• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Driver Heated Seat Element Supply Voltage | B2508 02 | B2425 0C, B2425 0D | B2508 01 | -- |
Driver Heated Seat Element Control | B2508 02 | B2425 0C, B2425 0D | B2508 01 | -- |
Driver Heated Seat Temperature Sensor Signal | B1925 02 | B1925 05, B2425 04, B2425 1F | B1925 05, B2425 04, B2425 1F | B2345 13, B2345 42, B2345 4B |
Driver Heated Seat Temperature Sensor Low Reference | -- | B1925 05, B2425 04, B2425 1F | -- | B2345 13, B2345 42, B2345 4B |
Passenger Heated Seat Element Supply Voltage | B2508 02 | B2430 0C, B2430 0D | B2508 01 | -- |
Passenger Heated Seat Element Control | B2508 02 | B2430 0C, B2430 0D | B2508 01 | -- |
Passenger Heated Seat Temperature Sensor Signal | B2170 02 | B2170 05, B2430 04, B2430 1F | B2170 05, B2430 04, B2430 1F | B2345 13, B2345 42, B2345 4B |
Passenger Heated Seat Temperature Sensor Low Reference | -- | B2170 05, B2430 04, B2430 1F | -- | B2345 13, B2345 42, B2345 4B |
Both, the driver and passenger heated seats are controlled by the heated seat module (HSM) that is located under the driver seat cushion. When the heated seat is active, the HSM applies power through a common voltage supply circuit to the seat heater elements. The HSM controls the seat temperature by providing a pulse width modulation (PWM) ground through the seat heater element control circuit to the heater elements. The HSM then monitors the current flow through the heating elements and the rate of change of the temperature sensor to verify correct heated seat operation.
The HSM must be powered and the heated seat must be enabled.
The HSM does not detect a temperature change for up to 210 seconds.
The HSM detects that the set point temperature has not been reached for up to 8.5 minutes.
By measuring current and voltage output to the seat heating elements every 10 seconds, the HSM calculates that the heating element resistance is below the minimum resistance.
By measuring current and voltage output to the seat heating elements every 10 seconds, the HSM calculates that the heating element resistance is above the maximum resistance.
The temperature sensor voltage is erratic or changes suddenly.
The heated seat function for the affected seat will be disabled.
• | The current DTC clears when the malfunction is no longer present, 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. |
Heated Seats Description and Operation
Control Module References for scan tool information
Important: When measuring the resistance, all of the resistance values below are based on the seat being at room temperature of 20°C (68°F).
⇒ | If not within the specified range, replace the seat back heating element. |
⇒ | If greater than the specified range, test the control circuits for an open/high resistance. If the circuits test normal, replace the seat cushion heating element. |
⇒ | If less than the specified range, test for a short between the control circuits. If the circuits test normal, replace the 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 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 HSM. |
⇒ | If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the HSM. |
Important: When measuring the resistance, all of the resistance values below are based on the seat being at room temperature of 20°C (68°F).
⇒ | If not within the specified range, replace the seat back heating element. |
⇒ | If greater than the specified range, test the control circuits for an open/high resistance. If the circuits test normal, replace the seat cushion heating element. |
⇒ | If less than the specified range, test for a short between the control circuits. If the circuits test normal, replace the 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 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 HSM. |
⇒ | If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the HSM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for HSM replacement, setup, and programming |