GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2009 🢒 Regal 🢒 DTC 🢒 DTC B260B or B260C

Diagnostic Instructions
  1. Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
  2. Review Strategy Based Diagnosis for an overview of the diagnostic approach.
  3. Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B260B 01: Left Daytime Running Lamp Relay Control Circuit Short to Battery

DTC B260B 02: Left Daytime Running Lamp Relay Control Circuit Short to Ground

DTC B260B 04: Left Daytime Running Lamp Relay Control Circuit Open

DTC B260C 01: Right Daytime Running Lamp Relay Control Circuit Short to Battery

DTC B260C 02: Right Daytime Running Lamp Relay Control Circuit Short to Ground

DTC B260C 04: Right Daytime Running Lamp Relay Control Circuit Open

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Left Daytime Running Lamps Relay Control

B260B 02

B260B 04

B260B 01

--

Right Daytime Running Lamps Relay Control

B260C 02

B260C 04

B260C 01

--

Circuit/System Description

The daytime running lamp relay - left and the daytime running lamp relay - right are supplied with battery voltage from the body control module (BCM). The headlamp switch signal circuit is grounded by turning the headlamp switch. The BCM energizes the daytime running lamp relay - left and the daytime running lamp relay - right by applying battery voltage to the daytime running lamp relay - left and the daytime running lamp relay - right control circuit. When the daytime running lamp relay - left and the daytime running lamp relay - right is energized, battery voltage is applied to the front lamp supply voltage circuit which illuminates the front daytime running lamps.

Conditions for Running the DTC

B260B 01 or B260C 01

Engine is not running.

B260B 02, B260B 04, B260C 02 or B260C 04

    • The engine is running.
    • Headlamp switch in AUTO position.
    • The ambient light is day.

Conditions for Setting the DTC

B260B 01 or B260C 01

The BCM detects a short to voltage on the control circuit.

B260B 02 or B260C 02

The BCM detects a short to ground on the control circuit.

B260B 04 or B260C 04

The BCM detects an open control circuit.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, perform the appropriate Dedicated Daytime Running Lamp Command test. The appropriate daytime running lamp should be ON / OFF.

Circuit/System Testing
  1. Ignition OFF, disconnect the appropriate harness connector at the daytime running lamp listed below:
    2. • E3LH Daytime Running Lamp Left.
    • E3RH Daytime Running Lamp Right.
  2. Test for less than 5 Ω between the appropriate ground circuit harness connector terminal listed below and ground:
    3. • E3LH Daytime Running Lamp Left harness connector terminal 1
    • E3RH Daytime Running Lamp Right harness connector terminal 1
         ⇒If greater than the specified value, test the appropriate ground circuit for an open/high resistance.
  3. Disconnect the appropriate daytime running lamp relay listed below:
    4. • KR42L Daytime Running Lamp Relay - Left.
    • KR42R Daytime Running Lamp Relay - Right.
  4. Install a 10 A fused jumper wire between the appropriate daytime running lamp relay control circuit terminal 30 and control circuit terminal 87a.
  5. Connect a test lamp between the appropriate daytime running lamp control circuit harness connector terminal listed below and ground.
    6. • E3LH Daytime Running Lamp Left harness connector terminal 3
    • E3RH Daytime Running Lamp Right harness connector terminal 3
  6. Command the appropriate daytime running lamp ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    7. ⇒ If the test lamp is always ON, test the appropriate control circuit for a short to ground. If the circuit tests normal, replace the K9 Body Control Module (BCM).
    ⇒ If the test lamp is always OFF, test the appropriate control circuit for a short to voltage or an open / high resistance. If the circuit tests normal, replace the K9 Body Control Module (BCM).
  7. Remove the fused jumper wire.
  8. Install a 10 A fused jumper wire between the appropriate daytime running lamp relay control circuit terminal 30 and control circuit terminal 87.
  9. Connect a test lamp between the appropriate daytime running lamp control circuit harness connector terminal listed below and ground.
    10. • E3LH Daytime Running Lamp Left harness connector terminal 9
    • E3RH Daytime Running Lamp Right harness connector terminal 9
  10. Command the appropriate daytime running lamp ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    11. ⇒ If the test lamp is always ON, test the appropriate control circuit for a short to ground. If the circuit tests normal, replace the K9 Body Control Module (BCM).
    ⇒ If the test lamp is always OFF, test the appropriate control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module (BCM).
  11. If all circuits test normal, test or replace the appropriate daytime running lamp relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Relay Replacement
    •  Control Module References for BCM replacement, setup and programming