Code Definition

B1849 — Climate Control Temperature Differential Circuit Failure

System: Body  |  Type: Manufacturer-Specific  |  Make: Ford

About B1849

B1849 is a manufacturer-specific body diagnostic trouble code recorded for Ford vehicles. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B1849 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

Scanning & clearing: Body (B) codes are often stored in the body control module, airbag module, or climate module. A basic OBD-II tool usually will not read body codes — an enhanced or OEM-level scan tool is typically required.

B1849 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The B1849 fault code is set by the Electronic Automatic Temperature Control (EATC) module or Body Control Module (BCM) when it detects a circuit failure on the temperature differential blend door feedback potentiometer. The temperature differential potentiometer is a position sensor on the blend door actuator (or an in cabin temperature reference assembly on dual zone systems) that reports the current door position or the differential between desired and actual cabin temperature. The module supplies a 5V reference to the potentiometer and reads back a voltage proportional to position; when the...

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