GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2002 🢒 Eldorado 🢒 DTC 🢒 DTC B1971

Circuit Description

The MIRROR Fuse in the Underhood Fuse Block supplies battery positive voltage to the Inadvertent Power Relay coil. The BCM provides ground to the Inadvertent Power Relay in the control circuit. The BCM monitors the voltage in the Inadvertent Power Relay control circuit every second.

Conditions for Running the DTC

A short to ground in the Inadvertent Power Relay control circuit will be tested when the following conditions are met:

    • The Ignition is OFF.
    • The Inadvertent Power Relay is de-energized.

A short to battery positive voltage will be tested when the following conditions are met:

    • The Ignition is ON.
    • The Inadvertent Power Relay is energized.

Conditions for Setting the DTC

One of the following conditions can cause the DTC to set:

    • The Inadvertent Power relay is de-energized, and the BCM detects that the voltage in the control circuit of the Inadvertent Power relay is low for at least 4 seconds.
    • The Inadvertent Power relay is energized, and the BCM detects that the control circuit of the Inadvertent Power relay is high for at least 4 seconds.

Action Taken When the DTC Sets

The BCM turns OFF the Inadvertent Power Relay output, until the condition for setting the DTC is no longer present.

Conditions for Clearing the DTC

The DTC will clear when the following conditions are met:

    • The BCM detects that the voltage in the control circuit of the Inadvertent Power relay is no longer low for at least 4 seconds.
    • The BCM detects that the control circuit of the Inadvertent Power relay is no longer high for at least 4 seconds.

Test Description

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

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

    2.

  2. Tests for voltage at the coil side of the inadvertent power relay. The MIRROR fuse supplies power to the coil side of the inadvertent power relay.

    3.

  3. Verifies that the Body Control Module (BCM) is providing ground to the inadvertent power relay.

    4.

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

Step

Action

Yes

No

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

1

Did you perform the Lighting Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the inadvertent power relay ON and OFF.

Does the inadvertent power 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 Inadvertent Power relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the battery positive voltage circuit of the Inadvertent Power relay coil 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 Inadvertent Power relay and the battery positive voltage circuit of the Inadvertent Power relay coil.
  2. With a scan tool, command the inadvertent power 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 Inadvertent Power relay for a short to voltage or 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 Inadvertent Power 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 Inadvertent Power 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 or high resistance in the battery positive voltage circuit of the inadvertent power relay coil. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 13

--

11

Replace the Inadvertent Power relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 13

--

12

Replace the Body Control Module (BCM). Refer to Body Control Module Replacement in Body Control System.

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