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.
-
This step determines if the DRL relay is operating properly.
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This step determines if there is a short to the battery in CKT 592 within the underhood junction block.
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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 | |
Did the DRL relay activate? | -- | Go to Step 8 | Go to Step 3 | |
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? | -- | -- | |
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: 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? | -- | -- |
