Jeep Liberty KJ. Manual — part 1177
P1790-FAULT IMMEDIATELY AFTER SHIFT
For a complete wiring diagram Refer to Section 8W
•
When Monitored:
After a speed ratio error is stored.
•
Set Condition:
This DTC is set if the associated speed ratio DTC is stored within 1.3 seconds after a shift.
Possible Causes
FAULT AFTER SHIFT
Always perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting Procedure before proceeding. (Refer to
21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
Theory of Operation
This DTC will only be stored along with a gear ratio DTC. If this DTC is set, it indicates a probable hydraulic (line
pressure) or mechanical problem exists. Diagnosing the transmission should be based on the associated speed
ratio DTC and mechanical causes should be considered first.
INTENDED GEAR
CLUTCHES APPLYING
RECOMENDED DTC
REVERSE
UD** - MS
P0738
1ST
UD - LR*
P0731
2ND
UD - 2C
P0732
2ND PRIME
UD - 4C
P1736
3RD
UD - OD/MS
P0733
4TH
OD/MS - 2C
P0734
5TH
OD/MS - 2C
P0735
* L/R is used only up to 150 output RPM in 1st gear. ** UD will show as applied in Reverse but the UD clutch is
actually released. OD/MS is OD and/or MS.
Diagnostic Test
1.
INTENDED GEAR TO APPLIED CLUTCH
With the scan tool, check the DTC EVENT DATA to determine in which gear the slippage occurred and the clutches
that were applied.
With the DTC EVENT DATA, use the information provided above to determine the proper symptom for diagnosis.
View repair
Repair
Refer to the Transmission category and perform the appropriate symptom identified from the DTC
EVENT DATA, intended gear, and applied clutches.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
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AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS - (DIESEL)
KJ
P1793-TRD LINK COMMUNICATION ERROR
For a complete wiring diagram Refer to Section 8W.
KJ
AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS - (DIESEL)
21 - 653
•
When Monitored:
During torque managed shifts with Throttle angle above 54 degrees. This system is also tested whenever the
vehicle is stopped and the engine speed is below 1000 RPM.
•
Set Condition:
This code is set when the Transmission Control Module sends two subsequent Torque Reduction messages
(pulses the Torque Management Request Sense circuit to ground) to the Engine Control Module via the Torque
Management Request Sense circuit and the TCM does not receive a confirmation from the ECM over the
communication bus.
Possible Causes
RELATED DTC’S PRESENT
TORQUE MANAGEMENT REQUEST SENSE CIRCUIT OPEN
TORQUE MANAGEMENT REQUEST SENSE CIRCUIT SHORT TO GROUND
TORQUE MANAGEMENT REQUEST SENSE CIRCUIT SHORTED TO VOLTAGE
ENGINE CONTROL MODULE
TRANSMISSION 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
Engine Torque Management is used during heavy throttle, high-torque, high speed 1-2, 2-3, 4-2, and 3-1 shifts in
order to reduce the energy dissipation in the 2-4 and OD clutches to an acceptable level. The Engine Control Mod-
ule is expected to respond to a torque management test or request by transmitting a message over the communi-
cation bus to the Transmission Control Module.
Diagnostic Test
1.
CHECK FOR RELATED DTCS
With the scan tool, check for other transmission DTC’s
Are any of the DTCs P1694, P0731, P0732, P0733, P0734, and/or P1736 present also?
Yes
>> If any of these DTCs are present, disregard the P1793 DTC. 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)
No
>> Go To 2
2.
CHECK TO SEE IF DTC P1793 IS CURRENT
With the scan tool, Check the STARTS SINCE SET counter for P1793.
NOTE: NOTE: This counter only applies to the last DTC set.
Is the STARTS SINCE SET counter set at 2 or less?
Yes
>> Go To 3
No
>> Go To 7
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AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS - (DIESEL)
KJ
3.
TORQUE MANAGEMENT REQUEST SENSE CIRCUIT OPEN
Turn the ignition off to the lock position.
Disconnect the TCM harness connector.
Disconnect the ECM harness connector.
Measure the resistance of the Torque Management Request Sense cir-
cuit from the TCM harness connector to the ECM harness connector.
Is the resistance above 5.0 ohms?
Yes
>> Repair the Torque Management Request Sense circuit for
an open.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
No
>> Go To 4
4.
TORQUE MANAGEMENT REQUEST SENSE CIRCUIT SHORT TO GROUND
Measure the resistance between ground and the Torque Management
Request Sense circuit.
Is the resistance below 5.0 ohms?
Yes
>> Repair the Torque Management Request Sense circuit for a
short to ground.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION
TEST - VER 1. (Refer to 21 - TRANSMISSION/TRANS-
AXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PRO-
CEDURE)
No
>> Go To 5
KJ
AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS - (DIESEL)
21 - 655
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