Buick Regal: DTC B1405, B1825, B2355, B2365, or B2375 (Driver Seat)
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
- Diagnostic Procedure Instructions provides an overview of each
diagnostic category.
DTC Descriptors
DTC B1405
Control Module Voltage Reference Output 2 Circuit
DTC B1825
Seat Recline Position Sensor Circuit
DTC B2355
Seat Front Vertical Position Sensor Circuit
DTC B2365
Seat Rear Vertical Position Sensor Circuit
DTC B2375
Seat Assembly Horizontal Position Sensor Circuit
For symptom byte information refer to Symptom Byte List.
Diagnostic Fault Information
Circuit Description
The seat memory control module monitors the position of the seat motors by
using hall effect position
sensors which are an internal part of each motor. The module supplies each
sensor with a 12 V reference
circuit only when any seat motor is active, and a low side signal circuit.
During seat motor operation, the
hall effect position sensor provides a determined number of pulse signals for
every revolution of the
motor shaft. The scan tool displays these pulse signals as counts that range
from 0 - 65, 535. The module
counts the feedback pulses from each sensor to determine seat position and end
of travel limits for each
of the seat motors. High scan tool count values indicate forward or upward seat
positions while low
count values indicate rearward or downward seat positions.
Conditions for Running the DTC
- Any seat motor must be active.
- DTC B1325 must not be present.
- Module battery voltage must be between 9 - 16 V.
Conditions for Setting the DTC
The seat memory control module does not detect position sensor movement or
pulse signals while the
adjuster motor is active. The following conditions will set this DTC:
B1405 02
The seat memory control module detects a short to ground or an open on the 12
V reference circuit.
B1825 01, B2355 01, B2365 01, or B2375 01
The seat memory control module detects a voltage greater than 5 V on the
sensor signal circuit.
B1825 06, B2355 06, B2365 06, or B2375 06
The seat memory control module detects a short to ground or an open on the
sensor signal circuit.
Action Taken When the DTC Sets
- With a short to ground or an open circuit, the seat memory control
module disables the memory
recall and easy exit/entry action commands of the motor monitored by the
sensor. The motor will
respond to manual position commands.
- With a short to battery voltage, the seat memory control module disables
the memory recall and
easy exit/entry action commands for all four seat motors. The motors will
respond to manual
position commands.
Conditions for Clearing the DTC
- The current DTC clears when the fault is no longer present and the power
mode changes to OFF
then back to ACC or RUN.
- The history DTC will clear after 40 consecutive fault-free ignition
cycles have occurred.
Reference Information
Schematic Reference
Driver Seat Wiring Schematics
Connector End View Reference
Component Connector End View Index
Description and Operation
Memory Seats Description and Operation
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate driver
seat motor listed below
for which the DTC set:
- M50D Seat Front Vertical Motor - Driver
- M55D Seat Rear Vertical Motor - Driver
- M51D Seat Horizontal Motor - Driver
- M56D Seat Recline Motor - Driver
2. Ignition ON.
3. Test for greater than 10.8 V between the appropriate 12 V reference circuit
listed below and
ground while pressing any power seat switch.
- M50D Seat Front Vertical Motor - Driver terminal 2
- M55D Seat Rear Vertical Motor - Driver terminal 4
- M51D Seat Horizontal Motor - Driver terminal 4
- M56D Seat Recline Motor - Driver terminal 2
- If 10.8 V or less
- Ignition OFF, disconnect the X5 harness connector at the K40D Seat
Memory Control
Module - Driver.
- Test for infinite resistance between the 12 V reference circuit and
ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the 12 V reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K40D Seat Memory Control Module -
Driver.
- Go to next step: If greater than 10.8 V
4. Test for 0.2 - 2 V between the appropriate signal circuit listed below and
ground.
- M50D Seat Front Vertical Motor - Driver terminal 4
- M55D Seat Rear Vertical Motor - Driver terminal 2
- M51D Seat Horizontal Motor - Driver terminal 2
- M56D Seat Recline Motor - Driver terminal 4
- If less than 0.2 V
- Ignition OFF, disconnect the X5 harness connector at the K40D Seat
Memory Control
Module - Driver.
- Test for infinite resistance between the signal circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K40D Seat Memory Control Module -
Driver.
- Ignition OFF, disconnect the X5 harness connector at the K40D Seat
Memory Control
Module - Driver, ignition ON.
- Test for less than 1 V between each signal circuit listed below and
ground.
- Front vertical sensor terminal 12
- Seat horizontal sensor terminal 11
- Rear vertical sensor terminal 25
- Seat recline sensor terminal 26
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K40D Seat Memory Control Module -
Driver.
- Go to next step: If between 0.2 - 2 V
5. Test or replace the seat motor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Front Seat Tilt Adjuster Actuator Replacement
- Driver or Passenger Seat Vertical Adjuster Actuator Replacement
- Driver or Passenger Seat Recliner Actuator Replacement (Except GS) or
Driver or
Passenger Seat Recliner Actuator Replacement (GS)
- Control Module References for K40D Seat Memory Control Module - Driver
replacement,
programming and setup
READ NEXT:
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
SEE MORE:
Removal Procedure
1. Remove the rear tire and wheel assembly.
2. Rear Brake Caliper Bracket - Remove.
3. Rear Brake Rotor - Remove.
4. Rear Brake Shield - Remove.
5. Rear Wheel Bearing and Hub Assembly - Remove.
6.
Rear Suspension Upper Control Arm Outer Nut(1) - Remove.
7. Rear Suspension Up
If equipped, the ignition must be on
or in ACC/ACCESSORY to operate
the rear window wiper/washer.
Turn the end of the windshield wiper
lever to operate the rear window
wiper/washer.
OFF : Turns the system off.
INT : Intermittent wipes.
ON : Slow wipes.
: Push the windshield wiper
lever forward