Jeep Cherokee

 Service Manual

Power lock systems » Diagnosis and testing
Remote keyless entry transmitter

Before you proceed with this diagnosis, confirm proper power door lock switch operation. See Door Module in this group for the diagnostic procedures.

Remember, the Passenger Door Module (PDM) circuitry controls the output to each of the power lock motors. For circuit descriptions and diagrams, refer to 8W-61 - Power Door Locks in Group 8W - Wiring Diagrams.

Fig. 2 PDM Power Lock Switch Continuity

(1) Check each power lock motor for correct operation while moving the power lock switch to both the Lock and Unlock positions. If all of the power lock motors are inoperative, go to Step 2. If one power lock motor is inoperative, go to Step 3.

(2) If all of the power lock motors are inoperative, the problem may be caused by one shorted motor.

Unplugging a shorted power lock motor from the power lock circuit will allow the good power lock motor to operate. Unplug each power lock motor wire harness connector, one at a time, and recheck both the lock and unlock functions by operating the power lock switch. If all of the power lock motors are still inoperative after the above test, check for a short or open circuit between the power lock motors and the PDM. If unplugging one power lock motor causes the other motors to become functional, go to Step 3 to test the unplugged motor.

(3) Once it is determined which power lock motor is inoperative, that motor can be tested as follows.

Unplug the wire harness connector at the inoperative power lock motor. Apply 12 volts to the motor terminals to check its operation in one direction. Reverse the polarity to check the operation in the other direction.

If OK, repair the short or open circuits between the power lock motor and the PDM as required. If not OK, replace the faulty power lock motor.

REMOTE KEYLESS ENTRY TRANSMITTER

(1) Replace the Remote Keyless Entry (RKE) transmitter batteries. See Remote Keyless Entry Transmitter Battery Replacement in this group for the procedures. Test each of the transmitter functions.

If OK, discard the faulty batteries. If not OK, go to Step 2.

(2) Perform the Remote Keyless Entry Transmitter Programming procedure with the suspect transmitter and another known good transmitter. Use a DRB scan tool, as described in the proper Diagnostic Procedures manual.

(3) Test the RKE system operation with both transmitters. If both transmitters fail to operate the power lock system, see the diagnosis for the Remote Keyless Entry Receiver in this group. If the known good transmitter operates the power locks and the suspect transmitter does not, replace the faulty transmitter.

NOTE: Be certain to perform the Remote Keyless Entry Transmitter Programming procedure again following this test. This procedure will erase the access code of the test transmitter from the RKE receiver.

Power lock system and remote keyless entry system

Door module

Power lock motor

Remote keyless entry transmitter

Remote keyless entry receiver