Rear Blend Pot Circuit Open (Active)

When Monitored:

With ignition on.

Set Condition:

This DTC will set if the A/C-Heater Control Module sees voltage more than 4.88 volts on the Rear Temperature Sensor Signal circuit.

Possible Causes:

5-Volt Supply circuit/Rear Temperature Sensor Signal circuit shorted high.
Rear A/C-Heater Control Module.
Rear Temperature Sensor Signal circuit open.
Sensor Return circuit open.
A/C-Heater Control Module.

CAUTION: Always turn ignition off before disconnecting or connecting any control module connector. Failure to do so could result in damage to control module.

NOTE: Ensure vehicle being tested has a fully charged battery. If it does not, false DTCs or error messages may occur.

NOTE: For component location, see appropriate illustration under COMPONENT LOCATIONS . For terminal identification, see appropriate illustration under CONNECTOR IDENTIFICATION . For circuit and wire color identification, see WIRING DIAGRAMS . For component removal and installation procedures, see appropriate component under REMOVAL & INSTALLATION .

Testing:

Turn ignition off. Connect DRBIII(R) to DLC. Disconnect the A/C-Heater Control Module C2 harness connector. Turn ignition on. Measure voltage between A/C-Heater Control Module C2 harness connector terminal No. 9 and ground. Measure voltage between A/C-Heater Control Module C2 harness connector terminal No. 12 and ground. Is voltage more than 5.5 volts on either circuit? If yes, repair appropriate circuit(s) for a short to voltage. Perform BODY VERIFICATION TEST under VERIFICATION TESTS. If no, go to next step.
Turn ignition off. Using the DRBIII(R), select INPUTS/OUTPUTS, then read REAR BLEND DOOR state. Connect a jumper wire between A/C-Heater Control Module C2 harness connector terminal No. 9 and ground. Does the state change from FULL HOT (not grounded) to FULL COLD (grounded). If yes, replace A/C-Heater Control Module. Perform BODY VERIFICATION TEST under VERIFICATION TESTS. If no, go to next step.
Disconnect Rear A/C-Heater Control Module C2 harness connector. Measure resistance between A/C-Heater Control Module C2 harness connector terminal No. 9 and Rear A/C-Heater Control Module terminal No. 8. Is resistance less than 5 ohms? If yes, go to next step. If no, repair open in Rear Temperature Sensor Signal circuit. Perform BODY VERIFICATION TEST under VERIFICATION TESTS.
Measure resistance between A/C-Heater Control Module C2 harness connector terminal No. 11 and Rear A/C-Heater Control Module terminal No. 6. Is resistance less than 5 ohms? If yes, go to next step. If no, repair open in Sensor Return circuit. Perform BODY VERIFICATION TEST under VERIFICATION TESTS.
Reconnect Rear A/C-Heater Control Module harness connector. Turn the Rear Blend Switch to full hot. Measure the resistance between A/C-Heater Control Module C2 harness connector terminals No. 9 and 12. The resistance should be approximately 2500 ohms. Slowly rotate the Rear Blend Switch from full hot to full cold while monitoring resistance. Resistance should change fluidly from approximately 2500 ohms to 12,000 ohms. Turn the Rear Blend Switch to full hot. Measure the resistance between A/C-Heater Control Module C2 harness connector terminals No. 9 and 12. The resistance should be approximately 10,000 ohms. Slowly rotate the Rear Blend Switch from full hot to full cold while monitoring resistance. The resistance should stay steady at approximately 10,000 ohms. Turn the Rear Blend Switch to full hot. Measure the resistance between A/C-Heater Control Module terminals No. 9 and 11. The resistance should be approximately 11,000 ohms. Slowly rotate the Rear Blend Switch from full hot to full cold while monitoring resistance. Resistance should change fluidly from approximately 12,000 ohms to 2500 ohms. Are all of the resistance measurements as specified? If yes, replace the A/C-Heater Control Module. Perform BODY VERIFICATION TEST under VERIFICATION TESTS. If no, replace the Rear A/C-Heater Control module. Perform BODY VERIFICATION TEST under VERIFICATION TESTS.