PRE-RELEASE
Front Heated Seat Malfunction (With Memory)
| Front Heated Seat Malfunction (With Memory) |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| Diagnostic Fault Information |
| Circuit | Short to Ground | Open/High Resistance | Short to Voltage | 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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-
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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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-
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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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-
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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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-
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1. Power seats inoperative
2. Heated seats inoperative |
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| Circuit/System Description |
The driver and passenger heated seats are controlled by separate heated seat switches located in the HVAC control. When a heated seat switch is pressed, a serial data message is sent from the HVAC control to the HVAC control module. The HVAC control module serves as a gateway to transmit the message to the seat memory control module via the serial data line indicating the heated seat command. In response to this message, the seat memory control module then 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 HVAC control to either illuminate or turn off the appropriate temperature indicator.
| Reference Information |
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
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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Scan Tool Reference
Control Module References for scan tool information
| Circuit/System Testing |
| 1. |
Ignition OFF, disconnect the X4 harness connector at the K40 seat memory control module.
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| 2. |
Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 5 and ground.
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| 3. |
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. |
Ignition OFF, connect the X4 harness connector at the K40 seat memory control module.
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| 5. |
Engine ON, observe the scan tool Driver Seat Heating/Venting/Cooling Mode parameter while pressing the driver HEATED seat switch. The reading should change between Off and Back & Cushion Heat.
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| 6. |
If not the specified value, replace the A26 HVAC control.
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| 7. |
Observe the scan tool Passenger Seat Heating/Venting/Cooling Mode parameter while pressing the passenger HEATED seat switch. The reading should change between Off and Back & Cushion Heat.
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| 8. |
If not the specified value, replace the A26 HVAC control.
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| 9. |
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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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Heater and Air Conditioning Control Replacement
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Control Module References
for seat memory control module replacement, setup, and programming
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