Circuit/System Testing

WARNING: This page is about a different car, the 2018 Buick Envision. However, it is still accessible from the selected car via links, so may be relevant.

B3920 01 or B3920 02

Ignition OFF, disconnect the X3 harness connector at the K40D Seat Memory Control Module - Driver.
Test for infinite resistance between each control circuit terminal listed below and ground:
- Front vertical motor up control terminal 3
- Front vertical motor down control terminal 4
- Rear vertical motor up control terminal 5
- Rear vertical motor down control terminal 6
- Horizontal motor forward control terminal 11
- Horizontal motor rearward control terminal 12
- Recline motor forward control terminal 1
- Recline motor rearward control terminal 2
- If less than infinite resistance
  Repair the short to ground on the circuit.
- Go to next step: If infinite resistance
Ignition ON.
Test for less than 1 V between each control circuit terminal listed below and ground:
- Front vertical motor up control terminal 3
- Front vertical motor down control terminal 4
- Rear vertical motor up control terminal 5
- Rear vertical motor down control terminal 6
- Horizontal motor forward control terminal 11
- Horizontal motor rearward control terminal 12
- Recline motor forward control terminal 1
- Recline motor rearward control terminal 2
- If 1 V or greater
  Repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
Replace the K40D Seat Memory Control Module - Driver.

B3920 00 or B3920 0B

Ignition ON.
Clear the current and history DTC.
Determine which motor set this DTC by operating the driver seat motors listed below one at a time in both directions. Check for the DTC to set between each motor test.
- M50D Seat Front Vertical Motor - Driver
- M55D Seat Rear Vertical Motor - Driver
- M51D Seat Horizontal Motor - Driver
- M56D Seat Recline Motor - Driver
Ignition OFF, disconnect the harness connector at the seat motor for which the DTC set, ignition ON.
Clear the DTC.
Verify that DTC B3920 00 or B3920 0B does not set while operating the seat motor adjuster switch in both directions.
- If DTC B3920 00 or B3920 0B sets
1. Test for infinite resistance between control circuit terminal 1 and control circuit terminal 3
  - If less than infinite resistance, repair the short between the circuits.
  - Go to next step: If infinite resistance
2. Test for less than 2 Ω in each control circuit terminal end to end:
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the seat motor.
- Go to next step: If DTC B3920 00 or B3920 0B does not set
Replace the seat motor.