Diagnostic Aids

WARNING: This page is about a different car, the 2003 GMC Sonoma, 2003 GMC Jimmy, 2003 Chevrolet S10 Pickup, and 2003 Chevrolet Blazer. However, it is still accessible from the selected car via links, so may be relevant.

Always diagnose the first DTC that is listed on the scan tool.
Verify that the scan tool displays DTC B2600 as a current code before you perform diagnostics.
The scan tool can command the DRL relay ON.
This test is located under the Special Functions menu.
Compare the state of the DRL relay as indicated on the scan tool with the actual state of the DRL relay.
Test for an inoperative high beam headlamp.
Use an incandescent shop light or a flashlight.
Direct the lighting toward the light sensor in order to force the light sensor into a LIGHT state.
Inspect for loose or poor connection at all of the related components. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems.