B05xx OBD-II Codes (B0500–B0599)
100 fault codes in the B05xx range. Click any code for causes, diagnostic steps, severity, and common fixes.
B0500 moderate
Horn Circuit Malfunction
B0501 moderate
Horn Circuit Open
B0502 moderate
Horn Circuit Short to Ground
B0503 moderate
Horn Circuit Short to Battery
B0504 moderate
Horn Relay Malfunction
B0505 moderate
Horn Relay Circuit Open
B0506 moderate
Horn Switch Circuit
B0507 moderate
Horn Switch Open
B0508 moderate
Horn Switch Short
B0509 moderate
Dual-Tone Horn Circuit
B0510 moderate
Horn Low Note Circuit
B0511 moderate
Horn High Note Circuit
B0512 moderate
Steering Wheel Horn Contact
B0513 moderate
Horn Timer Circuit
B0514 moderate
Horn Volume Control Circuit
B0515 moderate
Emergency Horn Circuit
B0516 moderate
Horn Ground Circuit
B0517 moderate
Horn Power Supply
B0518 moderate
Horn Module Communication
B0519 moderate
Horn System Self-Test Failure
B0520 low
Theft Deterrent System Malfunction
B0521 low
Alarm Horn Circuit Open
B0522 low
Alarm Horn Circuit Short
B0523 low
Alarm Siren Module Fault
B0524 low
Alarm Trigger Sensor Circuit
B0525 low
Hood Tamper Switch Circuit
B0526 low
Hood Tamper Switch Open
B0527 low
Trunk Tamper Switch Circuit
B0528 low
Trunk Tamper Switch Open
B0529 low
Glass Break Sensor Circuit
B0530 low
Glass Break Sensor Fault
B0531 low
Tilt Sensor Circuit Malfunction
B0532 low
Tilt Sensor Calibration Error
B0533 low
Interior Motion Sensor Circuit
B0534 low
Interior Motion Sensor Fault
B0535 low
Alarm Control Module Communication
B0536 low
Alarm Control Module Internal Error
B0537 low
Alarm LED Indicator Circuit
B0538 low
Alarm Status Output Circuit
B0539 critical
Immobilizer Communication Fault
B0540 critical
Immobilizer Antenna Ring Circuit
B0541 critical
Immobilizer Key Transponder Error
B0542 critical
Immobilizer Control Module Fault
B0543 critical
Engine Start Inhibit Circuit
B0544 critical
Starter Interrupt Relay Circuit
B0545 low
Alarm System Voltage Monitor
B0546 low
Panic Mode Circuit
B0547 low
Alarm Arm/Disarm Indicator
B0548 low
Vehicle Intrusion Detection Circuit
B0549 low
Perimeter Alarm Sensor
B0550 low
Keyless Entry Receiver Circuit
B0551 low
Keyless Entry Receiver Antenna
B0552 low
Remote Key Fob Signal Not Detected
B0553 low
Key Fob Battery Low Signal
B0554 low
Keyless Entry Module Communication
B0555 low
Keyless Entry Module Internal Error
B0556 low
Smart Key Antenna Front Circuit
B0557 low
Smart Key Antenna Rear Circuit
B0558 low
Smart Key Antenna Interior Circuit
B0559 low
Smart Key Antenna Trunk Circuit
B0560 moderate
Push Button Start Circuit Malfunction
B0561 moderate
Push Button Start Switch Fault
B0562 moderate
Push Button Start Module Error
B0563 low
Smart Key System Malfunction
B0564 low
Smart Key Detection Range Error
B0565 low
Smart Key Authentication Failure
B0566 low
Keyless Entry Lock Button Circuit
B0567 low
Keyless Entry Unlock Button Circuit
B0568 low
Keyless Entry Trunk Release Circuit
B0569 low
Keyless Entry Panic Button Circuit
B0570 low
Key Fob Programming Error
B0571 low
Key Fob Frequency Interference
B0572 low
Passive Entry System Fault
B0573 low
Passive Entry Antenna Driver Door
B0574 low
Passive Entry Antenna Passenger Door
B0575 low
Passive Entry Touch Sensor
B0576 low
Door Handle Touch Sensor Circuit
B0577 low
Door Handle Touch Sensor Open
B0578 low
Passive Entry Capacitive Sensor
B0579 low
Proximity Key Locator Fault
B0580 low
Key Left in Vehicle Warning Circuit
B0581 low
Key Not Detected Warning
B0582 low
Smart Entry Control Module Fault
B0583 moderate
Remote Start Communication Error
B0584 moderate
Remote Start Module Fault
B0585 moderate
Remote Start Temperature Sensor
B0586 moderate
Remote Start Timer Circuit
B0587 moderate
Remote Start Abort Circuit
B0588 low
Key Slot Reader Malfunction
B0589 low
Backup Key Detection Circuit
B0590 critical
Steering Lock Actuator Circuit
B0591 critical
Steering Lock Position Sensor
B0592 critical
Electronic Steering Lock Module
B0593 critical
Steering Lock Communication Error
B0594 critical
Steering Lock Malfunction
B0595 low
Key Cylinder Switch Circuit
B0596 low
Key Cylinder Position Sensor
B0597 low
Ignition Switch Circuit
B0598 low
Start/Stop Button Illumination
B0599 low
Key System Voltage Monitor