GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Corvette 🢒 DTC 🢒 DTC B2625

Circuit Description

The ignition mode switch has 3 LEDs that indicate the vehicle power mode. All these LEDs have the voltage supplied from the body control module (BCM) through the ignition mode switch supply voltage circuit. The ground path for each LED is controlled by the BCM.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B2625 Display Dimming Pulse Width Modulation (PWM) Output Circuit

This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description in Vehicle DTC Information.

DTC Symptom

DTC Symptom Descriptor

02

Short to ground

Conditions for Running the DTC

Voltage supplied to the module is in the normal operating voltage range of 9-16 volts.

Conditions for Setting the DTC
    • The BCM detects a short to ground in ignition mode switch supply voltage circuit.
    • The above condition is present for at least 1 second.

Action Taken When the DTC Sets
    • The BCM stores the respective DTC in memory.
    • None of the LEDs indicators will work.

Conditions for Clearing the DTC
    • A current DTC clears when the malfunction is no longer present.
    • A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

Diagnostic Aids

If the DTC is history only, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. The following conditions may cause an intermittent malfunction to occur:

    • An intermittent short to ground in the ignition mode switch supply voltage circuit
    • An intermittent short to ground internal to the ignition mode switch
    • An intermittent short to ground internal to the BCM

Step

Action

Yes

No

Schematic Reference: Power Distribution Schematics in Wiring Systems and Body Control System Schematics

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

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. Turn ON the ignition, with the engine OFF.
  2. Retrieve the DTCs from the body control module (BCM).

Is the B2625 set as current?

Go to Step 3

Go to Diagnostic Aids

3
  1. Turn OFF the ignition.
  2. Disconnect the ignition mode switch.
  3. Disconnect the ignition mode switch voltage supply circuit.
  4. Reconnect the ignition mode switch.
  5. Turn ON the ignition, with the engine OFF.
  6. Retrieve the DTCs from the BCM.

Is the B2625 set as current?

Go to Step 4

Go to Step 7

4
  1. Turn off the ignition.
  2. Disconnect the BCM.
  3. Test the ignition mode switch supply voltage circuit for short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 5

5

Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 6

6

Replace the BCM . Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 9

--

7

Inspect for poor connections at the harness connector of the ignition mode switch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 8

8

Replace the ignition mode switch. Refer to Switch Replacement - Ignition and Start, DIC Display and HUD Dimmer in Instrument Panel, Gages, and Console.

Did you complete the replacement?

Go to Step 9

--

9
  1. Reconnect all the disconnected modules.
  2. Use the scan tool in order to clear the DTCs.
  3. Operate the vehicle within the Conditions for Running the DTC.

Does the DTC reset?

Go to Step 2

System OK