B2170
DTC B1925 or B2170
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptors
DTC B1925 02
- Left Seat Cushion Heater Sensor Circuit Shorted to Ground
DTC B1925 05
- Left Seat Cushion Heater Sensor Circuit Shorted to Battery or Open
DTC B2170 02
- Right Seat Cushion Heater Sensor Circuit Shorted to Ground
DTC B2170 05
- Right Seat Cushion Heater Sensor Circuit Shorted to Battery or Open
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 rear heated seat module 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 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 must be powered.
Conditions for Setting the DTC
B1925 02, B2170 02
The temperature sensor voltage drops below 0.8 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 function for the affected seat will be disabled.
Conditions for Clearing the DTC
* The current DTC will clear and set to history 3 seconds after the reference voltage returns to the normal operating range and the power mode changes to OFF then back to ACC or RUN.
* The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.
Reference Information
Schematic Reference
Heated/Cooled Seat Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Rear Heated Seats Description and Operation (Rear Heated Seats Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Programming and Relearning (Programming and Relearning) for Scan Tool Information
Circuit/System Testing
B1925 Left Rear Seat Cushion Sensor
1. Ignition OFF, disconnect the X2, X4 harness connectors at the rear heated seat module.
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.
2. Test for 1.4K-300K ohms between the signal circuit terminal 9 X4 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 circuits test normal, replace the seat cushion temperature sensor.
• If less than the specified range, test for a short between the signal and low reference circuits. If the circuits test normal, replace the seat cushion temperature sensor.
3. Ignition OFF, connect the X2, X4 harness connectors to the rear heated seat module.
4. Disconnect the harness connector at the seat cushion heating element/temperature sensor.
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 rear heated seat module.
• If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the rear heated seat module.
6. If all circuits test normal, replace the rear heated seat module.
B2170 Right Rear Seat Cushion Sensor
1. Ignition OFF, disconnect the X2, X4 harness connectors at the rear heated seat module.
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.
2. Test for 1.4K-300K ohms between the signal circuit terminal 20 X4 and the low reference circuit terminal 8 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 circuits test normal, replace the seat cushion temperature sensor.
• If less than the specified range, test for a short between the signal and low reference circuits. If the circuits test normal, replace the seat cushion temperature sensor.
3. Ignition OFF, connect the X2, X4 harness connectors to the rear heated seat module.
4. Disconnect the harness connector at the seat cushion heating element/temperature sensor.
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 rear heated seat module.
• If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the rear heated seat module.
6. If all circuits test normal, replace the rear heated seat module.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Rear Seat Cushion Heater Replacement (Rear Seat Cushion Heater Replacement)
* Programming and Relearning (Programming and Relearning) for the rear heated seat control module replacement, setup, and programming