GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2007 🢒 Sierra - 2WD 🢒 Seats 🢒 Power Seats 🢒 DTC B1825, B1850, B1860, B2355, B2365, or B2375

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 B1825 01:  Driver Seat Recline Position Sensor Circuit Short to Battery

DTC B1825 06:  Driver Seat Recline Position Sensor Circuit Short to Ground or Open

DTC B1825 5A:  Driver Seat Recline Position Sensor Circuit Plausibility Failure

DTC B1850 01: Driver Seat Lumbar Horizontal Position Sensor Circuit Short to Battery

DTC B1850 06: Driver Seat Lumbar Horizontal Position Sensor Circuit Short to Ground or Open

DTC B1850 5A: Driver Seat Lumbar Horizontal Position Sensor Circuit Plausibility Failure

DTC B1860 01:  Driver Seat Lumbar Vertical Position Sensor Circuit Short to Battery

DTC B1860 06:  Driver Seat Lumbar Vertical Position Sensor Circuit Short to Ground or Open

DTC B1860 5A:  Driver Seat Lumbar Vertical Position Sensor Circuit Plausibility Failure

DTC B2355 01: Driver Seat Front Vertical Position Sensor Circuit Short to Battery

DTC B2355 06: Driver Seat Front Vertical Position Sensor Circuit Short to Ground or Open

DTC B2355 5A: Driver Seat Front Vertical Position Sensor Circuit Plausibility Failure

DTC B2365 01: Driver Seat Rear Vertical Position Sensor Circuit Short to Battery

DTC B2365 06: Driver Seat Rear Vertical Position Sensor Circuit Short to Ground or Open

DTC B2365 5A: Driver Seat Rear Vertical Position Sensor Circuit Plausibility Failure

DTC B2375 01:  Driver Seat Assembly Horizontal Position Sensor Circuit Short to Battery

DTC B2375 06:  Driver Seat Assembly Horizontal Position Sensor Circuit Short to Ground or Open

DTC B2375 5A:  Driver Seat Assembly Horizontal Position Sensor Circuit Plausibility Failure

Circuit Description

The position sensor that sets this diagnostic trouble code (DTC) is either attached to the seat directional motor drive cable or directly to the motor it monitors. It receives a 5-volt reference and ground from the memory seat module (MSM). The sensor sends a voltage signal that varies with the movement of the seat through the signal circuit to the MSM. Then based on this voltage signal, the MSM determines the position of the seat.

Conditions for Running the DTC

The memory seat module must be powered.

Conditions for Setting the DTC

B1825, B1850, B1860, B2355, B2365, B2375 01

If the MSM sees the analog input from this sensor is greater than 4.65 volts, the sensor will be considered out of range and the MSM will set this DTC.

B1825, B1850, B1860, B2355, B2365, B2375 06

If the MSM sees the analog input from this sensor is less than 0.27 volt , the sensor will be considered out of range and the MSM will set this DTC.

B1825, B1850, B1860, B2355, B2365, B2375 5A

This DTC will set, if the MSM is controlling a motor in one direction and it's position sensor is tracking the motor in the opposite direction. The sensor is either mounted or wired incorrectly, or the polarity of the motor control circuits are reversed.

Action Taken When the DTC Sets

The MSM disables the memory recall and easy exit/entry action commands of the motor monitored by the sensor. The motor will respond to manual positioning commands.

Conditions for Clearing the DTC
    • The current DTC will clear and set to history, when the MSM sees the analog input from the sensor as between 0.27-4.65 volts and the ignition is cycled OFF then back to ACC or RUN.
    • A history DTC will clear after 50 ignition cycles or with a scan tool using the clear DTCs function.

Diagnostic Aids
    • All position sensors use common ground and 5-volt reference circuits.
    • If the 5-volt reference circuit is shorted to voltage, multiple codes will set.
    • If the 5-volt reference circuit is shorted to ground, multiple codes will set.
    • If the sensor ground circuit is open, multiple codes will set.

Reference Information

Schematic Reference

Driver Seat Schematics

Connector End View Reference

Power Seat Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

DTC Symptom Description

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

Ignition ON, observe the scan tool Driver Seat and Lumbar position sensor parameters. The readings should be between 0.27-2.65 volts and change while adjusting seat and lumbar positions.

Circuit/System Testing

B1825

  1. Ignition OFF, disconnect the C2 harness connector at the seat recline motor.
  2. Ignition OFF, test for less than 2 ohms of resistance between the low reference circuit terminal 1 and ground.
    3. ⇒If greater than 2 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the MSM.
  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 3 and ground.
    4. ⇒If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the MSM.
    ⇒If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the MSM.
  4. Verify the scan tool Driver Seat Recline Sensor parameter is less than 2.0 volts.
    5. ⇒If greater than 2.0 volts, test the signal circuit terminal 2 for a short to voltage. If the circuit tests normal, replace the MSM.
  5. Install a 3A fused jumper wire between the signal circuit terminal 2 and the 5-volt reference circuit terminal 3. Verify the scan tool Driver Seat Recline Sensor parameter is greater than 4.65 volts.
    6. ⇒If less than 4.65 volts, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the MSM.
  6. If all circuits test normal, test or replace the seat recline position sensor.

B2355, B2365, B2375

  1. Ignition OFF, disconnect the C2 harness connector at the seat adjuster motor assembly.
  2. Ignition OFF, test for less than 2 ohms of resistance between the low reference circuit terminal 2 and ground.
    3. ⇒If greater than 2 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the MSM.
  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 6 and ground.
    4. ⇒If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the MSM.
    ⇒If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the MSM.
  4. Verify the appropriate scan tool Driver Seat Sensor parameter is less than 2.0 volts.
    5. ⇒If greater than 2.0 volts, test the appropriate signal circuit for a short to voltage. If the circuit tests normal, replace the MSM.
    • Seat front vertical position sensor terminal 1
    • Seat rear vertical position sensor terminal 5
    • Seat horizontal position sensor terminal 3
  5. Install a 3A fused jumper wire between the signal circuit and the 5-volt reference circuit terminal 6. Verify the appropriate scan tool Driver Seat position sensor parameter is greater than 4.65 volts.
    6. • Seat front vertical position sensor terminal 1
    • Seat rear vertical position sensor terminal 5
    • Seat horizontal position sensor terminal 3
    ⇒If less than 4.65 volts, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the MSM.
  6. If all circuits test normal, test or replace the seat adjuster motor assembly.

B1850, B1860

  1. Ignition OFF, disconnect the C2 harness connector at the seat lumbar motor assembly.
  2. Ignition OFF, test for less than 2 ohms of resistance between the low reference circuit terminal C and ground.
    3. ⇒If greater than 2 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the MSM.
  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal A and ground.
    4. ⇒If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the MSM.
    ⇒If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the MSM.
  4. Verify the appropriate scan tool Lumbar Sensor parameter is less than 2.0 volts.
    5. ⇒If greater than 2.0 volts, test the appropriate signal circuit for a short to voltage. If the circuit tests normal, replace the MSM.
    • Lumbar vertical position sensor terminal B
    • Lumbar horizontal position sensor terminal D
  5. Install a 3A fused jumper wire between the signal circuit and the 5-volt reference circuit terminal C. Verify the appropriate scan tool Lumbar Sensor parameter is greater than 4.65 volts.
    6. • Lumbar vertical position sensor terminal B
    • Lumbar horizontal position sensor terminal D
    ⇒If less than 4.65 volts, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the MSM.
  6. If all circuits test normal, test or replace the lumbar motor assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Front Seat Adjuster Replacement
    •  Front Seat Lumbar Support Replacement
    •  Front Seat Recliner Actuator Motor Replacement
    •  Control Module References for MSM replacement, setup, and programming