Jeep Grand Cherokee WK. Manual — part 1439

P1631-TCM INTERNAL- PROCESSOR CLOCK PERFORMANCE

21 - 566

AUTOMATIC TRANSMISSION NAG1 - ELECTRICAL DIAGNOSTICS

WK

P1631-TCM INTERNAL- PROCESSOR CLOCK PERFORMANCE (CONTINUED)

For the Transmission circuit diagram (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - SCHE-
MATICS AND DIAGRAMS)

For a complete wiring diagram Refer to Section 8W

Theory of Operation

The Transmission Control Module (TCM) performs various internal tests to verify proper controller operation. This
DTC indicates that there is an issue with the TCM’s internal clock. If the TCM detects an error with the controllers
internal clock, the controller will enter Limp-in mode and illuminate the MIL.

•

When Monitored:
Continuously with the ignition on.

•

Set Condition:
If the TCM detects an error with the controllers internal clock.

Possible Causes

TRANSMISSION CONTROL MODULE

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)

Diagnostic Test

1.

TRANSMISSION CONTROL MODULE

View repair

Repair

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. Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/TRANSMISSION CONTROL MODULE for the appropriate service procedures.

Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.

WK

AUTOMATIC TRANSMISSION NAG1 - ELECTRICAL DIAGNOSTICS

21 - 567

P1632-TCM INTERNAL - TEST INTERNAL WATCHDOG PERFORMANCE

21 - 568

AUTOMATIC TRANSMISSION NAG1 - ELECTRICAL DIAGNOSTICS

WK

P1632-TCM INTERNAL - TEST INTERNAL WATCHDOG PERFORMANCE (CONTINUED)

For the Transmission circuit diagram (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - NAG1 - SCHE-
MATICS AND DIAGRAMS)

For a complete wiring diagram Refer to Section 8W

Theory of Operation

The Transmission Control Module (TCM) performs various internal tests to verify proper controller operation. This
DTC indicates that there is an issue with the TCM’s internal watchdog failed. If the TCM detects an error with the
controllers internal watchdog, the controller will enter Limp-in mode and illuminate the MIL.

•

When Monitored:
Continuously with the ignition on.

•

Set Condition:
If the TCM detects an error with the controllers internal watchdog.

Possible Causes

TRANSMISSION CONTROL MODULE

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - NAG1 - STANDARD PROCEDURE)

Diagnostic Test

1.

TRANSMISSION CONTROL MODULE

View repair

Repair

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. Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/TRANSMISSION CONTROL MODULE for the appropriate service procedures.

Perform NAG1 TRANSMISSION VERIFICATION TEST - VER 1.

WK

AUTOMATIC TRANSMISSION NAG1 - ELECTRICAL DIAGNOSTICS

21 - 569