P1657

DTC P1657: Problem in Multiplex Line (SEFMJ) between TCM and Multiplex Control Unit
ULEV Model

NOTE: Record all freeze data and review General Troubleshooting Information before you troubleshoot.

1. Turn the ignition switch OFF.
2. Remove the under-dash fuse/relay box, and disconnect fuse/relay box connector E (13P).
3. Turn the ignition switch ON (II).





4. Measure the voltage between fuse/relay box connector terminal E10 and body ground.
Is there voltage?
YES- Check the gauge assembly. If the gauge assembly is OK, check for loose terminal fit in the multiplex control unit connectors. If necessary, substitute a known-good multiplex control unit, and recheck.
NO- Repair open or short in SEFMJ wire between TCM connector terminal A2 and the multiplex control unit (via fuse/relay box connector terminal E10).