Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | 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 Sensor Circuit Short to GroundDTC B1925 05: Left Seat Heater Sensor Circuit Short to Battery or Open
DTC B2170 02: Right Seat Heater Cushion Sensor Circuit Short to Ground
DTC B2170 05: Right Seat Heater Cushion Sensor Circuit Short to Battery or Open
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
B+ MSM Terminal 5 X3 | 1, 2, B2425 0D, B2430 0D | 1, 2, B2425 0D, B2430 0D | -- | -- |
Driver Heated Seat Element Supply Voltage | B2508 02 | B2425 0D | B2508 01 | B2425 0E |
Driver Heated Seat Element Control | B2508 02 | B2425 0D | B2508 01 | B2425 0E |
Driver Heated Seat Temperature Sensor Signal | B1925 02 | B1925 05 | B1925 05 | B2345 13, B2345 42, B2345 4B |
Driver Heated Seat Temperature Sensor Low Reference | -- | B1925 05 | -- | B2345 13, B2345 42, B2345 4B |
Passenger Heated Seat Element Supply Voltage | B2508 02 | B2430 0D | B2508 01 | B2430 0E |
Passenger Heated Seat Element Control | B2508 02 | B2430 0D | B2508 01 | B2430 0E |
Passenger Heated Seat Temperature Sensor Signal | B2170 02 | B2170 05 | B2170 05 | B2345 13, B2345 42, B2345 4B |
Passenger Heated Seat Temperature Sensor Low Reference | -- | B2170 05 | -- | B2345 13, B2345 42, B2345 4B |
1. Power seats inoperative 2. Heated seats inoperative | ||||
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 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 sensor.
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 0.8 volt for more than 1 second.
B1925 02, 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 the code to history 3 seconds after the reference voltage returns to 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. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Heated/Vented Seat Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
B1925 02 or B1925 05
- Ignition OFF, disconnect the X2, X5 harness connectors at the MSM.
- Test for 1.4K-300K ohms between the signal circuit terminal 1 X5 and the low reference circuit terminal 3 X2.
- Ignition OFF, connect the X2, X5 harness connectors at the MSM.
- Disconnect the harness connector at the seat cushion heating element/temperature sensor.
- Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal C and ground.
- If all circuits test normal, replace the MSM.
Important: When measuring the resistance, the resistance values are based on the seat being at room temperature of 20°C (68°F).
| ⇒ | 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 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 temperature sensor. |
| ⇒ | 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. |
B2170 02 or B2170 05
- Ignition OFF, disconnect the X2, X5 harness connectors at the MSM.
- Test for 1.4K-300K ohms between the signal circuit terminal 2 X5 and the low reference circuit terminal 6 X2.
- Ignition OFF, connect the X2, X5 harness connectors at the MSM.
- Disconnect the harness connector at the seat cushion heating element/temperature sensor.
- Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal C and ground.
- If all circuits test normal, replace the MSM.
Important: When measuring the resistance, the resistance values are based on the seat being at room temperature of 20°C (68°F).
| ⇒ | 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 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 temperature sensor. |
| ⇒ | 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. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for MSM replacement, setup, and programming |
