Circuit Description
The daytime running lights (DRL) relay is controlled by the body control module (BCM). Battery positive voltage is applied to the relay coil at all times. The BCM grounds the DRL relay control circuit in order to turn ON the DRL relay. When the DRL relay control circuit becomes shorted to battery positive voltage, DTC B2603 is set.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2603 Daytime Running Lamp Control 1 Circuit High
Conditions for Running the DTC
The ignition switch is in the ON position.
Conditions for Setting the DTC
| • | The BCM is commanding the DRL relay on. |
| • | The headlamp feedback is not present for 1 second. |
Action Taken When the DTC Sets
| • | The BCM disables the DRL relay control as long as the malfunction is present. |
| • | The SERVICE indicator illuminates. |
Conditions for Clearing the DTC
| • | The conditions for setting the DTC are no longer present. |
| • | A history DTC clears after 100 malfunction free ignition cycles. |
| • | The BCM receives the clear code command from the scan tool. |
Diagnostic Aids
| • | The park brake must be unapplied and the transaxle must be in gear for the DRLs to operate properly. |
| • | If the DTC is a history DTC, the problem may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the test lamp illuminate? | Go to Step 3 | Go to Step 4 |
3 |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 5 |
4 | Inspect for poor connections at the DRL relay. 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 9 | Go to Step 7 |
5 | 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 9 | Go to Step 8 |
6 | Repair a short to voltage in the DRL relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 9 | -- |
7 | Replace the DRL relay. Did you complete the replacement? | Go to Step 9 | -- |
8 | Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 9 | -- |
9 |
Does the DTC reset? | Go to Step 2 | System OK |
