Diagnostic Instructions

DTC Descriptors

DTC B2435 02: Left Seat Back Heater Sensor Circuit Short to Ground

DTC B2435 05: Left Seat Back Heater Sensor Circuit Short to Battery or Open

DTC B2440 02: Right Seat Back Heater Sensor Circuit Short to Ground

DTC B2440 05: Right Seat Back Heater Sensor Circuit Short to Battery or Open

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Driver Heated Seat Back Element Supply Voltage	B2508 02	B1935 0D	B2508 01	B1935 0E
Driver Heated Seat Back Element Control	B2508 02	B1935 0D	B2508 01	B1935 0E
Driver Heated Seat Back Temperature Sensor Signal	B2435 02	B2435 05	B2435 05	B2345 13, B2345 42, B2345 4B
Driver Heated Seat Back Temperature Sensor Low Reference	--	B2435 05	--	B2345 13, B2345 42, B2345 4B
Driver Heated Seat Cushion Element Supply Voltage	B2508 02	B2425 0D	B2508 01	B2425 0E
Driver Heated Seat Cushion Element Control	B2508 02	B2425 0D	B2508 01	B2425 0E
Driver Heated Seat Cushion Temperature Sensor Signal	B1925 02	B1925 05	B1925 05	B2345 13, B2345 42, B2345 4B
Driver Heated Seat Cushion Temperature Sensor Low Reference	--	B1925 05	--	B2345 13, B2345 42, B2345 4B
Passenger Heated Seat Back Element Supply Voltage	B2508 02	B2180 0D	B2508 01	B2180 0E
Passenger Heated Seat Back Element Control	B2508 02	B2180 0D	B2508 01	B2180 0E
Passenger Heated Seat Back Temperature Sensor Signal	B2440 02	B2440 05	B2440 05	B2345 13, B2345 42, B2345 4B
Passenger Heated Seat Back Temperature Sensor Low Reference	--	B2440 05	--	B2345 13, B2345 42, B2345 4B
Passenger Heated Seat Cushion Element Supply Voltage	B2508 02	B2430 0D	B2508 01	B2430 0E
Passenger Heated Seat Cushion Element Control	B2508 02	B2430 0D	B2508 01	B2430 0E
Passenger Heated Seat Cushion Temperature Sensor Signal	B2170 02	B2170 05	B2170 05	B2345 13, B2345 42, B2345 4B
Passenger Heated Seat Cushion Temperature Sensor Low Reference	--	B2170 05	--	B2345 13, B2345 42, B2345 4B

Circuit/System Description

The heated seat temperature sensor that set this diagnostic trouble code (DTC) is located in seat back 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 circuits 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 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 heated seat system must be active.

Conditions for Setting the DTC

B2435 02, B2440 02

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

B2435 05, B2440 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

Reference Information

Schematic Reference

Heated/Cooled Seat Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Heated Seats Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

B2435 02 or B2435 05

1. Ignition OFF, disconnect the X2, X5 harness connectors at the MSM.
2. Test for 1.7K-300K ohms between the signal circuit terminal 4 X5 and the low reference circuit terminal 2 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 back 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 back temperature sensor.

3. Ignition OFF, connect the X2, X5 harness connectors to the MSM.
4. Disconnect the harness connector at the seat back 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 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.

B2440 02 or B2440 05

1. Ignition OFF, disconnect the X2, X5 harness connectors at the MSM.
2. Test for 1.7K-300K ohms between the signal circuit terminal 3 X5 and the low reference circuit terminal 5 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 back 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 back temperature sensor.

3. Ignition OFF, connect the X2, X5 harness connectors to the MSM.
4. Disconnect the harness connector at the seat back 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 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 after completing the diagnostic procedure.