For 1990-2009 cars
Body Control Module Components
Body Control System Schematics
Power Distribution Schematics

### Circuit Description

Circuit 341 is the ignition 3 input to the body control module (BCM) from the ignition switch. When the BCM senses that the ignition 3 input is open, DTC B1379 sets.

### Conditions for Setting the DTC

The ignition 3 input is inactive after the ignition 1 input has been active for 20 seconds.

### Condition for Running the DTC

• | The ignition switch is on.

• | At least 20 seconds has elapsed since the ignition switch was cycled on.

### Action Taken When the DTC Sets

• | The SERVICE VEHICLE SOON indicator illuminates.

• | The check gauges chime sounds.

### Conditions for Clearing the DTC

• | A current DTC B1379 will clear when the malfunction is no longer present and the ignition switch is cycled.

• | All BCM history codes will clear after 100 ignition cycles (from OFF to ON) with no current codes active during the 100 ignition cycles.

### Diagnostic Aids

If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while wiggling the wiring and connectors. This action may often cause the malfunction to appear.

### Test Description

The numbers listed below refer to the numbers on the diagnostic table.

1. This step determines if CKT 341 is shorted to ground.

2. This step determines if the BCM is internally shorted.

3. This step determines if the cruise control module is internally shorted.

4. This step determines if voltage is supplied from the battery to the fuse.

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform the Body Control System Diagnostic? | Go to Step 2 | Go to Diagnostic System Check - Body Control System
2 |

1. Install a Scan Tool.
2. Turn ON the ignition, leaving the engine OFF.
3. With the Scan Tool, observe the IGNITION 3 INPUT data parameter in the BCM data list.

Does the scan tool display ACTIVE?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3 | Inspect the CRUISE fuse. Is the fuse open? | Go to Step 4 | Go to Step 7
4 |

1. Connect a test lamp between the CRUISE fuse terminals at the right IP junction block.
2. Turn ON the ignition, leaving the engine OFF.

Does the test lamp illuminate?

Go to Step 5

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

5 |

1. Turn OFF the ignition.
2. Disconnect the BCM connector containing the ignition 3 positive voltage circuit.
3. Turn ON the ignition, leaving the engine OFF.

Does the test lamp still illuminate?

Go to Step 6

Go to Step 11

6 |

1. Turn OFF the ignition.
2. Disconnect the cruise control module connector.
3. Turn ON the ignition, leaving the engine OFF.

Does the test lamp still illuminate?

Go to Step 9

Go to Step 12

7 |

1. Remove the CRUISE fuse.
2. Turn ON the ignition, leaving the engine OFF.
3. Probe both fuse terminals for the ignition 3 positive voltage circuit at the right IP junction block with a test lamp connected to a good ground.

Does the test lamp illuminate for one of the circuits?

Go to Step 8

Go to Step 10

8 | Test the ignition 3 positive voltage circuit for 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 13
9 | Repair the short to ground in the ignition 3 positive voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the action? | Go to Step 15 | --
10 | Repair the open in the ignition feed circuit to the CRUISE fuse. Refer to Wiring Repairs in Wiring Systems. Did you complete the action? | Go to Step 15 | --
11 | Inspect for poor connections at the harness connector of the BCM. 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 cruise 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 14
13 | Replace the BCM. Refer to Body Control Module Replacement . Important: Perform the setup procedure for the body control module. Refer to Body Control Module (BCM) Programming/RPO Configuration . Did you complete the repair? | Go to Step 15 | --
14 | Replace the cruise control module. Refer to Cruise Control Module Replacement in Cruise Control. Did you complete the repair? | Go to Step 15 | --
15 |

1. Use the Scan Tool in order to clear the DTCs.
2. Operate the vehicle within the Condition for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK