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For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 1999 🢒 S/T Isuzu - 4WD 🢒 Body and Accessories 🢒 Body Control System 🢒 DTC B3137 Door Lock Circuit Low

Refer to Body Control Module Schematics (

Cell 51: DTC B3137, B3138, B3147, and B3148 -- Power Door Locks


Object Number: 403366 Size: FS
Cell 130: Relay Control and Door Lock Actuators
Cell 10: INT BATT, PWR LKS, CTSY LP and CIGAR LTR Fuses
Cell 10: MIR/LKS and FOG LP Fuses
Body Control Module Components
Body Control System Circuit Description
Body Control System Connector End Views
Handling ESD Sensitive Parts Notice
Cell 130: Relay Control and Door Lock Actuators
 ).

Circuit Description

The body control module (BCM) monitors and supplies an output on CKT 195. When the BCM receives a lock command from the remote control door lock receiver, the BCM supplies voltage on CKT 195 in order to lock the doors. The BCM will set a DTC when the following conditions exist:

    • CKT 195 is shorted to ground.
    • BCM receives a lock command from the remote control door lock receiver.

Conditions for Setting the DTC
    • The BCM commands the door lock relay active.
    • When the BCM receives a lock signal from the remote control door lock receiver module and CKT 195 is shorted to ground.
    • The system voltage is between 9.0-16.0 volts.
    • The above conditions exist for 0.25 seconds.

Action Taken When the DTC Sets
    • The door lock system will not lock the doors from the key fob.
    • The door lock switches will not lock the doors.

Conditions for Clearing the MIL/DTC
    • A current DTC will clear after the next door lock cycle that does not contain a fault.
    • A history DTC will clear after 100 consecutive ignition cycles without a fault present.
    • History and current DTCs may be cleared using a scan tool.

Diagnostic Aids
    • Always diagnose the first DTC that is listed on the scan tool.
    • Verify that the scan tool displays DTC B3137 as a current code before you perform diagnostics.
    • Inspect for loose or poor connections at all of the related components.
    • Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

Test Description

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

  1. This step determines if the lock relay is shorted to ground.

    2.

  2. This step determines if the left front door switch is shorted to ground.

    3.

  3. This step determines if the right front door switch is shorted to ground.

    4.

  4. This step determines if there is a short to ground in CKT 195.

Step

Action

Value(s)

Yes

No

1

Did you perform the BCM Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Body Control System

2

  1. Turn the ignition switch to the OFF position.
  2. Remove the door lock relay from the body relay block.
  3. Use a scan tool in order to monitor the current DTCs.
  4. Press and release the LOCK button on the key fob.

Does the scan tool display DTC B3137 as a current code?

--

Go to Step 3

Go to Step 9

3

  1. Disconnect the left front door lock switch.
  2. Use the scan tool in order to monitor the current DTCs.
  3. Press and release the LOCK button on the key fob.

Does the scan tool display DTC B3137 as a current code?

--

Go to Step 4

Go to Step 7

4

  1. Disconnect the right front door lock switch.
  2. Use a scan tool in order to monitor the current DTCs.
  3. Press and release the LOCK button on the key fob.

Does the meter display the specified value on all of the measurements?

OL

(infinite)

Go to Step 5

Go to Step 8

5

  1. Disconnect the BCM connector C1 (BRN). Remove the comb from the connector.
  2. Connect a test lamp to a good power source.
  3. Backprobe the BCM connector between CKT 195 (LT BLU) cavity A4 and ground.

Does the test lamp light?

--

Go to Step 6

Go to Step 10

6
  1. Locate and repair the short to ground in CKT 195 (LT GRN) between the BCM and one of the following components:
    2. • The lock relay
    • The left front and right front door lock switches
  2. Replace the blown MIR/LKS fuse (located in the underhood fuse block).

Is the repair complete?

--

Go to Step 11

--

7
  1. Replace the left front door lock switch.
  2. Replace the blown MIR/LKS fuse (underhood fuse block).

Is the repair complete?

--

Go to Step 11

--

8
  1. Replace the right front door lock switch.
  2. Replace the blown MIR/LKS fuse (located in the underhood fuse block).

Is the repair complete?

--

Go to Step 11

--

9
  1. Replace the door lock relay.
  2. Replace the blown MIR/LKS fuse (located in the underhood fuse block).

Is the repair complete?

--

Go to Step 11

--

10
  1. Replace the BCM.
  2. Replace the blown MIR/LKS fuse (located in the underhood fuse block).
  3. Program the correct calibrations into the BCM.
  4. Perform the learn procedure.

Is the repair complete?

--

Go to Step 11

--

11
  1. Reconnect all of the connectors.
  2. Clear the DTCs.

Is the repair complete?

--

Go to Diagnostic System Check - Body Control System

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