GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2006 🢒 Torrent 🢒 DTC 🢒 DTC B2602

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.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B2602 Daytime Running Lamp Circuit Low

Conditions for Running the DTC
    • The ignition switch is in the RUN position.
    • The headlamp switch is in the AUTO position.
    • The park brake is not applied.
    • The gear selector is not in the PARK position.

Conditions for Setting the DTC

All of the following conditions must be met:

    • The BCM is not commanding the DRL relay ON.
    • The DRL relay control circuit is open or shorted to ground, or the DRL relay coil is open, or battery positive voltage to the DRL relay is open.

Action Taken When the DTC Sets

The BCM disables the DRL relay control as long as the malfunction is present.

Conditions for Clearing the DTC
    • The BCM receives the clear code command from the scan tool.
    • A current DTC will clear when the conditions for setting the DTC are no longer present.
    • A history DTC clears after 100 malfunction free ignition cycles.

Diagnostic Aids
    • The park brake must not be set 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.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Listen for an audible click when the DRL relay operates. Command both the ON and OFF states. Repeat the commands as necessary.

  2. Tests for voltage at the coil side of the DRL relay.

    3.

  3. Verifies that the body control module is providing ground to the DRL relay.

    4.

  4. Tests if ground is constantly being applied to the DRL relay.

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

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the daytime running lights (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

  1. Turn OFF the ignition.
  2. Disconnect the DRL relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the coil side battery positive voltage 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 10

4

  1. Connect a test lamp between the control circuit of the DRL relay and the coil side battery positive voltage circuit of the DRL relay.
  2. With a scan tool, command the DRL relay ON and OFF .

Does the test lamp turn ON and OFF with each command?

Go to Step 8

Go to Step 5

5

Does the test lamp remain illuminated with each command?

Go to Step 7

Go to Step 6

6

Test the control circuit of the DRL relay for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 9

7

Test the control circuit of the DRL relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 9

8

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 13

Go to Step 11

9

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 13

Go to Step 12

10

Repair an open, high resistance, or short to ground in the coil side battery positive voltage circuit of the DRL relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 13

--

11

Replace the DRL relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 13

--

12

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 13

--

13
  1. Use the scan tool in order to clear the DTCs .
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK