Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Pinpoint Test AF : DTC B272C: Notes
DTC B272C
Refer to Climate Controlled Seats for schematic and connector information.
Normal Operation and Fault Conditions
The SCME is supplied voltage at all times, but the climate controlled seat system only operates with the engine running. The system can be operated with the ignition ON engine OFF by using a scan tool to bypass the climate controlled seat buttons on the touchscreen interface. When commanding a heat or cool mode operation in this manner, the climate controlled seat system only operates in 15 second intervals. Both voltage supply circuits are spliced together internal to the SCME, so if one circuit becomes open, both seats can still be operated. However, if a fault occurs setting a DTC specific to either climate controlled seat, only the affected seat is disabled by the SCME.
Cabin air is drawn through and distributed to each of the blower motors located in the seat cushion and backrest. The blower motors then heat or cool the air. The air is then directed into the foam pad where it is distributed along the surface of the cushion and backrest of the seat. Once the system is activated, the SCME uses a set of flexible algorithms to control the heating/cooling modes and the blower speed dependent on the commanded climate controlled seat settings.
A differential fault occurs when the cushion and backrest blower motors on an affected seat are reporting very different temperatures to the SCME. This may result from an airflow restriction or a circuit fault of either blower motor area. If a blower motor is clear of obstruction and is operational, check the other blower motor and circuitry on the seat. It is important to note that a blower motor with a higher temperature may be operating correctly and not the area of concern. The other blower motor may be indicating a much lower temperature, causing the DTC to set.
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| B272C | Driver Differential Temperature Fault | If there is a temperature differential between the driver backrest and cushion blower motor of 60 deg. C (108 deg. F) or more for more than 4 seconds, the blower motor is disconnected or the duct is blocked, this DTC sets. When this happens the first time in a key cycle, the SCME puts the driver seat system into recovery mode (see principles of operation). If the system is able to recover, it functions normally. If the system is able to recover and it occurs a second time in the same key cycle, the SCME shuts down the driver seat system. |
Possible Causes
- Wiring, terminals or connectors
- Restricted backrest blower motor filter
- Crushed or restricted backrest foam pad
- Cushion or backrest blower motor
- SCME
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.