B1943 OBD-II Trouble Code: Airbag Crash Sensor #1 Short to Ground

B1943 code definition

A B1943 code means that the vehicle’s onboard diagnostic system has detected a discrepancy in the voltages to two terminals in the airbag circuit, and has registered a trouble code.

What the B1943 code means

Air bag systems are designed to perform self-diagnostics. In the event of a B1943 code, voltages are off spec at certain terminals in the system, registering a trouble code as part of the self-diagnostic process.

What causes the B1943 code?

• Short circuit in #1 crash sensor
• Open circuit in left front impact sensor

What are the symptoms of the B1943 code?

• Flashing or illuminated airbag lamp on dash

How does a mechanic diagnose the B1943 code?

• Using a good quality code reader/scanner, check for any airbag-related trouble codes. B1942. B1941, B1944 and B1945 may accompany this trouble code.
• A factory wiring diagram will also be necessary for this diagnosis and repair.
• With the ignition in ON position and headlamp switch OFF, connect the scanner and check for trouble codes.
• Locate right front impact sensor. Check connectors, wiring and crimps for an intermittent problem. Perform a wiggle test. Check for any dirt, corrosion, damage or other physical problems with sensor, wiring, terminals and connectors.
• Disconnect air bag diagnostic monitor and check resistance on terminals. NOTE: disconnecting the diagnostic monitor disables the entire airbag system.
• If resistance is less than 2 ohms, replace diagnostic monitor.
• If resistance is greater than 2 ohms, disconnect right front impact sensor from harness.
• Measure resistance between the sensor connector’s pink/orange and yellow/white wires.
• Resistance should be less than 2 ohms. Locate and repair any open circuits found in #617 or #624.
• If resistance is greater than 2 ohms, replace entire right front impact sensor.
• Clear diagnostic codes and test drive vehicle to see if codes return.

Common mistakes when diagnosing the B1943 code

As with many codes, technicians often jump ahead on a B1943 code without doing a proper process of elimination and end up replacing parts unnecessarily.

How serious is the B1943 code?

A B1941 code can result in the airbag not deploying in a collision.

What repairs can fix the B1943 code?

• Replacement of left front crash sensor
• Replace/repair of wiring and connectors
• Locating and repairing short in circuit for crash sensor

Additional comments for consideration regarding the B1943 code

On many Ford vehicles, the air bag warning light will flash to alert the driver to a problem. The light will flash an indication of the code itself. In this case, it would flash four times, followed by a pause, followed by three flashes to denote 43.

Any airbag-related work is complex and might be best left up to a professional. Accidental deployment of the airbag can result in serious injury.

Need help with a B1943 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.