Did the SRS prove out successfully?
Yes | Repair is complete. RETURN the vehicle to the customer. |
|---|---|
No | REFER to: Airbag Supplemental Restraint System (SRS) (501-20B Supplemental Restraint System, Diagnosis and Testing). |
DTC B272C
Refer to Wiring Diagrams Cell 119 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 diagnostic scan tool to bypass the climate controlled seat buttons on the touchscreen and FCIM. 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 dependant 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° C (108° F) or more for more than 4 seconds, or if the blower motor is disconnected or the duct is blocked, this DTC sets. When this happens for 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 returns to normal function. 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 blower motor filter Crushed or restricted backrest foam pad Cushion or backrest blower motor SCME
PINPOINT TEST AB : DTC B272C
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.
AB1 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 B2729 or B2730, retrieved on-demand during the self-test?
Yes | For DTC B2729, GO to Pinpoint Test AF For DTC B2730, GO to Pinpoint Test AG |
|---|---|
No | GO to AB2 |
AB2 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 climate 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 driver seat cushion or backrest PID value readings.
Are both driver seat blower motor temperature Parameter Identifications (PIDs) within 10° C (18° F) of the ambient temperature?
2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.