TCM Serial Communication Problem
2017-2022 Kia Niro EV Electric
Description
The PCM has detected a serial communication problem with the Transmission Control Module. Data exchange between the PCM and TCM is interrupted or corrupted, preventing coordinated powertrain operation.
Symptoms
- Check Engine Light
- Transmission in limp mode
- Harsh shifting
- No upshifts or downshifts
- Cruise control inoperative
Common Causes
- Faulty TCM
- CAN bus wiring damage
- Corroded CAN bus connector
- TCM power or ground issue
- PCM CAN bus driver failure
Diagnostic Steps
- Check TCM power supply and ground connections
- Inspect CAN bus wiring between PCM and TCM
- Test CAN bus resistance (approximately 60 ohms between CAN-H and CAN-L)
- Attempt to communicate with TCM using scan tool
- Check for TCM-specific DTCs
Repair Notes
Repair CAN bus wiring or connectors; replace the TCM if it has failed internally.
Related Codes
Other Powertrain Codes
- P0070Ambient Air Temperature Sensor Circuit
- P0071Ambient Air Temperature Sensor Range/Performance
- P0072Ambient Air Temperature Sensor Circuit Low
- P0073Ambient Air Temperature Sensor Circuit High
- P0115Engine Coolant Temperature (ECT) Sensor 1 Circuit
- P0116ECT Sensor 1 Circuit Range/Performance
- P0117ECT Sensor 1 Circuit Low Input
- P0118ECT Sensor 1 Circuit High Input
- P0119ECT Sensor 1 Circuit Intermittent
- P0125Insufficient Coolant Temperature for Closed Loop Fuel Control
P1602 on Other Vehicles
Common Questions
What does code P1602 mean on a 2017-2022 Kia Niro EV?
P1602 stands for "TCM Serial Communication Problem". The PCM has detected a serial communication problem with the Transmission Control Module. Data exchange between the PCM and TCM is interrupted or corrupted, preventing coordinated powertrain operation.
What are the symptoms of P1602 on a Kia Niro EV?
Common symptoms of P1602 include: Check Engine Light, Transmission in limp mode, Harsh shifting, No upshifts or downshifts, Cruise control inoperative.
What causes P1602 on a 2017-2022 Kia Niro EV?
Common causes of P1602 include: Faulty TCM, CAN bus wiring damage, Corroded CAN bus connector, TCM power or ground issue, PCM CAN bus driver failure.