Diagnostic Aids

The park brake must be unapplied and the transaxle must be in gear for the DRL 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.

DTC B2603

Step	Action	Yes	No
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics (w/T82) or Headlights/Daytime Running Lights (DRL) Schematics (w/o T82)
1	Did you perform the Diagnostic System Check - Vehicle?	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the DRL relay ON and OFF. Does the DRL relay turn ON and OFF with each command?	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems	Go to Step 3
3	Disconnect the daytime running lamps (DRL) relay. Turn ON the ignition, with the engine OFF. Probe the control circuit of the DRL relay with a test lamp that is connected to a good ground. Does the test lamp illuminate?	Go to Step 4	Go to Step 5
4	Leave the test lamp connected. Turn OFF the ignition. Disconnect the body control module (BCM). Turn ON the ignition, with the engine OFF. Does the test lamp illuminate?	Go to Step 5	Go to Step 6
5	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 10	Go to Step 8
6	Inspect for poor connections at the harness connector of the body control module (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 10	Go to Step 9
7	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 10	-
8	Replace the DRL relay. Did you complete the replacement?	Go to Step 10	-
9	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 10	-
10	Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?	Go to Step 3	System OK