Multi Module Handshake Failure
Table of contents
P1D20 JEEP Possible Causes
- Faulty Electronic Shifter Module (ESM) Internal Error
- Faulty Transmission Control Module (TCM) Internal Error
How do I fix code P1D20 JEEP?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Cost of diagnosing the P1D20 JEEP code
The cost of diagnosing the P1D20 JEEP code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
P1D20 JEEP Description
The purpose of the diagnostic is to monitor the question-answer CAN communication between the Electronic Shifter Module (ESM) and the Transmission Control Module (TCM) by comparing the ESM response to the expected value within the TCM software. The TCM sends two randomly generated values to the ESM and the ESM is expected to answer with a value calculated based upon these two random numbers. The TCM commands the ESM to reset if one of the following conditions occurs: No answer received within a calibrated amount of time, received answer is incorrect and is the same as the previous answer or the received answer is incorrect and is not the same as the previous answer.