P1542
DTC P1542: Climate Control Unit Signal Circuit High Voltage1. 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 P1542 indicated?
YES - Go to step 4.
NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the climate control unit and the ECM.
4. Turn the ignition switch OFF.
5. Wait for 1 minute. If the radiator fan is running, wait for 1 minute after the radiator fan stops.
6. Disconnect the 22P connector from the climate control unit.
7. Disconnect ECM connector C (22P).
8. Check for continuity between ECM connector terminal C5 and climate control unit 22P connector terminal No. 1.
Is there continuity?
YES - 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.1
NO - Repair open in the wire between the ECM (C5) and the climate control unit.