B2170

DTC B1925 or B2170

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 Descriptors

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

DTC B1925 05
- Left Seat Heater Cushion Sensor Circuit Shorted to Battery or Open

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

DTC B2170 05
- Right Seat Heater Cushion Sensor Circuit Shorted to Battery or Open

Diagnostic Fault Information






Circuit/System Description

The heated seat temperature sensor is located in the seat cushion just under the seat cover with the seat heating element. The temperature sensor is a 2 wire thermistor and resistance through the sensor varies with temperature. The signal circuit is referenced from 5 volts within the module and the temperature of the seat surface determines the signal circuit voltage. 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 02, B2170 02

The temperature sensor voltage drops below 0.80 volt for more than 1 second.

B1925 05, B2170 05

The temperature sensor voltage is greater than 5 volts for more than 1 second.

Action Taken When the DTC Sets

The heated seat cushion function for the affected seat will be disabled.

Conditions for Clearing the DTC

* The current DTC will clear 3 seconds after the reference voltage returns to normal operating range, 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.

Circuit/System Testing

B1925

1. Ignition OFF, disconnect the X2, X5 harness connectors at the MSM.
2. Test for 850-300k ohms between the signal circuit terminal 1 X5 and the low reference circuit terminal 3 X2.

^ If greater than the specified range, test the signal circuit and low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the seat cushion heater element.
^ If less than the specified range, test for a short between the signal and low reference circuits. If the circuit tests normal, replace the seat cushion heater element.

3. Connect the X2, X5 harness connectors at the MSM.
4. Disconnect the harness connector at the seat cushion heater element.
5. Ignition ON, test for 4.8-5.2 volts between the temperature sensor signal circuit terminal C and ground.

^ If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the MSM.
^ If less than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the MSM.

6. If all circuits test normal, replace the MSM.

B2170

1. Ignition OFF, disconnect the X2, X5 harness connectors at the MSM.
2. Test for 850-300k ohms between the signal circuit terminal 2 X5 and the low reference circuit terminal 6 X2.

^ If greater than the specified range, test the signal circuit and low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the seat cushion heater element.
^ If less than the specified range, test for a short between the signal and low reference circuits. If the circuit tests normal, replace the seat cushion heater element.

3. Connect the X2, X5 harness connectors at the MSM.
4. Disconnect the harness connector at the seat cushion heater element.
5. Ignition ON, test for 4.8-5.2 volts between the temperature sensor signal circuit terminal C and ground.

^ If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the MSM.
^ If less than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the MSM.

6. If all circuits test normal, replace the MSM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Driver Seat and Passenger Seat Cushion Heater Replacement