H and AUTO

DTC Troubleshooting: B2997 or Indicator H and AUTO

DTC B2997 or DTC indicator H and AUTO: A Short in the Heater Core Temperature Sensor Circuit

1. Clear the DTC with the HDS.

2. Turn the ignition switch to LOCK (0), and then turn to ON (II).

3. Do the self-diagnostic with the HDS Initial Inspection and Diagnostic Overview or climate control unit. Initial Inspection and Diagnostic Overview

4. Check for DTCs.

Is DTC B2997 or H and AUTO indicated?
YES - Go to step 5.

NO - Intermittent failure. Check for loose wires or poor connections on the heater core temperature sensor circuit.


5. Turn the ignition switch to LOCK (0).

6. Remove the heater core temperature sensor, Service and Repair and test it. Heater Core Temperature Sensor Test

Is the heater core temperature sensor OK?
YES - Go to step 7.

NO - Replace the heater core temperature sensor.


7. Disconnect climate control unit connector A (32P) and B (16P).

8. Check for continuity between body ground and the heater core temperature sensor 2P connector terminals No. 1 and No. 2 individually.

Is there continuity?
YES - Repair short to body ground in the wire(s) between the climate control unit and the heater core temperature sensor.

NO - Go to step 9.






9. Check for continuity between the heater core temperature sensor 2P connector terminals No. 1 and No. 2.

Is there continuity?
YES - Repair short in the wires between the climate control unit and the heater core temperature sensor.

NO - Substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit. Climate Control Unit Removal/Installation