GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Blazer - 4WD - RHD 🢒 Body and Accessories 🢒 Body Control System 🢒 DTC B3102

Circuit Description

The remote control door lock receiver (RCDLR) communicates with the body control module (BCM) through the keyless entry serial data circuit. When any button on the keyless entry transmitter is pressed, the transmitter sends a signal to the RCDLR. The RCDLR sends either a lock or unlock request to the BCM, depending on which button is pressed on the transmitter. The BCM receives the message and performs the appropriate function.

Conditions for Running the DTC

The system voltage is at least 9.0 volts and no more than 16.0 volts.

Conditions for Setting the DTC
    • The keyless entry serial data circuit is shorted to ground.
    • The above conditions must be met for approximately 500 milliseconds.

Action Taken When the DTC Sets

The keyless entry system will not operate.

Conditions for Clearing the DTC
    • A current DTC will clear when the fault is no longer present and the ignition switch is cycled.
    • A history DTC will clear after 100 consecutive ignition cycles without a fault present.
    • A scan tool may be used to clear history and current DTC(s).

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. The normal state of the input displayed on the scan tool before pressing a transmitter button is NONE.

    2.

  2. When the UNLOCK button is pressed on the transmitter, Actv Unlock Fob# will be displayed on the scan tool.

    3.

  3. The normal state of the input displayed on the scan tool before pressing a transmitter button is NONE.

    4.

  4. Tests the signal circuit for a short to ground.

Step

Action

Yes

No

Schematic Reference: Keyless Entry Schematics

1

Did you perform the Remote Keyless Entry Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Remote Keyless Entry

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With the scan tool, observe the RFA Message Since Wake-up parameter.

Does the scan tool display NONE?

Go to Step 3

Go to Step 4

3

  1. Activate the UNLOCK button on the keyless entry transmitter.
  2. With the scan tool, observe the RFA Message Since Wake-up parameter.

Does the RFA Message Since Wake-up parameter change state?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the remote control door lock receiver (RCDLR).
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the RFA Message Since Wake-up parameter.

Does the scan tool display NONE?

Go to Step 7

Go to Step 5

5

Test the keyless entry serial data circuit 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 10

Go to Step 6

6

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 10

Go to Step 8

7

Inspect for poor connections at the harness connector of the RCDLR. 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 10

Go to Step 9

8

Important: Perform the BCM programming procedure when replacing the BCM.

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

Did you complete the replacement?

Go to Step 10

--

9

Replace the Remote Control Door Lock Receiver. Refer to Remote Control Door Lock Receiver Replacement .

Did you complete the replacement?

Go to Step 10

--

10
  1. Use a 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