B2180

DTC B1935 or B2180

DTC DESCRIPTORS

DTC B1935 04: Left Seat Back Heater Circuit Open

DTC 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 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 1F: Right Seat Back Heater Circuit Intermittent

DIAGNOSTIC FAULT INFORMATION




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

CIRCUIT/SYSTEM DESCRIPTION
The left and right front passenger heated seats are controlled by the memory seat module. 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 memory seat module 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 memory seat module is powered and the heated seat must be enabled.

CONDITIONS FOR SETTING THE DTC
The heated seat system must be active.

B1935/B2180 04
The module does not detect a temperature change for up to 210 seconds.

B1935/B2180 0A
The module detects that the set point temperature has not been reached for up to 8.5 minutes.

B1935/B2180 0B
By measuring the current and voltage output to the seat back heating element every 10 seconds, the memory seat module calculates that the heating element resistance is below the minimum resistance value of 2.4 ohms.

B1935/B2180 0C
By measuring the current and voltage output to the seat back heating element every 10 seconds, the memory seat module calculates that the heating element resistance is above the maximum resistance value of 10 ohms.

B1935/B2180 1F
The temperature sensor voltage is erratic or changes suddenly.

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 will the set code to history, 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.

CIRCUIT/SYSTEM TESTING

B1935 Driver Seat Back
1. Ignition OFF, disconnect the (C1) harness connector at the memory seat module.
2. Test for less than 10 ohms of resistance between the seat back heater element supply voltage circuit terminal 14 and the control circuit terminal 1.
- If greater than 10 ohms, 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.
3. Ignition OFF, disconnect the (C2, C5) harness connectors at the memory seat module.
4. Test for 2.4K-300K ohms of resistance between the seat back temperature sensor signal circuit terminal 4 (C5) and the low reference circuit terminal 2 (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 2.4K ohms, test for a short between the signal and low reference circuits. If the circuits test normal, replace the seat back temperature sensor.
5. Ignition OFF, connect the (C1, C2, C5) harness connectors at the memory seat module.
6. Disconnect the harness connector at the seat back heating element/temperature sensor.
7. Ignition ON, test for less than 5.2 volts between the temperature sensor signal circuit terminal C and ground.
- If greater than 5.2 volts, test the signal circuit for a short to voltage. If the circuit tests normal, replace the memory seat module.
8. If all circuits test normal, replace the memory seat module.

B2180 Passenger Seat Back
1. Ignition OFF, disconnect the (C1) harness connector at the memory seat module.
2. Test for less than 10 ohms of resistance between the seat back heater element supply voltage circuit terminal 6 and the control circuit terminal 4.
- If greater than 10 ohms, 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.
3. Ignition OFF, disconnect the (C2, C5) harness connectors at the memory seat module.
4. Test for 2.4K-300K ohms of resistance between the seat back temperature sensor signal circuit terminal 3 (C5) 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 2.4K ohms, test for a short between the signal and low reference circuits. If the circuits test normal, replace the seat back temperature sensor.
5. Ignition OFF, connect the (C1, C2, C5) harness connectors at the memory seat module.
6. Disconnect the harness connector at the seat back heating element/temperature sensor.
7. Ignition ON, test for less than 5.2 volts between the temperature sensor signal circuit terminal C and ground.
- If greater than 5.2 volts, test the signal circuit for a short to voltage. If the circuit tests normal, replace the memory seat module.
8. If all circuits test normal, replace the memory seat module.

REPAIR INSTRUCTIONS
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
- Seat Back Heater Element Replacement - Front
- Control Module References for the memory seat module replacement, setup, and programming. Programming and Relearning