DTC B242A (With Memory A45)
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DTC B242A (With Memory A45)
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DTC B242A 01
Seat Heaters Common Circuit Short to Battery
DTC B242A 02
Seat Heaters Common Circuit Short to Ground
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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 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 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 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 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 seat memory control module controls seat heating operation for both the driver and front passenger seats. The heating elements are controlled through individual high side and low side control circuits. The low side control circuits for both seats are connected to a common reference point internal to the module. This reference point is biased to approximately 2.5 V. Before the seat memory control module will allow heated seat operation, it checks to see if this biased voltage is shorted to ground or voltage. Once the module verifies that it is not closing to a shorted heating element, it allows for heated seat operation. The module will then continue to monitor the heating elements for a shorted circuit.
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Conditions for Running the DTC
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•
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DTC B1325 must not be present.
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•
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The seat memory control module must be powered.
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Conditions for Setting the DTC
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B242A 01
The seat memory control module detects a short to voltage on the heater element control circuits.
B242A 02
The seat memory control module detects a short to ground on the heater element control circuits.
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Action Taken When the DTC Sets
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The heated seat function for both seats will be disabled.
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Conditions for Clearing the DTC
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•
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The current DTC will clear and set a history code 3 seconds after the reference voltage returns to normal operating range and the ignition is cycled OFF then back to ACC or RUN.
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•
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The history DTC will clear after 40 consecutive fault-free ignition cycles have occurred.
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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 and disconnect the X3 harness connector at the K40 seat memory control module.
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5.
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Test for infinite resistance between the control circuit terminal 11 and ground.
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6.
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If not the specified value, test the control circuit for a short to ground.
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7.
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Test for infinite resistance between the control circuit terminal 10 and ground.
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8.
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If not the specified value, test the control circuit for a short to ground.
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9.
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Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 11 and ground.
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10.
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If the test lamp illuminates, test the control circuit for a short to voltage.
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11.
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Verify that a test lamp does not illuminate between the control circuit terminal 10 and ground.
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12.
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If the test lamp illuminates, test the control circuit for a short to voltage.
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13.
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If all circuits test normal, replace the K40 seat memory control module.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Control Module References
for seat memory control module replacement, setup, and programming
