Circuit Description
This is the hardware Ignition 1, CKT 439, input to the body control module (BCM) from the ignition switch.
Conditions for Setting the DTC
All of the following conditions must be met.
| • | The Ignition 1 input is not active |
| • | The Ignition 3 is active for 20 seconds |
Action Taken When the DTC Sets
The BCM stores DTC B1374 in memory.
Conditions for Clearing the DTC
| • | The BCM goes to sleep. The controller reinitializes with the fault cleared. |
| • | All BCM history codes will clear after 100 ignition cycles (from OFF to ON) with no current codes active during the 100 ignition cycles. |
| • | Use the Scan Tool . |
Diagnostic Aids
| • | The BCM will not communicate with the Scan Tool if Ignition 1 input is not active. |
| • | If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while wiggling the wiring and connectors. This can often cause the malfunction to appear. |
Test Description
The numbers listed below refer to the numbers on the diagnostic table.
-
This step determines if CKT 439 is shorted to ground.
-
This step determines if the BCM is internally shorted.
-
This step determines if voltage is supplied from the battery to the fuse.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the BCM System Check? | -- | Go to Step 2 | |
2 |
Does the scan tool display ACTIVE? | -- | Go to Diagnostic Aids | Go to Step 3 |
3 | Inspect the A/C BFC fuse. Is the fuse open? | -- | Go to Step 4 | Go to Step 6 |
4 |
Does the test lamp illuminate? | -- | Go to Step 5 | Go to Diagnostic Aids |
5 |
Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 11 |
6 |
Does the test lamp illuminate for one of the circuits? | -- | Go to Step 7 | Go to Step 9 |
7 | Test the ignition 1 positive voltage circuit for an open. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 10 |
8 | Repair the short to ground in the ignition 1 positive voltage circuit. Did you complete the action? | -- | Go to Step 12 | -- |
9 | Repair the open in the ignition feed circuit to the A/C BFC fuse. Did you complete the action? | -- | Go to Step 12 | -- |
10 | Inspect for poor connections at the harness connector of the BCM. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 11 |
11 | Replace the BCM. Refer to Body Control Module Replacement in Body Control Systems. Is the repair complete? | -- | Go to Step 12 | -- |
12 | Use the Scan Tool in order to clear the DTCs. Is the action complete? | -- | -- |
