Circuit Description
The instrument panel integration module (IPM) communicates with the HVAC control module through the HVAC control module assembly data signal and HVAC control module clock signal. This communication link is only used by the IPM and the HVAC control module.
DTC Descriptor
This diagnostic procedure supports the following DTC:
B1000 Electronic Control Unit (ECU) Performance
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 Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 | Observe the display of the HVAC control module. Is the display of the HVAC control module blank? | -- | Go to Step 4 | Go to Step 3 |
Observe the display of the HVAC control module. Does the HVAC control module display only - - - - - ? | -- | Go to Step 6 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | |
4 |
Does the test lamp illuminate? | -- | Go to Step 5 | Go to Step 8 |
5 | 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 13 | Go to Step 9 |
6 |
Does the voltage measure near the specified value? | 1 V | Go to Step 7 | Go to Step 10 |
7 | 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 13 | Go to Step 12 |
8 | 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 17 | -- |
9 | 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 17 | -- |
10 | Test the HVAC control module data signal circuit for a short to voltage 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 HVAC control module data signal circuit 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 12 |
12 | 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 17 | Go to Step 14 |
13 | 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 17 | Go to Step 15 |
14 | Inspect for poor connections at the harness connector of the instrument panel 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 17 | Go to Step 16 |
15 | Replace the HVAC control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 17 | -- |
16 | Replace the IPM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 17 | -- |
17 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
