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 B1935 04: Left Seat Back Heater Circuit OpenDTC B1935 0A: Left Seat Back Heater Circuit Rate of Change Below Threshold
DTC B1935 0B: Left Seat Back Heater Circuit Current Above Threshold
DTC B1935 0C: Left Seat Back Heater Circuit Current Below Threshold
DTC B1935 0D: Left Seat Back Heater Circuit Resistance Above Threshold
DTC B1935 0E: Left Seat Back Heater Circuit Resistance Below Threshold
DTC B1935 1F: Left Seat Back Heater Circuit Intermittent
DTC B2180 04: Right Seat Back Heater Circuit Open
DTC B2180 0A: Right Seat Back Heater Circuit Rate of Change Below Threshold
DTC B2180 0B: Right Seat Back Heater Circuit Current Above Threshold
DTC B2180 0C: Right Seat Back Heater Circuit Current Below Threshold
DTC B2180 0D: Right Seat Back Heater Circuit Resistance Above Threshold
DTC B2180 0E: Right Seat Back Heater Circuit Resistance Below Threshold
DTC B2180 1F: Right Seat Back Heater Circuit Intermittent
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Left rear heated seat back element supply voltage | B2508 02 | B1935 0C, B1935 0D | B2345 00, B2508 01 | B1935 0B, B1935 0E |
Left rear heated seat back element control | B2345 00, B2508 02 | B1935 0C, B1935 0D | B2345 00, B2508 01 | B1935 0B, B1935 0E |
Left rear heated seat back temperature sensor signal | B2435 02 | B1935 04, B1935 1F, B2435 0D | B1935 04, B1935 1F, B2435 0D | B1935 0A, B2345 13, B2345 42, B2345 4B |
Left rear heated seat back temperature sensor low reference | -- | B1935 04, B1935 1F, B2435 0D | -- | B2345 13, B2345 42, B2345 4B |
Left rear heated seat cushion element supply voltage | B2508 02 | B2425 0C, B2425 0D | B2345 00, B2508 01 | B2425 0B, B2425 0E |
Left rear heated seat cushion element control | B2345 00, B2508 02 | B2425 0C, B2425 0D | B2345 00, B2508 01 | B2425 0B, B2425 0E |
Left rear heated seat cushion temperature sensor signal | B1925 02, B2425 1F | B1925 05, B2425 04, B2425 1F | B1925 05, B2425 04, B2425 1F | B2345 13, B2345 42, B2345 4B, B2425 0A |
Left rear heated seat cushion temperature sensor low reference | -- | B1925 05, B2425 04, B2425 1F | -- | B2345 13, B2345 42, B2345 4B |
Right rear heated seat back element supply voltage | B2508 02 | B2180 0C, B2180 0D | B2345 00, B2508 01 | B2180 0B, B2180 0E |
Right rear heated seat back element control | B2345 00, B2508 02 | B2180 0C, B2180 0D | B2345 00, B2508 01 | B2180 0B, B2180 0E |
Right rear heated seat back temperature sensor signal | B2440 02 | B2180 04, B2180 1F, B2440 05 | B2180 04, B2180 1F, B2440 05 | B2180 0A, B2345 13, B2345 42, B2345 4B |
Right rear heated seat back temperature sensor low reference | -- | B2180 04, B2180 1F, B2440 05 | -- | B2345 13, B2345 42, B2345 4B |
Right rear heated seat cushion element supply voltage | B2508 02 | B2430 0C, B2430 0D | B2345 00, B2508 01 | B2430 0B, B2430 0E |
Right rear heated seat cushion element control | B2345 00, B2508 02 | B2430 0C, B2430 0D | B2345 00, B2508 01 | B2430 0B, B2430 0E |
Right rear heated seat cushion temperature sensor signal | B2170 02, B2430 1F | B2430 04, B2430 1F, B2170 05 | B2430 04, B2430 1F, B2170 05 | B2345 13, B2345 42, B2345 4B, B2430 0A |
Right rear heated seat cushion temperature sensor low reference | -- | B2430 04, B2430 1F, B2170 05 | -- | B2345 13, B2345 42, B2345 4B |
Circuit/System Description
The left and right rear passenger heated seats are controlled by the rear heated seat module (RHSM) . When active, power is applied to the seat cushion and back heater elements through a common voltage supply circuit. Each individual heater element is grounded by the RHSM through separate low side drive control circuits. The heater element control circuits are pulse width modulated to ground by the module in order to control the seat temperatures by regulating the current flow through the heater elements. The module then monitors the current flow through the heating elements and the of rate change of the temperature sensor to verify correct heated seat operation.
Conditions for Running the DTC
The heated seat system must be active.
Conditions for Setting the DTC
B1935 04, B2180 04
The module does not detect a temperature change within 210 seconds.
B1935 0A, B2180 0A
The module detects that the set point temperature has not been reached within 8.5 minutes.
B1935 0B, B1935 0E, B2180 0B, B2180 0E
By measuring the current and voltage output to the seat back heating element, the rear heated seat module calculates that the heating element resistance is below the minimum resistance value of 4.3 ohms.
B1935 0C, B1935 0D, B2180 0C, B2180 0D
By measuring the current and voltage output to the seat back heating element, the rear heated seat module calculates that the heating element resistance is above the maximum resistance value of 10.4 ohms.
B1935 1F, B2180 1F
The temperature sensor voltage is erratic or sudden change.
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 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. |
Reference Information
Schematic Reference
Connector End View Reference
Power Seat Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
B1935 0A, B1935 0B, B1935 0C, B1935 0D, B1935 0E, B1935 04, or B1935 1F
- Ignition OFF, disconnect the C1 harness connector at the RHSM.
- Test for less than 10.4 ohms between the supply voltage circuit terminal 3 and the control circuit terminal 1.
- Ignition OFF, disconnect the C2, C4 harness connectors at the RHSM.
- Test for 1.4K-300K ohms between the signal circuit terminal 19 C4 and the low reference circuit terminal 5 C2.
- Ignition OFF, connect the C1, C2, C4 harness connectors at the RHSM.
- Disconnect the harness connector at the seat back heating element/temperature sensor.
- Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal C and ground.
- If all circuits test normal, replace the RHSM.
| ⇒ | If greater than the specified range, test the supply voltage circuit and the control circuit for an open/high resistance. If the circuits test normal, replace the seat back 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 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. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the RHSM. |
| ⇒ | If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the RHSM. |
B2180 0A, B2180 0B, B2180 0C, B2180 0D, B2180 0E, B2180 04, or B2180 1F
- Ignition OFF, disconnect the C1 harness connector at the RHSM.
- Test for less than 10.4 ohms between the supply voltage circuit terminal 6 and the control circuit terminal 4.
- Ignition OFF, disconnect the C2, C4 harness connector at the RHSM.
- Test for 1.4K-300K ohms between the signal circuit terminal 10 C4 and the low reference circuit terminal 7 C2.
- Ignition OFF, connect the C1, C2, C4 harness connectors at the RHSM.
- Disconnect the harness connector at the seat back heating element/temperature sensor.
- Ignition ON, test for 4.8-5.2 volts between the signal circuit terminal C and ground.
- If all circuits test normal, replace the RHSM.
| ⇒ | If greater than the specified range, test the supply voltage circuit and the control circuit for an open/high resistance. If the circuits test normal, replace the seat back 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 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. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the RHSM. |
| ⇒ | If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the RHSM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for RHSM replacement, setup, and programming |
