P1542
DTC P1542: HTRS Passenger Compartment Heater Standby Signal Circuit High Input1. Reset the ECM.
2. Turn the ignition switch ON (II).
Is DTC P1541 or P1542 indicated?
YES - Go to step 3.
NO - Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the heater control panel and at the ECM.
3. Turn the ignition switch OFF.
4. Disconnect the 22P connector from the heater control panel.
5. Turn the ignition switch ON (II).
6. Measure voltage between ECM connector terminal A23 and body ground.
Is there about 5 V?
YES - Go to step 10.
NO - Go to step 7.
7. Turn the ignition switch OFF.
8. Disconnect ECM connector A (32P).
9. Check for continuity between ECM connector terminal A23 and body ground.
Is there continuity?
YES - Repair short in the wire between the ECM (A23) and heater control panel.
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.
10. Turn the ignition switch OFF.
11. Disconnect ECM connector A (32P).
12. Check for continuity between ECM connector terminal A23 and heater control panel 22P connector terminal No.8.
Is there continuity?
YES - Replace the heater control panel.
NO - Repair open in the wire between the ECM (A23) and the heater control panel.