1988 JEEP CHEROKEE Service Repair Manual

Fig. 113: Test 7A - Location of Engine Control Connector (Cherokee)
Fig. 114: Test 8B - TCU 32-Way Connector (Cavity 10, Cherokee)
TEST 9A - WRONG TCU
NOTE: Perform TEST 1A - VERIFICATION OF THE COMPLAINT
before proceeding.
NOTE: The AW-4 is used only on 4.0L. In earlier years, it was

used with 2.5.L
The DRB-II has determined that the wrong Transmission Control
Unit (TCU) has been installed in the vehicle. There are two
transmission control units available for the Jeep AW4 transmission.
One is for the 4-cylinder 2.5L engine and the other is for the 6-
cylinder 4.0L engine.
1) using the DRB-II, read MODULE INFO. See HELP 1 for
assistance.
2) Determine what vehicle should be in the vehicle.
* 2.5L Engine: TCU 02 (Used in earlier years only)
* 4.0L Engine: TCU 01 (1993-94)
3) If the wrong transmission control unit is installed, the
vehicle shift points will be slightly different (the 2.5L engine TCU
has higher shift points).
TEST 10A - TESTING FOR INTERMITTENT SPEED SENSOR
NOTE: Perform TEST 1A - VERIFICATION OF THE COMPLAINT
before proceeding.
Fig. 115: Test 10A - Flow Chart (1 of 2)
Fig. 116: Test 10A - Schematic (Cherokee)

Fig. 117: Test 10A - Location of Transmission Connectors
Fig. 118: Test 10A - View of 7-Way Connector (Cherokee)
NOTE: See Fig. 115 for wiring diagram.

Fig. 119: Test 10A - Flow Chart (2 of 2)

Fig. 120: Test 10A - Schematic (Cherokee)
Fig. 121: Test 10A - TCU 32-Way Connector (Cavity 3)

Fig. 122: Test 10A - Location of Speed Sensor Connector
Fig. 123: Test 10A - Testing Speed Sensor (Cherokee)
WIRING DIAGRAMS

Fig. 124: Transmission Wiring Diagram (Cherokee)

Fig. 125: TCM Connector Terminals I.D., Circuits & Functions
Courtesy of Chrysler Corp.
REMOVAL & INSTALLATION
BRAKE SWITCH
Removal
Remove lower steering column cover or trim panels for access
to brake switch (if necessary). Disconnect brake switch electrical
connector. Thread brake switch from retainer and remove.