GM Service Manual Online
For 1990-2009 cars only

Circuit Description

Battery positive voltage is supplied to the memory seat module (MSM) from the PWR SEAT Circuit Breaker located in the rear fuse block. When commanded, this voltage is used by the MSM to power the seat motors through the motor control circuits. During memory recall functions and manual seat functions, the driven motor current is monitored through the motor control circuits by the MSM. When an overcurrent condition is detected, the MSM disables the seat motors in order to protect the internal MSM circuitry.

Conditions for Running the DTC

The MSM monitors for overcurrent only when the seat motors are active.

Conditions for Setting the DTC

The MSM will set DTC B3793 when the measured current exceeds 81 amps for 100 milliseconds.

Action Taken When the DTC Sets

    • All memory recalls in progress are aborted.
    • The MSM will not respond to manual movements of the affected motor.

Conditions for Clearing the DTC

The MSM does not detect an overcurrent condition during seat movement.

Test Description

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

  1. This test determines if the suspect motor has an internal short to ground.

  2. This test verifies the repair.

Step

Action

Yes

No

Schematic Reference: Memory Seats Schematics or Lumbar Support Schematics

Connector End View Reference: Power Seat Connector End Views

1

Did you perform the Diagnostic System Check - Power Seat Systems?

Go to Step  2

Go to Diagnostic System Check - Power Seat Systems

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Current Diagnostic Trouble Codes in the Memory Seat Module Diagnostic Trouble Codes list.
  4. Operate the seat switch in both directions for each directional motor.

Did the scan tool display DTC B3793 for any of the seat directional motors?

Go to Step  3

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

3

  1. Disconnect the suspect motor harness connector.
  2. With a scan tool, observe the Current Diagnostic Trouble Codes.
  3. Operate the suspect motor switch in both directions.

Does the scan tool display DTC B3793?

Go to Step  4

Go to Step  5

4

Test the motor control circuits of the suspect motor 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  9

Go to Step  6

5

Inspect for poor connections at the harness connector of the suspect seat motor. 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  9

Go to Step  7

6

Inspect for poor connections at the harness connector of the memory seat module. 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  9

Go to Step  8

7

Replace the suspect seat motor. Refer to Seat Adjuster Motor Replacement , Front Seat Recliner Actuator Motor Replacement , or Front Seat Lumbar Support Replacement .

Did you complete the replacement?

Go to Step  9

--

8

Replace the memory seat module. Refer to Memory Seat Control Module Replacement .

Did you complete the replacement?

Go to Step  9

--

9

  1. Clear the DTCs using the scan tool.
  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