B1860
DTC B1825, B1850, B1860, B2355, B2365, or B2375
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC B1825
- Driver Seat Recline Position Sensor Circuit
DTC B1850
- Driver Seat Lumbar Horizontal Position Sensor Circuit
DTC B2355
- Driver Seat Front Vertical Position Sensor Circuit
DTC B2365
- Driver Seat Rear Vertical Position Sensor Circuit
DTC B2375
- Driver Seat Horizontal Position Sensor Circuit
Diagnostic Fault Information
Circuit/System Description
The driver seat adjuster motors are equipped with potentiometer type position sensors used by the memory seat module (MSM) to determine the seat position. The position sensors are supplied with 5-volt reference and ground circuits from the MSM. The position sensor signal circuits are referenced from ground within the MSM. The signal circuit voltage levels monitored by the MSM range from 0.39-4.58 volts and are determined by the wiper locations on the resistors within the motor position sensors. The position sensor circuit voltage levels are used by the MSM to determine the seat position when storing or recalling memory position settings.
Conditions for Running the DTC
The battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
The position sensor signal circuit voltage level to the MSM is not within the 0.39-4.58 volt range.
Action Taken When the DTC Sets
The memory recall functions for the seat motor with a current status DTC will be disabled.
Conditions for Clearing the DTC
* This DTC will clear on current status after the condition for setting the fault is corrected.
* A history DTC will clear after 100 consecutive ignition cycles without a fault present.
Circuit/System Verification
Ignition ON, observe the scan tool position sensor parameters. The readings should be between 0.39-4.58 volts and change when the seat position is changed.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the affected position sensor.
2. Ignition OFF, test for less than 20 ohms of resistance between the listed low reference circuit terminal and ground.
* Horizontal or rear vertical position sensor terminal A
* Front vertical position sensor terminal C
* Recline position sensor terminal D
* Horizontal lumbar position sensor terminal 1
^ 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 listed 5-volt reference circuit terminal and ground.
* Horizontal or rear vertical position sensor terminal C
* Front vertical or recline position sensor terminal A
* Horizontal lumbar position sensor terminal 3
^ 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 position sensor parameter is less than 0.39 volts.
^ If greater than the specified range, test the affected signal circuit terminal listed for a short to voltage. If the circuit tests normal, replace the MSM.
* Horizontal or front and rear vertical position sensors terminal B
* Recline position sensor terminal C
* Horizontal lumbar position sensor terminal 2
5. Install a 3A fused jumper wire between the listed signal circuit terminal and 5-volt reference circuit terminal. Verify the scan tool position sensor parameter is greater than 4.58 volts.
* Horizontal or rear vertical position sensor terminal B to terminal C
* Front vertical position sensor terminal B to terminal A
* Recline position sensor terminal C to terminal A
* Horizontal lumbar position sensor terminal 2 to 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 affected position sensor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Power Seat Adjuster Mechanism Replacement
* Front Seat Lumbar Support Replacement