Jeep Liberty KJ. Manual — part 1160
•
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 current gear. For example, this code
would be set if the UD pressure switch remained off while the transmission was in second gear.
Possible Causes
RELATED RELAY DTC’S PRESENT
LOW FLUID LEVEL
NO. 2 CHECK BALL CUT OR DAMAGED
LOW LINE PRESSURE
CRACKED OR MISINSTALLED 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
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
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
REVERSE
OPEN
OPEN
OPEN
OPEN
OPEN
P/N
CLOSED**
OPEN
OPEN
OPEN
OPEN
1ST
CLOSED*
OPEN
OPEN
CLOSED
OPEN
2ND
OPEN
CLOSED
OPEN
CLOSED
OPEN
2ND PRIME
OPEN
OPEN
CLOSED
CLOSED
OPEN
3RD
OPEN
OPEN
OPEN
CLOSED
CLOSED
4TH
OPEN
OPEN
CLOSED
OPEN
CLOSED
5TH
OPEN
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 RELATED DTCS
With the scan tool, check for other transmission DTC’s.
Are there any Transmission Control Relay, Line Pressure, and/or Loss of Prime DTCs present?
Yes
>> Refer to the Transmission category and perform the appropriate symptom. If a Loss of Prime DTC is
present, perform its respective test first. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC -
45RFE/545RFE - DIAGNOSIS AND TESTING)
No
>> Go To 2
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AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS - (DIESEL)
KJ
2.
CHECK FOR PRESSURE SWITCH DTCS
Are there two or more other pressure switch rationality DTCs present in addition to P0876?
Yes
>> Go To 3
No
>> Go To 4
3.
CHECK IF ALL PRESSURE SWITCHES READ CLOSED
With the scan tool, read and record all 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 show all pressure switches reading CLOSED?
Yes
>> Refer to the symptom category and perform diagnostics for P0882. Diagnose the symptom as if the
DTC is current.
No
>> Go To 4
4.
CHECK FOR OTHER DTCS
With the scan tool, check for other transmission DTC’s.
Is the DTC P2704 present also?
Yes
>> 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)
No
>> Go To 5
5.
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 P0876?
Yes
>> Go To 6
No
>> Refer to the symptom list and perform diagnostics for the DTC listed in the DTC EVENT DATA.
Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)
6.
CHECK IF DTC EVENT DATA WAS SET IN PARK, NEUTRAL OR REVERSE
Refer to the DTC EVENT DATA recorded earlier.
Did the DTC P0876 set in Park, Neutral, or Reverse?
Yes
>> Go To 10
No
>> Go To 7
KJ
AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS - (DIESEL)
21 - 585
7.
CHECK FOR UD PRESSURE SWITCH STATUS
Refer to the DTC EVENT DATA recorded earlier.
Did the DTC P0876 set with the UD Pressure Switch closed?
Yes
>> Go To 10
No
>> Go To 8
8.
CHECK 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?
Yes
>> Repair as necessary to correct low line pressure. Check fluid level and adjust as necessary. If fluid level
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 9
9.
CHECK THE (T29) UD PRESSURE SWITCH SENSE CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT
Turn the ignition off to the lock position.
Disconnect the TCM harness connector.
Disconnect the Transmission Solenoid/TRS Assembly harness connec-
tor.
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?
Yes
>> 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
>> 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)
10.
CHECK THE TCM AND WIRING
Turn the ignition off to the lock position.
Remove the Starter Relay.
CAUTION: Removal of the Starter Relay will prevent the vehicle from being started in gear.
WARNING: The Starter Relay must be removed from the PDC. Failure to do so can result in personal injury
or death.
NOTE: Failure to remove the Starter Relay can cause a Transmission - No Response condition.
Install the Transmission Simulator, Miller tool #8333.
Ignition on, engine not running.
With the Transmission Simulator, turn the Pressure Switch selector switch to the UD position.
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AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS - (DIESEL)
KJ
With the scan tool, monitor the UD Pressure Switch state while pressing the Pressure Switch Test button on the
Transmission Simulator.
Did the state of the UD Pressure Switch change while pressing the Pressure Switch Test button?
Yes
>> Go To 14
No
>> Go To 11
11.
CHECK THE (T29) UD PRESSURE SWITCH SENSE CIRCUIT FOR AN OPEN
Turn the ignition off to the lock position.
Disconnect the Transmission Simulator, Miller tool #8333.
Disconnect the TCM harness connector.
Measure the resistance of the (T29) UD Pressure Switch Sense circuit
from the Transmission Solenoid/TRS Assembly harness connector and
the appropriate terminal of the TCM harness connector.
Is the resistance above 5.0 ohms?
Yes
>> Repair the (T29) UD Pressure Switch 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 12
12.
CHECK THE (T29) UD PRESSURE SWITCH SENSE CIRCUIT FOR A SHORT TO GROUND
Measure the resistance between ground and the (T29) UD Pressure
Switch Sense circuit.
Is the resistance below 5.0 ohms?
Yes
>> Repair the (T29) UD Pressure Switch 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 13
KJ
AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS - (DIESEL)
21 - 587
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