For 1990-2009 cars
Body Control Module Components
Cell 51: Ign Switch and Left Front Door Ajar Switch

### Circuit Description

This is a trouble code (both current and history) that indicates the DRL relay control output is shorted to battery.

### Conditions for Running the DTC

Meet all of the following conditions:

• | The ignition switch is in the RUN position.

• | The transaxle range switch is not in the PARK position.

• | The DRL option is configured.

• | The DRL relay output is active.

• | The DRL feedback is not present for 5 seconds.

### Action Taken When the DTC Sets

• | Turns OFF the DRL relay

• | Enters a fault state

• | Stores DTC B2603 in the BCM memory

• | The SERVICE VEHICLE SOON indicator will illuminate.

### Conditions for Clearing the DTC

• | The fault state is exited upon the program return to the DRL OFF state.

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

• | Use the Scan Tool .

### Diagnostic Aids

• | When the diagnostics direct you to take electrical measurements at the junction blocks, refer to Power Distribution Schematics in Wiring Systems for the terminal assignments of the junction blocks.

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

### Test Description

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

1. This step determines if the DRL relay is operating properly.

2. This step determines if there is a short to the battery in CKT 592 within the underhood junction block.

3. This step determines if there is a short to the battery in CKT 592 between the underhood wiring harness junction block and the body control module (BCM).

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the BCM system check performed? | -- | Go to Step 2 | Go to Body Control Module System Check
2 |

1. Replace the DRL relay with a known good relay on the underhood junction block.
2. Use the Scan Tool in order to enable the DRL relay.

Did the DRL relay activate?

--

Go to Step 8

Go to Step 3

3 |

1. Remove the DRL relay on the underhood junction block.
2. Back out the underhood junction block connector C3 terminal B12 CKT 592.
3. Use the J 39200 DMM in order to measure the voltage in CKT 592 between the underhood junction block connector C3 terminal B12 and ground.

Does the measured voltage equal the specified value?

0 V

Go to Step 5

Go to Step 4

4 | Replace the underhood junction block. Refer to Underhood Fuse Block Replacement in Engine Electrical. Is the repair complete? | -- | Go to Step 8 | --
5 |

1. Disconnect the BCM connector C1.
2. Use the J 39200 DMM in order to measure the voltage in CKT 592 between the underhood junction block harness connector C3 terminal B12 and ground.

Does the measured voltage equal the specified value?

0 V

Go to Step 6

Go to Step 7

6 | Replace the BCM. Refer to the following procedures:

• | Body Control Module (BCM) Programming/RPO Configuration

• | Body Control Module Replacement

Is the repair complete?

--

Go to Step 8

--

7 | Repair the short to B+ in CKT 592 between the BCM connector C1 terminal B5 and the underhood junction block harness connector C3 terminal B12. Is the repair complete? | -- | Go to Step 8 | --
8 | Clear the DTCs from the memory. Are the DTCs cleared from the memory? | -- | Go to Body Control Module System Check | --