Circuit Description
The right heater temperature sensor is a thermistor that controls signal voltage to the Instrument Panel Integration Module (IPM). The IPM supplies voltage on circuit 520. When the sensor is cold, the resistance is high and the IPM will sense a high signal voltage at terminal D3, connector C1. When the sensor warms, resistance is reduced and the signal voltage is pulled low through circuit 61. Signal voltage will vary from 5 V (open circuit) to 0 V (short circuit).
Conditions for Setting the DTC
| • | The ignition is ON. |
| • | Circuit open or short. |
Action Taken When the DTC Sets
| • | A default value of 128 counts and 24°C (75°F) will be used by the IPM. |
| • | The default value allows the system to operate. |
| • | If the air delivery is heater, defog or defrost the air mix two door will cycle between full hot and full cold. |
Conditions for Clearing the MIL/DTC
| • | Using aScan Tool . |
| • | A current DTC will clear when the diagnostic runs and does not fail. |
| • | IPM battery voltage is interrupted. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Perform the Body Control Module (BCM) Diagnostic System Check before continuing with the diagnosis of this DTC.
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Ensures that the DTC was not set in error.
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Determines whether the cause of the malfunction is the sensor or an open or short in a circuit.
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The Scan Tool checks for proper sensor operation. Clear all the DTCs after the repair procedure is complete.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Was the BCM diagnostic system check performed? | -- | Go to Step 2 | Go to Diagnostic System Check - Body Control System in Body Control Systems | |
2 |
Is the specified voltage measured? | 5 V | Go to Step 3 | Go to Step 4 |
Did DTC reset? | -- | Go to Step 4 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | |
Did the RH inside air temperature sensor voltage decrease? | -- | Go to Step 5 | Go to Step 6 | |
5 | Replace sensor. Refer to Heater Temperature Sensor Replacement in HVAC. Is the replacement complete? | -- | Go to Step 9 | -- |
6 | Inspect CKT 61 (YEL) for an open or short . Refer to Wiring Repairs in Wiring Systems. Was an open or short located? | -- | Go to Step 8 | Go to Step 7 |
7 |
Is the replacement complete? | -- | Go to Step 9 | -- |
8 | Repair open or short in CKT 61 (YEL), Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 9 | -- |
Is the A/C system operating normally? | -- | Go to Diagnostic System Check - Body Control System in Body Control Systems | -- |
