Code Definition

B1B42 (12-AF) — Left Front Inner Sensor

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

About B1B42

B1B42 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 B1B42 is stored, the module has detected 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.

B1B42 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 Parking Aid Module (PAM) supervises each ultrasonic parking sensor by supplying voltage and reading a return signal that varies as the sensor transmits an ultrasonic burst and listens for the echo. DTC B1B42:12 is set when the PAM detects a short to battery condition on the left front inner ultrasonic sensor circuit, meaning higher than expected voltage is present on the signal or supply line. The left front inner sensor is mounted inboard of the left outer sensor in the front bumper array and provides obstacle detection in the centre to left portion of the forward sweep during low speed m...

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