Front Seat
DTC B1925 or B2170 (Front Seat)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
The heated seat temperature sensor that set this (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 MSM will 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 MSM 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 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.
Reference Information
Schematic Reference
Heated/Cooled Seat Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Heated Seats Description and Operation (KA1) (Heated Seats Description and Operation (KA1))Heated Seats Description and Operation (KA6) (Heated Seats Description and Operation (KA6))
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
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Testing
B1925 02 or B1925 05
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 the 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 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 ground. If the circuit tests normal, replace the MSM.
6. If all circuits test normal, replace the MSM.
B2170 02 or B2170 05
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 the 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 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 ground. If the circuit tests normal, replace the MSM.
6. If all circuits test normal, replace the MSM.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Driver or Passenger Seat Cushion Heater Replacement (Driver or Passenger Seat Cushion Heater Replacement)
* Control Module References (Programming and Relearning) for the MSM replacement, setup, and programming