For 1990-2009 cars

### 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 Low Voltage/Open
DTC B2355 01: Driver Seat Front Vertical Position Sensor Circuit Short to Battery
DTC B2355 06: Driver Seat Front Vertical Position Sensor Circuit Low Voltage/Open
DTC B2365 01: Driver Seat Rear Vertical Position Sensor Circuit Short to Battery
DTC B2365 06: Driver Seat Rear Vertical Position Sensor Circuit Low Voltage/Open
DTC B2375 01: Driver Seat Assembly Horizontal Position Sensor Circuit Short to Battery
DTC B2375 06: Driver Seat Assembly Horizontal Position Sensor Circuit Low Voltage/Open

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
12 V Reference | B1405 02, B1825 06, B2355 06, B2365 06, B2375 06 | B1825 06, B2355 06, B2365 06, B2375 06 | B1825 01, B2355 01, B2365 01, B2375 01 | --
Driver Seat Front Vertical Position Sensor Signal | B2355 06 | B2355 06 | B2355 01 | --
Driver Seat Rear Vertical Position Sensor Signal | B2365 06 | B2365 06 | B2365 01 | --
Driver Seat Horizontal Position Sensor Signal | B2375 06 | B2375 06 | B2375 01 | --
Driver Seat Lumbar Horizontal Position Sensor Signal | B1850 06 | B1850 06 | B1850 01 | --
Driver Seat Recline Position Sensor Signal | B1825 06 | B1825 06 | B1825 01 | --

### Circuit Description

The memory seat 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 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

• | DTC B1325 must not be present.

• | Module battery voltage must be between 9 - 16 V.

### Conditions for Setting the DTC

The memory seat module does not detect position sensor movement or pulse signals while the adjuster motor is active. The following conditions will set this DTC:

#### B1825 01, B2355 01, B2365 01, or B2375 01

The memory seat module detects a short to battery on the sensor signal circuit.

#### B1825 06, B2355 06, B2365 06, or B2375 06

The memory seat module detects a short to ground or an open on the sensor signal circuit.

### Action Taken When the DTC Sets

The memory seat module 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 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 Schematics

#### Connector End View Reference

Component Connector End Views

#### 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 Verification

Ignition ON, observe the K40 Memory Seat Module Diagnostic Trouble Codes (DTC) list. Verify that DTC B1405 02 is not set along with any seat position sensor DTC.

⇒ | If DTC B1405 02 is set, refer to DTC B1405.

⇒ | If DTC B1405 02 is not set, refer to Circuit/System Testing.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate seat motor listed below for which the DTC set:

• | M50 front vertical motor

• | M55 rear vertical motor

• | M51 horizontal motor

• | M56 recline motor

2. Ignition ON, test for B+ between the 12 V reference circuit terminal 4 and ground.

⇒ | If less than the specified value, test the 12 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K40 memory seat module.

3. Test for 0.3 - 2 V between the signal circuit terminal 2 and ground.

⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K40 memory seat module.

⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K40 memory seat module.

4. If all circuits test normal, replace the seat motor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Front Seat Recliner Actuator Motor Replacement

• | Front Seat Adjuster Motor Replacement

• | Control Module References for memory seat module replacement, setup, and programming