Possible Causes
PINPOINT TEST AC : DTC B272D
WARNING: Incorrect repair techniques or actions can cause an accidental Supplemental Restraint System (SRS) deployment. Never compromise or depart from these instructions. Failure to precisely follow all instructions could result in serious personal injury from an accidental deployment.
AC1 CHECK THE SCME (FRONT SEAT CLIMATE CONTROL MODULE) FOR ON-DEMAND DIAGNOSTIC TROUBLE CODES (DTCS)
Using a diagnostic scan tool, perform the SCME self-test.
Was DTC B272A or B272B, retrieved on-demand during the self-test?
Yes | For DTC B272A, GO to Pinpoint Test Z For DTC B272B, GO to Pinpoint Test AA |
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No | GO to AC2 |
AC2 MONITOR SCME (FRONT SEAT CLIMATE CONTROL MODULE) BLOWER MOTOR TEMPERATURE PARAMETER IDENTIFICATIONS (PIDS)
Using a diagnostic scan tool, monitor the following SCME Parameter Identifications (PIDs):
Passenger Cushion Thermal Electric Device (TED) Temperature (PCSHTMP) Passenger Back (TED) Temperature (PBKTMP) Seat cushion thermal electric device temperature (CSHTEMP) Seat back thermal electric device temperature (BKTMP)
NOTE: Make sure the temperature of the climate controlled seats has stabilized before monitoring the Parameter Identifications (PIDs). Not allowing stabilization can cause incorrect readings and lead to incorrect identification of components that are not faulty. Monitor blower motor temperature Parameter Identifications (PIDs) with the limate controlled seats OFF. Compare the PID values of the driver seat to those of the front passenger seat, this can help identify if there is a concern with the passenger seat cushion or backrest PID value readings.
Are both passenger seat blower motor temperature Parameter Identifications (PIDs) within 10° C (18° F) of the ambient temperature?
Yes | GO to AC3 |
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No | If the passenger seat cushion PID varies 10° C (18° F) or more from ambient temperature, GO to AC16 If the passenger seat backrest PID varies 10° C (18° F) or more from ambient temperature, GO to AC32 |
AC3 CONFIRM THE FAULT IS IN THE SEAT CUSHION OR THE BACKREST
Ignition OFF. Start the engine.
NOTE: A crushed seat cushion foam pad may be the cause of the fault. It may be necessary to sit on the seat or place something of reasonable size and weight on the seat to recreate the fault. After cycling the ignition and with the engine running, set the passenger seat to high heat. Allow the seat to heat for at least 15 minutes while monitoring the blower motor temperature Parameter Identifications (PIDs) of the passenger seat.
Do the passenger seat cushion blower motor and backrest blower motor Parameter Identifications (PIDs) vary more than 60° C (108° F) from each other?
Yes | If the passenger seat cushion PID is 60° C (108° F) hotter than the backrest PID, GO to AC5 If the passenger seat backrest PID is 60° C (108° F) hotter than the cushion PID, GO to AC20 |
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No | GO to AC4 |
AC4 CHECK THE BLOWER MOTOR COOLING PERFORMANCE
Check the blower motor cooling performance on the affected seat. Refer to Component Test — Blower Motor Cooling Performance in this section.
Did the blower motors pass the component test?
Yes | The DTC may have been set by extreme cabin temperatures or excessive sunload on the seat causing the system to enter recovery mode. Occupant size and weight characteristics can also be a factor. CLEAR the Diagnostic Trouble Codes (DTCs). REPEAT the self-test. TEST the system for normal operation. If a concern cannot be found or duplicated, RETURN the vehicle to the customer. |
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No | CHECK the affected seat cushion or backrest for correct installation of the climate controlled seat components (blower motor, air ducts and foam pad). CHECK for airflow restrictions (blower motor inlets and outlets, filters and ducts) and REPAIR as needed. CHECK for an intermittent wiring fault. REPAIR as needed. CLEAR the Diagnostic Trouble Codes (DTCs). REPEAT the self-test. |
AC5 CHECK FOR CORRECT BLOWER MOTOR INSTALLATION AND FOR CRUSHED FOAM
Ignition OFF. Remove the seat. REFER to: Front Seat (501-10A Front Seats, Removal and Installation). Remove the seat cushion trim cover. REFER to: Front Seat Cushion Cover (501-10A Front Seats, Removal and Installation). Inspect the seat cushion for the following:
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