Circuit Description
The instrument panel integration module (IPM) communicates with the HVAC control module through the HVAC control module data signal and HVAC control module clock signal. This communication link is only used by the IPM and the HVAC control module.
Conditions for Running the DTC
The ignition is turned ON.
Conditions for Setting the DTC
| • | There is a loss of communications between the IPM and the HVAC control module. |
| • | The above conditions are present for 3 seconds. |
Action Taken When the DTC Sets
The HVAC system will be disabled.
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. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views | ||||
1 | Did you perform the HVAC Diagnostic System Check? | -- | Go to Step 2 | |
Turn ON the ignition, with the engine OFF. Is the HVAC control module inoperative? | -- | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | |
3 |
Does the test lamp illuminate? | -- | Go to Step 4 | Go to Step 7 |
4 | Connect a test lamp between the ignition 3 voltage circuit and the ground circuit of the HVAC control module. Does the test lamp illuminate? | -- | Go to Step 5 | Go to Step 8 |
5 | Measure the voltage between the HVAC control module data signal circuit of the HVAC control module and a good ground. Does the voltage measure near the specified value? | 1 V | Go to Step 6 | Go to Step 9 |
6 | Measure the frequency between the HVAC control module clock signal circuit of the HVAC control module and a good ground. Does the frequency measure near the specified value? | 930 Hz | Go to Step 11 | Go to Step 10 |
7 | Test the ignition 3 voltage circuit of the HVAC control module for a short to ground, 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 15 | -- |
8 | Test the ground circuit of the HVAC control module 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 15 | -- |
9 | Test the HVAC control module data signal circuit for a short to voltage, a short to ground, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
10 | Test the HVAC control module clock signal circuit for a short to voltage, a short to ground, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
11 | Inspect for poor connections at the harness connector of the HVAC control 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 15 | Go to Step 13 |
12 | Inspect for poor connections at the harness connector of the instrument panel integration module (IPM). 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 15 | Go to Step 14 |
13 | Replace the HVAC control module. Refer to HVAC Control Module Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- |
14 |
Important : Perform the Recalibration procedure for the instrument panel integration module. Replace the instrument panel integration module. Refer to Instrument Panel Module Replacement in Body Control System. Did you complete the replacement? | -- | Go to Step 15 | -- |
15 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
