P1642
DTC P1642: QBATT Battery Signal Circuit Low Input1. Reset the ECM with the HDS.
2. Turn the ignition switch ON (II).
3. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1642 or P1643 indicated?
YES - Go to step 4.
NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the motor control module and the ECM.
4. Turn the ignition switch OFF.
5. Remove the IPU cover, and disconnect motor control module connector C (31P).
6. Turn the ignition switch ON (II).
7. Measure voltage between ECM connector terminal D13 and body ground.
Is there about 5 V?
YES - Go to step 11.
NO - Go to step 8.
8. Turn the ignition switch OFF.
9. Disconnect ECM connector D(16P).
10. Check for continuity between ECM connector terminal D13 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM (D13) and the motor control module.
NO - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.
11. Turn the ignition switch OFF.
12. Disconnect ECM connector D (16P).
13. Check for continuity between ECM connector terminal D13 and motor control module connector terminal C16.
Is there continuity?
YES - Replace the battery module.
NO - Repair open in the wire between the ECM (D13) and the motor control module.