P1649

DTC P1637 (64, 71, 75): MCM Internal Circuit Malfunction
Update the MCM if it does not have the latest software, or substitute a known-good MCM, then recheck. If the symptom/indication goes away with a known-good MCM, replace the original MCM.

DTC P1638 (76): MCM Internal Circuit Malfunction
Update the MCM if it does not have the latest software, or substitute a known-good MCM, then recheck. If the symptom/indication goes away with a known-good MCM, replace the original MCM.

DTC P1649 (13, 14): ABS Operation Signal Circuit Problem

NOTE: If the ABS indicator light comes ON at the same time as IMA indicator light, troubleshoot the ABS system first.

1. Reset the MCM.
2. Turn the ignition switch ON (II).
Is DTC P1649 indicated?
YES - Go to step 3.
NO - intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the ABS control unit and at the MCM.
3. Turn the ignition switch OFF.
4. Turn the battery module switch OFF.
5. Remove the IPU lid.
6. Disconnect MCM connector A (31P).
7. Disconnect the ABS control unit 25P connector.





8. Check for continuity between MCM connector terminal A27 and body ground.
Is there continuity?
YES - Repair short in the wire between the ABS control unit and the MCM (A27).
NO - Go to step 9.





9. Connect ABS control unit 25P connector terminal No. 17 to body ground with a jumper wire.





10. Check for continuity between MCM connector terminal A27 and body ground.
Is there continuity?
YES - Update the MCM if it does not have the latest software, or substitute a known-good MCM and ABS control unit, then recheck. If the symptom/indication goes away with a known good MCM and ABS control unit, replace the original MCM and ABS control unit.
NO - Repair open in the wire terminal the ABS control unit (terminal 17) and the MCM (A27).