B2170

DTC B1925 or B2170

DTC DESCRIPTORS

DTC B1925 02: Left Seat Heater Cushion Sensor Circuit Shorted to Ground

DTC B2170 02: Right Seat Heater Cushion Sensor Circuit Shorted to Ground

DIAGNOSTIC FAULT INFORMATION




Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

CIRCUIT/SYSTEM DESCRIPTION
The heated seat temperature sensor that set this diagnostic trouble code (DTC) is located in the seat cushion just under the seat cover with the seat heating element. The memory seat module (MSM) supplies a separate 5-volt reference voltage through the temperature sensor signal circuit and a ground through the low reference circuit to the sensor. The module monitors the voltage of the sensor signal circuit to determine the temperature of the seat. The temperature sensor varies in resistance based on the temperature of the heating element, causing the signal voltage to change. Once the seat reaches the set temperature, the module will then cycle the control circuits of the heating elements ON and OFF in order to maintain the desired seat temperature based on the feedback voltage from the sensors.

CONDITIONS FOR RUNNING THE DTC
The memory seat module must be powered.

CONDITIONS FOR SETTING THE DTC

B1925/B2170 02
The temperature sensor voltage drops below 0.80 volt for more than 1 second.

ACTION TAKEN WHEN THE DTC SETS
The heated seat function for the affected seat will be disabled.

CONDITIONS FOR CLEARING THE DTC
- The current DTC will clear and set the code to history, 3 seconds after the reference voltage returns to the normal operating range and the ignition is cycled OFF then back to ACC or RUN.
- The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

CIRCUIT/SYSTEM TESTING

DTC B1925 Driver Seat Cushion Temperature Sensor
1. Ignition OFF, disconnect the (C2, C5) harness connectors at the memory seat module.
2. Test for infinite resistance between the driver seat cushion temperature sensor signal circuit terminal 1 (C5) and ground.
- If less than infinite resistance, test the signal circuit for a short to ground.
3. Test for 3.0K-300K ohms of resistance between the signal circuit terminal 1 (C5) and the low reference circuit terminal 3 (C2).
- If greater than 300K ohms, test the signal circuit and low reference circuit for a short to voltage or an open/high resistance. If the circuits test normal, replace the seat cushion temperature sensor.
- If less than 3.0K ohms, test for a short between the signal and low reference circuits. If the circuits test normal, replace the seat cushion temperature sensor.
4. If all circuits test normal, replace the memory seat module.

DTC B2170 Passenger Seat Cushion Temperature Sensor
1. Ignition OFF, disconnect the (C2, C5) harness connectors at the memory seat module.
2. Test for infinite resistance between the passenger seat cushion temperature sensor signal circuit terminal 2 (C5) and ground.
- If less than infinite resistance, test the signal circuit for a short to ground.
3. Test for 3.0K-300K ohms of resistance between the signal circuit terminal 2 (C5) and the low reference circuit terminal 6 (C2).
- If greater than 300K ohms, test the signal circuit and low reference circuit for a short to voltage or an open/high resistance. If the circuits test normal, replace the seat cushion temperature sensor.
- If less than 3.0K ohms, test for a short between the signal and low reference circuits. If the circuits test normal, replace the seat cushion temperature sensor.
4. If all circuits test normal, replace the memory seat module.

REPAIR INSTRUCTIONS
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
- Seat Cushion Heater Element Replacement - Front
- Control Module References for the memory seat module replacement, setup, and programming. Programming and Relearning