B1925
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 Cushion Heater Sensor Circuit Shorted to Ground
DTC B2170 02
- Right Seat Cushion Heater Sensor Circuit Shorted to Ground
Diagnostic Fault Information
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 heated seat module supplies a 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 circuit 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 heated seat module is active, and none of the power diagnostic DTCs are current.
Conditions for Setting the DTC
B1925, B2170 02
The temperature sensor voltage drops below 0.8 volts for more than 1 second
B1925, B2170 05
The temperature sensor voltage exceeds 5 volts 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 3 seconds after the reference voltage returns to normal operating range.
* The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.
Circuit/System Testing
B1925 Left Seat Cushion Sensor
1. Ignition OFF, disconnect the C2 and C4 harness connectors at the heated seat module.
2. Test for infinite resistance between the sensor signal circuit C4 terminal 9 and ground.
• If less than infinite resistance, test the signal circuit for a short to ground.
Important: If the resistance is measured with the seat still warm, the resistance may vary within the specified range depending on the temperature of the seat.
3. Test for 250-300K ohms of resistance between the temperature sensor signal circuit C4 terminal 9 and the low reference circuit C2 terminal 6.
• 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 temperature sensor.
• If less than 250 ohms, replace the seat temperature sensor.
4. If all circuits test normal, replace the heated seat module.
B2170 Right Seat Cushion Sensor
1. Ignition OFF, disconnect the C2 and C4 harness connectors at the heated seat module.
2. Test for infinite resistance between the temperature sensor signal circuit C4 terminal 20 and ground.
• If less than infinite resistance, test the signal circuit for a short to ground.
Important: If the resistance is measured with the seat still warm, the resistance may vary within the specified range depending on the temperature of the seat.
3. Test for 250-300K ohms of resistance between the temperature sensor signal circuit C4 terminal 20 and the low reference circuit C2 terminal 8.
• 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 temperature sensor.
• If less than 250 ohms, replace the seat temperature sensor.
4. If all circuits test normal, replace the heated seat module.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
* Seat Cushion Heater Element Replacement - Front (Impala) Seat Cushion Heater Element Replacement - Front (Monte Carlo)
* Programming and Relearning Programming and Relearning