAIN VALVE BODY
CUT LR CLUTCH PISTON SEALS
BROKEN OR MISSING LR CLUTCH BLEED ORIFICE (IN LR CLUTCH RETAINER)
CUT LR ACCUMULATOR PISTON SEAL IN MAIN VALVE BODY
CRACKED LR ACCUMULATOR PISTON IN MAIN VALVE BODY
CUT OD/REV PISTON SEALS
BROKEN OR MISSING OD/REV BLEED ORIFICE (IN OD/REV CLUTCH PISTON)
BROKEN REVERSE CARRIER HUB WELD
BROKEN REVERSE SUN GEAR WELD TO THE REACTION CARRIER
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) Once in a particular gear, if the gear ratio varies from the correct 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 may result in the DTCs P0715 and/or
P0720 being set.
3) If the common speed sensor ground circuit is lost, both sensor inputs will read the pulses from the input speed
sensor when at a stop in neutral. Since the input speed sensor reads 60 teethfrom 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.
Diagnostic Test
1.CHECKFORRELATEDDTCS
With the scan tool, check for other transmission DTC’s
Are there any Transmission; solenoid, line pressure, speed sensor, and/or loss of prime DTC’s present?
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 IF DTC IS CURRENT
With the scan tool, perform the Reverse Gear Clutch test. Follow the instructions on the scan tool.
Increase the throttle angle, TPS degree, to 30°, for no more than a few seconds.
CAUTION: Do not overheat the transmission.
NOTE: Make sure to record all DTC EVENT DATA stored in the scan tool for future reference in this test
procedure.
Did the clutch test pass, input speed remain at zero?
Ye s>>
Go To 3
No>>
Go To 4
3.CHECK DTC EVENT DATA
The conditions necessary to set this DTC are not currently present.
With the scan tool, check the DTC EVENT DATA to help identify the conditionsin which the DTC was set.
Does the DTC EVENT DATA show an input speed reading of zero?
Ye s>>
Go To 8
No>>
Go To 4
4.POSSIBLE INTERNAL TRANSMISSION CAUSES
Remove the Transmission Oil Pan and Valve Body and check the following per the Service Information:
Clutch or metal debris in the pan
LR clutch tower seal on the main valve body or cuts and the LR accumulator piston and seals.
Air check the Reverse and LR Hydraulic Clutch circuits (in the case) for excessive air leakage.
NOTE: Both Hydraulic Clutch circuitscontain a small bleed orifice , a small amount of air leakage is normal.
The Reverse hydraulic clutch circuit bleed orifice connects to the OD hydraulic clutch cavity. A small
amount of air leakage into the OD hydraulic clutch circuit is considered normal.
Were there any problems found?
Ye s>>
Repair as necessary. If clutch debris is present, remove the transmissionand inspect the Reverse and
LR clutches, and inspect the Transmission Oil Pump and Main Regulator Valve for damage or sticking
in its bore.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Go To 5
5.CLUTCH TEST FAILURE
Did the clutch test fail in reverse?
Ye s>>
Go To 6
No>>
Te s t c o m p l e t e .
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
6.CHECK FOR BROKEN REVERSE SUN GEAR WELD
Working through the windows in the bottom of the case, check for a broken Reverse Sun gear weld to the reaction
carrier as follows:
1) Hold the Transmission Output Shaft by holding the Transmission Manual Lever in the park position.
2) Rotate the Input Annulus gear and drive shell, (the drum that encloses the two rearmost carriers).
3) Check to see if the reaction carrier (the front-most carrier, whose outer shell is splined to the 2C clutch) is rotat-
ing faster than the drive shell is being turned.
Is the reaction carrier turning faster than the drive shell?
Ye s>>
Go To 7
No>>
Replace the reaction carrier 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 REVERSE CARRIER HUB
Remove the Transmission per the Service Information and inspect the weld on the reverse carrier hub.
Were there any problems found?
Ye s>>
Repair as necessary. Refer to the Service Information for proper repair procedures.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
No>>
Disassemble and inspect the input clutch assembly. Check the Reverse clutch reaction plate snap ring.
Check the OD and Reverse clutch seals, discs, and bleed orifice (in the OD/Reverse clutch piston).
Check the Reverse hub and shaft. Repair as necessary. Refer to the Service Information for proper
repair procedures.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
8.CHECK FOR INTERMITTENT OPERATION
Intermittent gear ratio DTCs can be set by problems in the Input and Output Speed Sensor circuits and/or Speed
Sensor Ground circuit.
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.
Check the Speed Sensor wiring and connectors for good connection, then performawiggletestusingtheTrans-
mission Simulator, Miller tool #8333.
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>>
Te s t c o m p l e t e .
P0740-TCC OUT OF RANGE
For a complete wiring diagramRefer to Section 8W
When Monitored:
During Electronically Modulated Converter Clutch (EMCC) Operation.
Set Condition:
Transmission must be in EMCC, with input speed greater than 1750 RPM. TCC-LR Solenoid achieves the
maximum duty cycle and can not pull engine speed within 60 RPM of input speed. Also when the transmission
is in FEMCC and the engine slips TCC less than 100 RPM for 10 seconds. This DTCcantakeuptofive
minutes of problem identification before illuminating the MIL.
Possible Causes
RELATED DTC P0750 PRESENT
L/R SOLENOID
TCC SWITCH VALVE STUCK
T C C R E G U L AT O R VA LV E S T U C K
INPUT SHAFT SEAL RING CUT
TORQUE CONVERTER AND/OR INTERNAL TRANSMISSION
Always perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting Procedure before proceeding. (Refer to
21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
Theory of Operation
When in 2nd, 2nd Prime, 3rd, 4th or 5th gear, the torque converter clutch (TCC) can be engaged when certain
conditions are met. The TCC piston is electronically modulated by increasing the duty cycle of the LR Solenoid until
the torque converter slip difference (difference between engine and transmission input speed) is within 60 RPM.
Then the LR solenoid is fully energized(FEMCC – 100% duty cycle). Torque converter slip is monitored in FEMCC
to ensure adequate clutch capacity.
Diagnostic Test
1.CHECKFORRELATEDDTCP0750
With the scan tool, read transmission DTCs.
Is the DTC P0750 present also?
Ye s>>
Refer to the Transmission category and perform the appropriate symptom.
No>>
Go To 2
2.CHECK IF DTC P0740 IS CURRENT
With the scan tool, Read and RECORD ALL Transmission DTC’s. After recording DTCs, erase DTCs.
Drive the vehicle until the transmission temperature is at least 43° C or 110° F and the engine temperature at least
49° C or 120° F.
Perform the following steps 3 times.
Drive the vehicle to the speed of at least 88 Kmh or 55 mph.
Allow 4th or 5th gear to engage for at least 10 seconds.
Close the throttle.
Tip back into the throttle until the TPS angle is between 25 and 29 degrees.
NOTE: If the throttle angle goes over 30 degrees, you must close the throttleandtryagain.
Did the TCC engage during any of the attempts, Engine speed approximately equal to input speed?
Ye s>>
Go To 3
No>>
Go To 4
3.CHECK WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time. Usingthe schematics as a guide, inspect the
wiring and connectors specific to this circuit. Wiggle the wires while checking for shorts and open circuits.
Using the schematics as a guide, inspect the wiring and connectors specifictothiscircuit.
Wiggle the wires while checking for shorts and open circuits.
With the scan tool, check the DTC EVENT DATA to help identify the conditionsin which the DTC was set.
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>>
Te s t C o m p l e t e .
4.CHECK THE LR SOLENOID
With the scan tool, check for other transmission DTC’s.
Are the DTCs P1775 and P0841 present also?
Ye s>>
Replace Transmission Solenoid/TRS Assembly per the Service Information. (Refer to 21 - TRANSMIS-
SION/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)
No>>
Go To 5
5.CHECK THE TORQUE CONVERTER AND/OR INTERNAL TRANSMISSION
Repair internal transmission as necessary.
Check for the following possible causes. Refer to the Service informationfor the proper repair procedures.
Inspect the Transmission Oil Pump and Valve Body.
If no problems are found, replace the Transmission Solenoid/TRS Assembly.
Check the Torque Converter Switch Valve and the Torque Converter Clutch Control Valve for sticking in the bore.
Check the Teflon seal rings on the input shaft. Note: If one of the seal ringsis , the loose piece will often lodge in
the TCC switch valve, causing it to stick in it bore.
View repair
Repair
In all cases, replace the Torque Converter. Make sure to check all other possible causes in addition to
the Torque Converter.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21- TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
When Monitored:
Initially at power-up, then every 10 seconds thereafter. The solenoid circuits will also be tested immediately
after a gear ratio or pressure switch error is detected.
Set Condition:
After three consecutive solenoid continuity test failures, or one failure if test is run in response to a gear ratio
or pressure switch error.Note: This DTC is strictly an electrical fault and does not apply to any internal
transmission failures.
Possible Causes
RELATED TIPM TCM DTCS PRESENT
(T20) LR SOLENOID CONTROL CIRCUIT SHORT TO OTHER CIRCUITS
(T20) LR SOLENOID CONTROL CIRCUIT OPEN
(T20) LR SOLENOID CONTROL CIRCUIT SHORT TO GROUND
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 Control System uses six electronically controlled solenoids that allow hydraulic fluid to be applied
to various friction elements (clutches), which enables the gear requested. The continuity of each solenoid circuit is
periodically tested. Each inactive solenoid is turned on for a few milliseconds, then off. Each active solenoid is
turned off for a few milliseconds, then on. This pulsing of voltage to the solenoid causes an inductive spike which
can be sensed by the Transmission Control System. If an inductive spike is not sensed by the Transmission Control
System during the continuity check, it is tested again. If the test fails three consecutive times, the appropriate Diag-
nostic Trouble Code (DTC) is set. If the solenoid test is run in response to agear ratio or pressure switch error, one
failure will result in setting the appropriate DTC.Note: This DTC is strictly an electrical fault and does not apply
to any internal transmission failures.
Diagnostic Test
1.CHECK FOR TIPM TCM DTCS
With the scan tool, check for other transmission DTCs.
Are there any TIPM TCM DTCs present?
Ye s>>
Refer to the Transmission category and perform the appropriate symptom.
No>>
Go To 2
2.CHECK TO SEE IF P0750 IS PRESENT
Ignition on, engine not running.
With the scan tool, erase all Transmission DTC’s.
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 scan tool, actuate the LR Solenoid.
When Monitored:
Initially at power-up, then every 10 seconds thereafter. The solenoid circuits will also be tested immediately
after a gear ratio or pressure switch error is detected.
Set Condition:
After three consecutive solenoid continuity test failures, or one failure if test is run in response to a gear ratio
or pressure switch error.Note: This DTC is strictly an electrical fault and does not apply to any internal
transmission failures.
Possible Causes
RELATED TIPM TCM DTCS PRESENT
(T219) 2C SOLENOID CONTROL CIRCUIT SHORT TO OTHER CIRCUITS
(T219) 2C SOLENOID CONTROL CIRCUIT OPEN
(T219) 2C SOLENOID CONTROL CIRCUIT SHORT TO GROUND
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 Control System uses six electronically controlled solenoids that allow hydraulic fluid to be applied
to various friction elements (clutches), which enables the gear requested. The continuity of each solenoid circuit is
periodically tested. Each inactive solenoid is turned on for a few milliseconds, then off. Each active solenoid is
turned off for a few milliseconds, then on. This pulsing of voltage to the solenoid causes an inductive spike which
can be sensed by the Transmission Control System. If an inductive spike is not sensed by the Transmission Control
System during the continuity check, it is tested again. If the test fails three consecutive times, the appropriate Diag-
nostic Trouble Code (DTC) is set. If the solenoid test is run in response to agear ratio or pressure switch error, one
failure will result in setting the appropriate DTC.Note: This DTC is strictly an electrical fault and does not apply
to any internal transmission failures.
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.
No>>
Go To 2
2.CHECK TO SEE IF P0755 IS PRESENT
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 scan tool, actuate the 2C Solenoid.
Did the 2C Solenoid LED blink on and off on the Transmission Simulator?
Ye s>>
Go To 3
No>>
Go To 4
When Monitored:
Initially at power-up, then every 10 seconds thereafter. The solenoid circuits will also be tested immediately
after a gear ratio or pressure switch error is detected.
Set Condition:
After three consecutive solenoid continuity test failures, or one failure if test is run in response to a gear ratio
or pressure switch error.Note: This DTC is strictly an electrical fault and does not apply to any internal
transmission failures.
Possible Causes
RELATED TIPM TCM DTCS PRESENT
(T60) OD SOLENOID CONTROL CIRCUIT SHORT TO OTHER CIRCUITS
(T60) OD SOLENOID CONTROL CIRCUIT OPEN
(T60) OD SOLENOID CONTROL CIRCUIT SHORT TO GROUND
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 Control System uses six electronically controlled solenoids that allow hydraulic fluid to be applied
to various friction elements (clutches), which enables the gear requested. The continuity of each solenoid circuit is
periodically tested. Each inactive solenoid is turned on for a few milliseconds, then off. Each active solenoid is
turned off for a few milliseconds, then on. This pulsing of voltage to the solenoid causes an inductive spike which
can be sensed by the Transmission Control System. If an inductive spike is not sensed by the Transmission Control
System during the continuity check, it is tested again. If the test fails three consecutive times, the appropriate Diag-
nostic Trouble Code (DTC) is set. If the solenoid test is run in response to agear ratio or pressure switch error, one
failure will result in setting the appropriate DTC.Note: This DTC is strictly an electrical fault and does not apply
to any internal transmission failures.
Diagnostic Test
1.RELATED TIPM TCM DTCS PRESENT
With the scan tool, check for TIPM DTCs.
Are there any TIPM TCM DTCs present?
Ye s>>
Refer to the Transmission category and perform the appropriate symptom.
No>>
Go To 2
2.CHECK TO SEE IF P0760 IS PRESENT
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 Transmission Simulator, Miller tool #8333.
Ignition on, engine not running.
With the scan tool, actuate the OD Solenoid.