Circuit Description
The instrument panel integration module (IPM) commands left air temperature actuator movement with one of three voltage signals applied to the left air temperature door control circuit. A low voltage of 0 volts moves the left air temperature door toward full cold. A voltage of 2.5 volts stops the actuator. A voltage of 5 volts moves the left air temperature door toward full hot. The IPM determines the current position of the actuator by monitoring the feedback voltage of the air temperature door position signal circuit. The feedback potentiometer position is a function of the actuator position. A high voltage indicates a full hot left air temperature door position. A low voltage indicates a full cold left air temperature door position. The IPM controls the left air temperature door position in order to maintain the selected air temperature on the HVAC control module.
The IPM will perform a continuous test on the current feedback voltage. If the feedback voltage does not equal or fall within the calibrated limits, the DTC will set.
Conditions for Running the DTC
The ignition is turned ON.
Conditions for Setting the DTC
The IPM detects the signal circuit is less than 0.05 volt (3 counts) or greater than 4.90 volts (250 counts).
Action Taken When the DTC Sets
| • | A default value of 2.50 volts (128 counts) will be substituted for the left air temperature door position data by the IPM. |
| • | The IPM will toggle the actuator between full hot and full cool in an attempt to maintain the selected air temperature on the HVAC control module. |
Conditions for Clearing the DTC
| • | The DTC will become history if the IPM no longer detects a failure. |
| • | The history DTC will clear after 50 fault-free ignition cycles. |
| • | Use the scan tool in order to clear the DTCs. |
Diagnostic Aids
| • | If the condition is not present, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
| • | A damaged or broken air temperature door and or actuator can cause this DTC to set by allowing the actuator shaft to rotate unrestricted to its internal stop, creating an overtravel condition. The internal stops are outside of the feedback potentiometers 0-250 count working range. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Tests for the proper operation of the circuit in the high voltage range.
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Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.
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Tests for a short to ground in the 5 volt reference circuit.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: HVAC Schematics | ||||
1 | Did you perform the HVAC Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Does the scan tool indicate that the Left Temp Dr Actual parameter is within the specified range? | 0.05-4.90 V | Go to Diagnostic Aids | Go to Step 3 |
3 |
Does the scan tool indicate that the Left Temp Dr Actual parameter changes when the Left Temp Dr is commanded from Hot to Cold? | -- | Go to Step 12 | Go to Step 4 |
Does the scan tool indicate that the Left Temp Dr Actual parameter is greater than the specified value? | 4.90 V | Go to Step 5 | Go to Step 9 | |
Does the scan tool indicate that the Left Temp Dr Actual parameter is less than the specified value? | 0.05 V | Go to Step 6 | Go to Step 10 | |
Does the scan tool indicate that the Left Temp Dr Actual parameter is greater than the specified value? | 4.90 V | Go to Step 8 | Go to Step 7 | |
7 | Test the 5 volt reference circuit of the left air temperature actuator for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 14 |
8 | Test the 5 volt reference circuit of the left air temperature actuator for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 13 |
9 | Test the left air temperature door position signal circuit of the left air temperature actuator for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 14 |
10 | Test the left air temperature door position signal circuit of the left air temperature actuator for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 11 |
11 | Test the low reference circuit of the left air temperature actuator for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 14 |
12 | Inspect the left air temperature door for a condition allowing excessive travel of the actuator. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 13 |
13 | Inspect for poor connections at the harness connector of the left air temperature actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 15 |
14 | Inspect for poor connections at the harness connector of the instrument panel integration module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 16 |
15 |
Important: : Perform the Recalibration procedure for the left air temperature actuator. Replace the left air temperature actuator. Refer to Air Temperature Actuator Replacement - Left Side . Did you complete the replacement? | -- | Go to Step 17 | -- |
16 |
Important: : Perform the Recalibration procedure for the IPM. Replace the IPM. Refer to Instrument Panel Module Replacement in Body Control System. Did you complete the replacement? | -- | Go to Step 17 | -- |
17 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
