Pinpoint Test BP : DTC B272D: Notes

Pinpoint Test BP: DTC B272D 

Refer to Wiring Diagrams Climate Controlled Seats for schematic and connector information.

Normal Operation 

The Passenger Climate Controlled Seat Module - 2 (PCSM-2) monitors the temperature sensor. If the temperature exceeds the specified limits, the DTC will be set.

A differential fault occurs when the cushion and backrest Thermo-Electric Devices (TEDs) are reporting different temperatures to the PCSM-2. This may be caused by airflow restriction or a circuit fault of either TED. If a TED and manifold is clear of obstruction and is operational, the other TED and circuitry on the seat should be checked. It is important to note that a TED with a higher temperature may be operating correctly and not the area of concern. The other TED may be indicating a much lower temperature, causing the DTC to set.

• DTC B272D (Passenger Differential Temperature Fault) - If there is a temperature differential between the RH rear backrest and cushion TED of 60°C (108°F) or more for more than 4 seconds, the TED is disconnected or the duct is blocked, this DTC will set. When this happens the first time in an ignition cycle, the PCSM-2 puts the RH rear seat system into recovery mode (see Principles of Operation in this article). If the system is able to recover, it will function normally. If the system is able to recover and it occurs a second time in the same ignition cycle, the PCSM-2 will shut down the RH rear seat system.

This pinpoint test is intended to diagnose the following: 

• Wiring, terminals or connectors
• Restricted cushion or backrest TED filter
• Crushed or restricted cushion or backrest foam pad
• Cushion or backrest TED assembly
• PCSM-2