Operation CHARM: Car repair manuals for everyone.

Test L

PINPOINT TEST L: DTC B2729 - CUSHION OVER-TEMP DETECTED/DTC B2730 - BACK OVER-TEMP DETECTED/DTC B2731 - DIFFERENTIAL TEMPERATURE FAULT - PASSENGER SEAT


Test L1:






Test L2-L5:






Test L6-L8:






Test L9-L10:






Test L11-L13:






Test L13-L14:






Test L15-L17:






Test L17-L18:






Test L19-L21:






Test L21-L22:






Test L23-L24:






Normal Operation
Each thermo-electric device (TED) contains an internal temperature sensor (thermistor) that is used by the climate controlled seat module (CCSM) to monitor the temperature of each (TED). Based on the temperature of a TED, the internal sensor resistance will vary the voltage on circuit 1548 (DG/LG) (seat cushion TED) and circuit 1549 (DB/OG) (backrest TED).

Possible Causes
An over-temp or differential temperature fault can be caused by:
- wiring, terminals, or connectors.
- damaged, restricted, or disconnected air ducts.
- worn, damaged, or incorrectly installed foam wedge, cushion foam, or seat cushion trim cover.
- airflow leaks.
- collapsed airflow channels in the seat cushion foam.
- incorrect installation of a TED.
- TED.
- CCSM.