For 1990-2009 cars

### 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 Cushion Heater Sensor Circuit Short to Ground
DTC B1925 05: Left Seat Cushion Heater Sensor Circuit High Voltage/Open
DTC B2170 02: Right Seat Cushion Heater Sensor Circuit Short to Ground
DTC B2170 05: Right Seat Cushion Heater Sensor Circuit High Voltage/Open

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Driver Heated Seat Element Control Terminal 3 X2 | B242A 02 | B2425 0D | B242A 01 | B2425 0E
Driver Heated Seat Element Control Terminal 1 X2 | B242A 02 | B2425 0D | B242A 01 | B2425 0E
Driver Heated Seat Cushion Temperature Sensor Signal | B1925 02 | B1925 05 | B1925 05 | B2345 13
Driver Heated Seat Cushion Temperature Sensor Low Reference | -- | B1925 05 | -- | B2345 13
Passenger Heated Seat Element Control Terminal 5 X2 | B242A 02 | B2430 0D | B242A 01 | B2430 0E
Passenger Heated Seat Element Control Terminal 2 X2 | B242A 02 | B2430 0D | B242A 01 | B2430 0E
Passenger Heated Seat Cushion Temperature Sensor Signal | B2170 02 | B2170 05 | B2170 05 | B2345 13
Passenger Heated Seat Cushion Temperature Sensor Low Reference | -- | B2170 05 | -- | B2345 13

### 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 heated seat module supplies a 5 V 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

• | DTC B1325 must not be present.

• | The heated seat module must be powered.

### Conditions for Setting the DTC

#### B1925 02 or B2170 02

The temperature sensor voltage drops below 0.8 V for more than 1 second.

#### B1925 05 or B2170 05

The temperature sensor voltage is greater than 5 V 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 40 consecutive fault-free ignition cycles have occurred.

### 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

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Testing

#### B1925 02 or B1925 05

1. Ignition OFF, disconnect the X2, X3 harness connectors at the K29 heated seat module.

Note: When measuring the resistance, the resistance values are based on the seat being at room temperature of 20°C (68°F).

2. Test for 1.4k - 300 kΩ between the signal circuit terminal 3 X3 and the low reference circuit terminal 13 X2.

⇒ | If less than the specified range, test for a short between the signal and low reference circuits. If the circuits test normal, replace the E14B seat cushion heating element.

⇒ | 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 E14B seat cushion heating element.

3. Ignition OFF, connect the X2, X3 harness connectors at the K29 heated seat module.
4. Disconnect the harness connector at the E14B seat cushion heating element.
5. Ignition ON, test for 4.8 - 5.2 V between the signal circuit terminal 2 and ground.

⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K29 heated seat module.

⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K29 heated seat module.

6. If all circuits test normal, replace the K29 heated seat module.

#### B2170 02 or B2170 05

1. Ignition OFF, disconnect the X2, X3 harness connectors at the K29 heated seat module.

Note: When measuring the resistance, the resistance values are based on the seat being at room temperature of 20°C (68°F).

2. Test for 1.4k - 300 kΩ between the signal circuit terminal 4 X3 and the low reference circuit terminal 14 X2.

⇒ | If less than the specified range, test for a short between the signal and low reference circuits. If the circuits test normal, replace the E14D seat cushion heating element.

⇒ | 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 circuits test normal, replace the E14D seat cushion heating element.

3. Ignition OFF, connect the X2, X3 harness connectors at the K29 heated seat module.
4. Disconnect the harness connector at the E14D seat cushion heating element.
5. Ignition ON, test for 4.8 - 5.2 V between the signal circuit terminal 2 and ground.

⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K29 heated seat module.

⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K29 heated seat module.

6. If all circuits test normal, replace the K29 heated seat module.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Driver Seat Cushion Heater Replacement

• | Passenger Seat Cushion Heater Replacement

• | Control Module References for heated seat module replacement, setup, and programming