B2435

DTC B2435 or B2440

DTC Descriptors

DTC B2435 02
- Left Seat Back Heater Sensor Circuit Shorted to Ground

DTC B2440 02
- Right Seat Back Heater Sensor Circuit Shorted to Ground

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview









Circuit/System Description

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

Conditions for Setting the DTC

B2435/B2440 02

The temperature sensor voltage drops below 0.80 volt 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.

Circuit/System Testing

B2435 Left Rear Seat Back
1. Ignition OFF, disconnect the (C2, C4) harness connectors at the rear heated seat module.
2. Test for infinite resistance between the seat back temperature sensor signal circuit terminal 19 and ground.

• If less than infinite resistance, test the signal circuit for a short to ground.

3. Test for 2.0K-300K ohms of resistance between the seat back temperature sensor signal circuit terminal 19 (C4) and the low reference circuit terminal 5 (C2).

• 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 back temperature sensor.
• If less than 2.0K ohms, test for a short between the signal and low reference circuits. If the circuits test normal, replace the seat back temperature sensor.

4. If all circuits test normal, replace the rear heated seat module.

B2440 Right Rear Seat Back
1. Ignition OFF, disconnect the (C2, C4) harness connectors at the rear heated seat module.
2. Test for infinite resistance between the seat back temperature sensor signal circuit terminal 10 (C4) and ground.

• If less than infinite resistance, test the signal circuit for a short to ground.

3. Test for 2.0-300K ohms of resistance between the seat back temperature sensor signal circuit terminal 10 (C4) and the low reference circuit terminal 7 (C2).

• 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 back temperature sensor.
• If less than 2.0 ohms, test for a short between the signal and low reference circuits. If the circuits test normal, replace the seat back temperature sensor.

4. If all circuits test normal, replace the rear heated seat module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Seat Back Heater Replacement - Rear
* Programming and Relearning for the rear heated seat module programming and setup. Programming and Relearning