GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2004 🢒 XLR 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 DTC B2580

Circuit Description

When the headlamp dimmer switch is placed in the HIGH or FTP position ground is applied to the BCM through the high beam signal circuit or the flash to pass signed circuit. The BCM then applies a ground to the high beam relay control circuit. This energizes the high beam relay, applying battery positive voltage to the high beam solenoid of the headlamps. This causes the high beam solenoid to fully retract allowing the headlamps to illuminate at high beam capacity.

Conditions for Running the DTC

The battery voltage must be between 9.0-16.0 volts.

Conditions for Setting the DTC
    • DTC B2580 01 The high beam headlamp relay control circuit is shorted to battery positive voltage.
    • DTC B2580 06 The high beam headlamp relay control circuit is shorted to ground or open.

Action Taken When the DTC Sets
    • If DTC B2580 01 is set, the high beam headlamps will not operate.
    • If DTC B2580 06 is set, the high beam headlamps will remain on.

Conditions for Clearing the DTC
    • This DTC will clear on current status after the condition for setting the fault is corrected.
    • A history DTC will clear after 100 consecutive ignition cycles without a fault present.
    • History and current DTCs can be cleared using a scan tool.

Step

Action

Yes

No

Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics

Connector End View Reference: Master Electrical Component List in Wiring Systems

1

Did you perform the Diagnostic System Check?

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 high beam relay ON and OFF.

Does the high beam 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

Is DTC 2580.01 present?

Go to Step 4

Go to Step 7

4

  1. Remove the high beam headlamp relay from the underhood electrical center.
  2. Connect a test lamp between the high beam headlamp relay control circuit and ground.

Does the test lamp illuminate?

Go to Step 5

Go to Step 15

5

  1. Disconnect the BCM connector C1.
  2. Connect a test lamp between the high beam headlamp relay control circuit and ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 16

6

Test the high beam headlamp relay control circuit for a short to battery positive voltage. Refer to Circuit Testing and Circuit Testing in Wiring Systems.

Did you find and correct the condition?

Go to Step 21

Go to Step 17

7

Are the high beam headlamps ON at all times?

Go to Step 12

Go to Step 8

8
  1. Remove the high beam headlamp relay in the underhood accessory wiring junction block.
  2. Install a fused jumper between the high beam headlamp relay battery positive voltage supply circuit and the switched high beam supply voltage circuit.

Do the high beam headlamps illuminate?

Go to Step 9

Go to Step 17

9
  1. Remove the fused jumper.
  2. Install a test lamp between the high beam headlamp relay switched battery positive voltage supply circuit and the high beam headlamp relay control circuit.
  3. Turn the headlamp switch to the HIGH position.

Does the test lamp illuminate?

Go to Step 15

Go to Step 10

10
  1. Disconnect the electrical center underhood fuse block.
  2. Connect a test lamp between battery positive voltage and the high beam headlamp relay control circuit.
  3. Turn the headlamp switch to the HIGH position.

Does the test lamp illuminate?

Go to Step 17

Go to Step 11

11

Test for high resistance or an open in the high beam headlamp relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 21

Go to Step 16

12

Disconnect the BCM connector C1.

Do the high beam headlamps turn OFF?

Go to Step 16

Go to Step 13

13

Test for a short to ground in the high beam headlamp relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 21

Go to Step 14

14

Remove the high beam headlamp relay from the underhood fuse block.

Do the high beam headlamps turn OFF?

Go to Step 15

Go to Step 17

15

Inspect for a high resistance or a poor connection at the high beam headlamp relay in the underhood fuse block. 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 21

Go to Step 18

16

Inspect for a high resistance or a poor connection at the harness connector of the 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 21

Go to Step 19

17

Inspect for a high resistance or a poor connection at the harness connectors of the underhood fuse block. 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 21

Go to Step 20

18

Replace the high beam headlamp relay in the underhood fuse block. Refer to Relay Replacement in Wiring Systems.

Did you complete the repair?

Go to Step 21

--

19

Important:: After replacing the BCM, perform the setup procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration in Computer/Integrating Systems.

Replace the BCM. Refer to Body Control Module Replacement in Computer/Integrating Systems.

Did you complete the replacement?

Go to Step 21

--

20

Replace the underhood electrical center. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.

Did you complete the repairs?

Go to Step 21

--

21
  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.

    3. Does the DTC reset?

Go to Step 2

System OK