GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The high intensity discharge (HID) controller monitors the arc tube and ballast performance by checking the current and voltage levels on the arc tube voltage supply circuit. If the HID controller detects 5 faults in the same key cycle the DTC B2575 will be set as a current DTC. When the key is cycled the DTC is then stored in memory. When the DTC is current the controller will disable the headlamp until the key is cycled to the OFF position.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B2575 Headlamp Control Circuit

Conditions for Running the DTC

The following conditions must be present before the DTC can set:

    • The ignition is in the ON position.
    • The headlamps are turned ON.

Conditions for Setting the DTC

The DTC will set immediately if the headlamp fails to strike an arc. The code will also set if the HID controller detects 5 failures during the same key cycle of any of the following faults.

    • The voltage at the ballast is less than 8.6 volts.
    • Auto test fails at power up.
    • The voltage at the HID arc tube is greater than 115 volts.
    • The voltage at the HID arc tube is less than 55 volts.
    • The current at the HID arc tube is greater than 2 amps.

Action Taken When the DTC Sets

The headlamp will be commanded OFF by the HID controller.

Conditions for Clearing the DTC

The DTC will be stored in memory after one key cycle and the DTC will have to be present again before the headlamp is commanded OFF.

Test Description

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

  1. This step test allows time for the HID controller to monitor the headlamp operation.

  2. This step tests for battery voltage at the appropriate headlamp.

Step

Action

Value(s)

Yes

No

Caution: The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns:

   • Never open the high intensity discharge system ballast or the arc tube assembly starter.
   • Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.

Schematic Reference: Headlight Leveling Schematics

Connector End View Reference: Lighting Systems Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn ON the ignition, with the engine OFF.
  2. Turn ON the headlamps.

Do both headlamps illuminate?

--

Go to Step 3

Go to Step 4

3

Monitor the headlamp operation for at least 3 minutes.

Are both headlamps illuminated?

--

Go to Step 6

Go to Testing for Intermittent Conditions and Poor Connections

4

  1. Turn OFF the headlamps.
  2. Turn ON the headlamps.
  3. Measure the voltage between the appropriate high intensity discharge (HID) ballast supply voltage circuit and a good ground.
  4. Turn OFF the headlamps.

Is the voltage greater than the specified value?

8.6 V

Go to Step 6

Go to Step 5

5

Repair the open or high resistance in the appropriate HID ballast supply voltage circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

--

Go to Step 10

--

6

Inspect for poor connections at the appropriate HID arc tube. Refer to Repairing Damaged Wire Insulation and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 7

7

Replace the HID arc tube. Refer to High Intensity Discharge Headlamp Starter/Arc Tube Replacement .

Do the HID headlamps operate properly?

--

Go to Step 10

Go to Step 8

8

Inspect for poor connections at the appropriate HID ballast. Refer to Repairing Damaged Wire Insulation and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 10

Go to Step 9

9

Replace the HID ballast. Refer to High Intensity Discharge Headlamp Ballast Replacement .

Did you complete the replacement?

--

Go to Step 10

--

10

  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