B2600 - FAULT CODE - OBD2

B2600 Code failures by brands

B2600 BUICK, CADILLAC, CHEVROLET, GMC, PONTIAC: LEFT DAYTIME RUNNING LAMPS CONTROL CIRCUIT

Description of DTC code B2600

The Ambient Light Sensor monitors different outdoor lighting conditions. This sensor provides a voltage signal, which changes between 0.2 and 4.9 volts according to the outdoor lighting conditions. The BCM (Body Control Module) sends the Ambient Light Sensor a 5-volt reference voltage, and the sensor receives a low reference ground from the HVAC Control Module.

The Body Control Module makes frequent monitoring of the Ambient Light Sensor signal circuit. Therefore, it determines whether the exterior lighting conditions are the most appropriate for daytime running lights or automatic light control when the headlight switch is set to AUTO. Under daylight conditions, the BCM activates the assigned daytime running lights. When there is low light, this controller activates the low beam headlights. When some conditions or functions turn on the headlights, daytime running lights operation is canceled.

Storage of diagnostic code B2600 OBD2 occurs when the circuitry controlling the left daytime running lights experiences erratic operation.

Symptoms of fault code B2600

Check Engine light ON.

Causes of OBD2 B2600

The B2600 OBDII fault code is stored for the following reasons:

The left parking/daytime running light circuit wiring may be faulty.
The left parking/daytime running light circuit may be shorted.
The left parking/daytime running light may be defective.
The BCM (Body Control Module) may be damaged.

Possible solutions of the DTC code B2600

To troubleshoot DTC B2600 OBD2, try this:

Consult the TSB (Technical Service Bulletins).
Check the wiring related to the left parking/daytime running light circuit and check it for common deficiencies, corrosion, or burns. Fix if necessary.
Measure the left parking/daytime running light circuit voltages to check they are within the parameters set by the manufacturer. If you discover an open or shorted circuit, make the right corrections.
Check the condition of the left parking/daytime running light. If deficiencies are found, consider replacing it.