Turn ignition on. Using scan tool, clear DTCs. Cycle ignition key on and off several times. Using scan tool, read DTCs. If DTC P1698: NO BUS MESSAGE FROM TRANS CONTROL MODULE resets, go to next step. If DTC P1698: NO BUS MESSAGE FROM TRANS CONTROL MODULE does not reset, go to step 3 .
Turn ignition on. Using scan tool, attempt to communicate with TCM. If scan tool communicates with TCM, replace PCM. If scan tool does not communicate with TCM, perform NO RESPONSE FROM TRANSMISSION CONTROL MODULE test. See COMMUNICATIONS under SYSTEM TESTS in BODY CONTROL MODULES - CHEROKEE article in ACCESSORIES & EQUIPMENT.
At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

Fig 1: Identifying Transmission Control Module Connector Terminals

Courtesy of DAIMLERCHRYSLER CORPORATION

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

DTC P1698: No Bus Message From Trans Control Module: Testing