Diagnostic Instructions

DTC Descriptors

DTC B1825 08: Seat Recline Position Sensor Circuit Signal Invalid

DTC B1825 58: Seat Recline Position Sensor Circuit Incorrect Reaction After Event

DTC B1850 08: Seat Lumbar Horizontal Position Sensor Circuit Signal Invalid

DTC B1850 58: Seat Lumbar Horizontal Position Sensor Circuit Incorrect Reaction After Event

DTC B1860 08: Seat Lumbar Vertical Position Sensor Circuit Signal Invalid

DTC B1860 58: Seat Lumbar Vertical Position Sensor Circuit Incorrect Reaction After Event

DTC B2355 08: Seat Front Vertical Position Sensor Circuit Signal Invalid

DTC B2355 58: Seat Front Vertical Position Sensor Circuit Incorrect Reaction After Event

DTC B2365 08: Seat Rear Vertical Position Sensor Circuit Signal Invalid

DTC B2365 58: Seat Rear Vertical Position Sensor Circuit Incorrect Reaction After Event

DTC B2375 08: Seat Horizontal Position Sensor Circuit Signal Invalid

DTC B2375 58: Seat Horizontal Position Sensor Circuit Incorrect Reaction After Event

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
5-Volt Reference	B1825 08, B1850 08, B1860 08, B2355 08, B2365 08, B2375 08, B2860 08, B2880 08	B1825 08, B1850 08, B1860 08, B2355 08, B2365 08, B2375 08, B2860 08, B2880 08	B1825 08, B1850 08, B1860 08, B2355 08, B2365 08, B2375 08, B2860 08, B2880 08	B1825 58, B1850 58, B1860 58, B2355 58, B2365 58, B2375 58, B2860 58, B2880 58
Front Vertical Motor Position Sensor Signal	B2355 08	B2355 08	B2355 08	--
Horizontal Motor Position Sensor Signal	B2375 08	B2375 08	B2375 08	--
Lumbar Horizontal Position Sensor Signal	B1850 08	B1850 08	B1850 08	--
Lumbar Vertical Position Sensor Signal	B1860 08	B1860 08	B1860 08	--
Rear Vertical Motor Position Sensor Signal	B2365 08	B2365 08	B2365 08	--
Recline Motor Position Sensor Signal	B1825 08	B1825 08	B1825 08	--
Memory Seat/Mirror Sensor Low Reference	--	B1825 08, B1850 08, B1860 08, B2355 08, B2365 08, B2375 08, B2860 08, B2880 08	1	B1825 58, B1850 58, B1860 58, B2355 58, B2365 58, B2375 58, B2860 58, B2880 58
1. Power Seat Inoperative

Circuit/System 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

Conditions for Setting the DTC

B1825 08, B1850 08, B1860 08, B2355 08, B2365 08, B2375 08

B1825 58, B1850 58, B1860 58, B2355 58, B2365 58, B2375 58

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.

Actions Taken When the DTC Sets

The motor associated with the fault will be disabled for memory functions.

Conditions for Clearing the DTCs

Diagnostic Aids

The memory seat module (MSM) is also referred to as the driver position module (DPM) in certain scan tool menus.

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool Driver Position Module driver seat and lumbar position sensor parameters. The readings should be between 0.25-2.75 volts and change while adjusting seat and lumbar positions.

Circuit/System Testing

B1825 08

1. Ignition OFF, disconnect the harness connector at the seat recline position sensor.
2. Test for less than 2 ohms between the low reference circuit terminal 3 and ground.

⇒	If greater than the specified range, 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 1 and ground.

⇒	If less than the specified range, 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 the specified range, 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 1 volt.

⇒	If greater than the specified range, 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 4.75 volts.

⇒	If less than the specified range, 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 08, B2365 08, or B2375 08

1. Ignition OFF, disconnect the X2 harness connector at the seat adjuster motor assembly.
2. Test for less than 2 ohms between the low reference circuit terminal 2 and ground.

⇒	If greater than the specified range, 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.

⇒	If less than the specified range, 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 the specified range, 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 position sensor parameter is less than 1 volt.

⇒	If greater than the specified range, test the appropriate signal circuit listed below 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 appropriate signal circuit listed below and the 5-volt reference circuit terminal 6. Verify the appropriate scan tool driver seat position sensor parameter is greater than 4.75 volts.

•	Seat front vertical position sensor terminal 1

•	Seat rear vertical position sensor terminal 5

•	Seat horizontal position sensor terminal 3

⇒	If less than the specified range, 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 position sensor.

B1850 08, or B1860 08

1. Ignition OFF, disconnect the X3 harness connector at the lumbar motor assembly.
2. Test for less than 2 ohms between the low reference circuit terminal A and ground.

⇒	If greater than the specified range, 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 C and ground.

⇒	If less than the specified range, 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 the specified range, 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 1 volt.

⇒	If greater than the specified range, test the appropriate signal circuit listed below for a short to voltage. If the circuit tests normal, replace the MSM.

•	Lumbar horizontal sensor terminal D

•	Lumbar vertical sensor terminal B

5. Install a 3A fused jumper wire between the appropriate signal circuit listed below and the 5-volt reference circuit terminal C. Verify the appropriate scan tool lumbar sensor parameter is greater than 4.75 volts.

•	Lumbar horizontal sensor terminal D

•	Lumbar vertical sensor terminal B

⇒	If less than the specified range, 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 position sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.