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: Driver Seat Heater Sensor CircuitDTC B2170: Front Passenger Seat Heater Sensor Circuit
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Heated Seat Relay B+ | 1, B1920, B2165 | 1, B1920, B2165 | -- | -- |
Heated Seat Relay Control | 1, B2508, B2509 | B2508, B2509 | B2508, B2509 | -- |
Heated Seat Relay Ground | -- | B2508, B2509 | -- | -- |
Heated Seat Cushion Temperature Sensor Signal | B1925, B2170 | B1920, B2165 | B1920, B1925, B2165, B2170 | -- |
Heated Seat Cushion Temperature Sensor Low Reference | -- | 1, B1920, B2165 | -- | -- |
Heated Seat Heater Element Control | 1, B1920, B2165 | 1, B1920, B2165 | -- | -- |
Heated Seat Element Ground | -- | 1, B1920, B2165 | -- | -- |
1. Front heated seat malfunction | ||||
Circuit/System Description
The heated seat temperature sensor is located in the seat cushion just under the seat cover within the seat heating element. The body control module (BCM) supplies the heated seat temperature sensor with a temperature sensor signal circuit and a temperature sensor low reference circuit. The BCM monitors the voltage of the heated seat temperature sensor signal circuit to determine the temperature of the seat. The BCM cycles the heated seat relay on and off in order to maintain the desired seat temperature based on the voltage feedback from the temperature sensor.
The BCM also monitors the sensor signal circuit for a change in voltage that is either to fast or to slow. The slow rate check is performed only when the heated seat is initially turned on with a cold seat in order to prevent setting a false DTC.
Conditions for Running the DTC
| • | DTC B1327 must not be present. |
| • | Battery voltage must be between 9-16 V. |
Conditions for Setting the DTC
B1925
The DTC will set when the BCM detects a short to ground or voltage in the driver temperature sensor signal circuit.
B2170
The DTC will set when the BCM detects a short to ground or voltage in the passenger temperature sensor signal circuit.
Actions Taken When the DTC Sets
The heated seat system 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. |
| • | The condition responsible for setting the DTC no longer exists. |
| • | A history DTC will clear once 50 consecutive fault-free ignition cycles have occurred. |
Diagnostic Aids
When DTC B1925 or B2170 are set as current, the BCM disables the heated seat function not allowing any heated seat relay control functions to occur. Cycling the ignition OFF then ON will reset the DTC and allow relay commands.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Heated Seats Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the appropriate seat cushion heater element.
- Test for less than 5.0 Ω between the low reference circuit terminal C and ground.
- Ignition ON, test for 9.8 - 10.2 V between the signal circuit terminal B and ground.
- If all circuits test normal, test or replace the seat cushion heater element.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the BCM. |
| ⇒ | 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 BCM. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM. |
Component Testing
Seat Heater Elements
- Ignition OFF, disconnect the harness connector at the seat cushion heater element.
- Test for 1-5 Ω between terminal A and terminal D.
- Test for 535-168K Ω between terminal B and terminal C.
- Disconnect the harness connector at the seat back heater element.
- Test for 1-5 Ω between terminal A and terminal B.
| ⇒ | If not within the specified range, replace the seat cushion heater element. |
| ⇒ | If not within the specified range, replace the seat cushion heater element. |
| ⇒ | If not within the specified range, replace the seat back heater element. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
