Code Definition

B1223 — Fuel Temperature Sensor #1 Circuit Open

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

About B1223

B1223 is a manufacturer-specific body diagnostic trouble code. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B1223 is stored, the module has detected an open (broken or disconnected) electrical path 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.

B1223 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

Fuel Temperature Sensor #1 is a negative temperature coefficient (NTC) thermistor that reports fuel temperature to the control module, typically mounted on the fuel rail, return line, or integrated into the fuel pump module assembly. DTC B1223 sets specifically when the control module detects an open circuit, meaning the signal voltage is sitting at or very near the 5V reference voltage for a sustained period with no plausible temperature reading returned. Since the sensor is an NTC thermistor, a missing sensor or broken wire leaves the signal pin pulled up to reference by the internal bias re...

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