B1790: Autolamp Sensor Input Circuit Failure
MediumBodyLighting
What does B1790 mean?
B1790 is a diagnostic trouble code indicating "Autolamp Sensor Input Circuit Failure". A sensor in the lighting is reporting abnormal data or has lost communication with the ECU. Sensors can fail due to age, contamination, heat exposure, or wiring issues.
Symptoms you may notice
- Check engine light (MIL) illuminated on dashboard
- Intermittent warning lights
- Erratic gauge readings
Estimated repair cost
Typical range in Australia (parts + labour)
$100 – $500 AUD
Common causes
- Faulty lighting component
- Wiring or connector issue in the related circuit
- Failed sensor providing incorrect readings
- Software/calibration issue requiring ECU update
- Related component causing secondary fault
What should you do?
Schedule a diagnostic appointment at your earliest convenience. The vehicle is generally safe to drive short distances, but the underlying issue should be addressed to prevent it from worsening.
Get a diagnosis for YOUR car
Code B1790 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.