Code Definition

B1949 — Climate Control Water Temperature Sensor Circuit Short To Ground

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

About B1949

B1949 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 B1949 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit; and a sensor-related fault — the reported value from the named sensor is out of spec.

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.

B1949 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 B1949 code is set by the Electronic Automatic Temperature Control (EATC) module when it detects a short to ground condition on the water temperature sensor circuit. This sensor monitors engine coolant temperature for HVAC control purposes, allowing the module to time heater enablement after a cold start, modulate blend door and fan strategy, and influence A/C compressor management. With a shorted signal wire, the module sees a signal voltage pinned at or near zero volts and interprets it as a maximum temperature reading (since the sensor is a negative temperature coefficient thermistor) wh...

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