Front Heated Seat Malfunction (With Memory A45)
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Front Heated Seat Malfunction (With Memory A45)
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Diagnostic Fault Information
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Circuit
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Short to Ground
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Open/High Resistance
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Short to Voltage
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Signal Performance
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Seat Memory Control Module B+ Terminal 5 X4
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B242A 02, B2425 0D, B2430 0D, 1, 2
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B242A 02, B2425 0D, B2430 0D, 1, 2
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-
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-
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Driver Heated Seat Element Control Terminal 11 X3
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B242A 02
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B2425 0D
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B242A 01
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B2425 0B, B2425 0E
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Driver Heated Seat Element Control Terminal 6 X3
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B242A 02
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B2425 0D
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B242A 01
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B2425 0B, B2425 0E
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Driver Heated Seat Temperature Sensor Signal
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B1925 02
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B1925 05
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B1925 05
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B2345 13
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Driver Heated Seat Temperature Sensor Low Reference
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-
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B1925 05
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-
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B2345 13
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Passenger Heated Seat Element Control Terminal 10 X3
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B242A 02
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B2430 0D
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B242A 01
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B2430 0B, B2430 0E
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Passenger Heated Seat Element Control Terminal 4 X3
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B242A 02
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B2430 0D
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B242A 01
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B2430 0B, B2430 0E
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Passenger Heated Seat Temperature Sensor Signal
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B2170 02
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B2170 05
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B2170 05
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B2345 13
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Passenger Heated Seat Temperature Sensor Low Reference
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-
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B2170 05
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-
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B2345 13
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1. Power seats inoperative
2. Heated seats inoperative
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Circuit/System Description
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The driver and front passenger heated seats are controlled by separate heated seat switches that are located together with the radio/HVAC control. When a heated seat switch is pressed, a serial data message is sent from the radio/HVAC controls to the HVAC control module indicating the heated seat command. The HVAC control module serves as a gateway to transmit the message to the seat memory control module via the serial data line. In response to this message, the seat memory control module applies battery voltage through the element supply voltage circuit to the appropriate seat heating elements. The seat memory control module then sends a serial data message back to the HVAC control module to gateway the information to the radio/HVAC controls to either illuminate or turn off the appropriate temperature indicator.
Schematic Reference
Heated/Cooled Seat Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Heated/Vented Seat Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References
for scan tool information
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1.
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Ignition OFF, disconnect the X4 harness connector at the K40 seat memory control module.
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2.
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Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 5 and ground.
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3.
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If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
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4.
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Ignition OFF, connect the X4 harness connector at the K40 seat memory control module.
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5.
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Engine ON, observe the scan tool Driver Seat Heating/Venting/Cooling Mode parameter while pressing the driver seat HEAT switch. The reading should change between Off and Back & Cushion.
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6.
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If not the specified value, replace the A20 radio/HVAC control.
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7.
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Check the scan tool Passenger Seat Heating/Venting/Cooling Mode parameter while pressing the passenger seat HEAT switch. The reading should change between Off and Back & Cushion.
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8.
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If not the specified value, replace the A20 radio/HVAC control.
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9.
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If the scan tool parameter readings test normal, there are no DTCs set, and the driver and/or passenger heated seat is inoperative, replace the K40 seat memory control module.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
