Jeep Liberty KJ. Manual - part 1156

•

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 closed at 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 ORIFICE ASSEMBLY 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

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

REVERSE

OPEN

P/N

CLOSED**

OPEN

1ST

CLOSED*

OPEN

CLOSED

OPEN

2ND

OPEN

CLOSED

OPEN

CLOSED

OPEN

2ND PRIME

OPEN

CLOSED

OPEN

3RD

OPEN

CLOSED

4TH

OPEN

CLOSED

OPEN

CLOSED

5TH

OPEN

CLOSED

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.

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AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS - (DIESEL)

Diagnostic Test

DETERMINE IF RELATED TCM POWER INPUT DTCS ARE PRESENT

With the scan tool, check for other transmission DTCs.

Are there any TCM Power Input DTCs present also?

Yes

>> Refer to the Transmission category and perform the appropriate symptom.

>> Go To 2

CHECK FOR LINE PRESSURE DTCS

With the scan tool, read Transmission DTCs.

Are there any Line Pressure DTCs present?

Yes

>> Refer to the Transmission category and perform the appropriate symptom.

>> Go To 3

CHECK FOR OTHER PRESSURE SWITCH DTCS

With the scan tool, check Transmission DTCs.

Are there two or more other pressure switch rationality DTCs present in addition to P0871?

Yes

>> Go To 5

>> Go To 4

CHECK IF DTC IS CURRENT

With the scan tool, check 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 show data for P0871?

Yes

>> Go To 8

>> Refer to the Transmission category and perform the appropriate symptom. (Refer to 21 - TRANSMIS-

SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - DIAGNOSIS AND TESTING)

CHECK IF PRESSURE SWITCHES READ CLOSED

With the scan tool, check 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.

Do all the pressure switches read CLOSED in the DTC EVENT DATA?

Yes

>> Refer to the Transmission category and perform diagnostics for P0882. Follow instructions as if the DTC

is current. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - DIAGNOSIS
AND TESTING)

>> Go To 6

AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS - (DIESEL)

21 - 569

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?

Yes

>> Go To 7

>> Go To 8

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?

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 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.

>> 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)

CHECK IF IN DTC SET 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?

Yes

>> Go To 18

>> Go To 9

CHECK IF THE OD PRESSURE SWITCH IS OPEN

Refer to the DTC EVENT DATA recorded earlier for P0871.

Did the OD Pressure Switch read OPEN?

Yes

>> Go To 10

>> 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?

Yes

>> 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 Valve in the Oil Pump.

Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)

>> Go To 11

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AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS - (DIESEL)

11.

CHECK THE (T9) OD 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.

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?

Yes

>> 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)

>> Go To 12

12.

CHECK IF DTC RESETS

Reconnect all previously disconnected connectors.

With the scan too, erase transmission DTCs.

Test drive the vehicle, use the DTC EVENT DATA recorded earlier to help duplicate the conditions when the DTC
originality set.

Does the DTC P0871 reset?

Yes

>> Go To 13

>> Go To 22

13.

CHECK THE TRANSMISSION CONTROL MODULE

Remove the Transmission Control Relay.

Operate the vehicle in Drive.

Is the transmission slipping while in Drive?

Yes

>> Go To 14

>> Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion,

damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems
are found, replace the TCM 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)

14.

CHECK INTERNAL TRANSMISSION

Perform an Air Check Transmission Clutch Operation procedure per the Service Information.

AUTOMATIC TRANSMISSION 545RFE - ELECTRICAL DIAGNOSTICS - (DIESEL)

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