OBD2 Fault Code Library

Free lookup for thousands of OBD2 trouble codes: filter by family, read short meanings, and open deeper articles. Desktop ELM327 scanner with live data and AI guidance.

OBD2 symptoms

Look up diagnostic trouble codes by what the car is doing: misfire, overheating, rough idle, a check engine light, and other common symptoms.

U0427 — U0427 — Invalid Data Received From Vehicle Security Control Module. A fault in the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Typical causes: water ingress in harness junctions, aftermarket equipment interfering with the bus, damaged CAN bus wiring or short to power/ground.
U0428 — OBD2 code U0428 flags a problem with the ABS / stability control (invalid data received from steering angle sensor module). Short, gentle driving to a shop is usually possible. Common culprits: damaged tone (reluctor) ring on the hub, faulty ABS module or pump motor, damaged sensor wiring or corroded connector.
U0429 — U0429 — Invalid Data Received From Steering Column Control Module. A fault in the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Typical causes: poor grounds or low battery voltage, water ingress in harness junctions, damaged CAN bus wiring or short to power/ground.
U0430 — OBD2 code U0430 flags a problem with the vehicle network (CAN bus) communication (invalid data received from tire pressure monitor module). Short, gentle driving to a shop is usually possible. Common culprits: water ingress in harness junctions, corroded connectors, especially in wet areas, poor grounds or low battery voltage.
U0431 — OBD2 code U0431 flags a problem with the vehicle network (CAN bus) communication (invalid data received from body control module "A"). Short, gentle driving to a shop is usually possible. Common culprits: damaged CAN bus wiring or short to power/ground, corroded connectors, especially in wet areas, aftermarket equipment interfering with the bus.
U0432 — Invalid Data Received From Multi-axis Acceleration Sensor Module (U0432): a vehicle network fault affecting the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Most often caused by poor grounds or low battery voltage, a faulty module pulling the bus down, water ingress in harness junctions.
U0433 — Invalid Data Received From Cruise Control Front Distance Range Sensor Single Sensor or Center (U0433): a vehicle network fault affecting the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Most often caused by corroded connectors, especially in wet areas, water ingress in harness junctions, a faulty module pulling the bus down.
U0434 — OBD2 code U0434 flags a problem with the vehicle network (CAN bus) communication (invalid data received from active roll control module). Short, gentle driving to a shop is usually possible. Common culprits: aftermarket equipment interfering with the bus, water ingress in harness junctions, a faulty module pulling the bus down.
U0435 — U0435 — Invalid Data Received From Power Steering Control Module Rear. A fault in the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Typical causes: aftermarket equipment interfering with the bus, water ingress in harness junctions, a faulty module pulling the bus down.
U0436 — OBD2 code U0436 flags a problem with the vehicle network (CAN bus) communication (invalid data received from differential control module front). Short, gentle driving to a shop is usually possible. Common culprits: damaged CAN bus wiring or short to power/ground, poor grounds or low battery voltage, corroded connectors, especially in wet areas.
U0438 — Invalid Data Received From Trailer Brake Control Module (U0438): a vehicle network fault affecting the ABS / stability control. Short, gentle driving to a shop is usually possible. Most often caused by failed wheel speed sensor, damaged tone (reluctor) ring on the hub, blown fuse or low voltage to the ABS module.
U0439 — OBD2 code U0439 flags a problem with the vehicle network (CAN bus) communication (invalid data received from all terrain control module). Short, gentle driving to a shop is usually possible. Common culprits: aftermarket equipment interfering with the bus, damaged CAN bus wiring or short to power/ground, water ingress in harness junctions.
U043B — U043B — Invalid Data Received From Cruise Control Front Distance Range Sensor Left. A fault in the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Typical causes: poor grounds or low battery voltage, damaged CAN bus wiring or short to power/ground, a faulty module pulling the bus down.
U043C — OBD2 code U043C flags a problem with the vehicle network (CAN bus) communication (invalid data received from cruise control front distance range sensor right). Short, gentle driving to a shop is usually possible. Common culprits: aftermarket equipment interfering with the bus, poor grounds or low battery voltage, corroded connectors, especially in wet areas.
U0440 — U0440 - Invalid Data Received From Active Safety Control Module 3 (U0440): a vehicle fault affecting the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Most often caused by aftermarket equipment interfering with the bus, corroded connectors, especially in wet areas, poor grounds or low battery voltage.
U0441 — Invalid Data Received From Emissions Critical Control Information (U0441): a vehicle network fault affecting the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Most often caused by damaged CAN bus wiring or short to power/ground, corroded connectors, especially in wet areas, aftermarket equipment interfering with the bus.
U0442 — Invalid Data Received From ECM/PCM "B" (U0442): a vehicle network fault affecting the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Most often caused by aftermarket equipment interfering with the bus, a faulty module pulling the bus down, corroded connectors, especially in wet areas.
U0443 — OBD2 code U0443 flags a problem with the vehicle network (CAN bus) communication (invalid data received from body control module "B"). Short, gentle driving to a shop is usually possible. Common culprits: damaged CAN bus wiring or short to power/ground, water ingress in harness junctions, poor grounds or low battery voltage.
U0444 — OBD2 code U0444 flags a problem with the vehicle network (CAN bus) communication (invalid data received from body control module "C). Short, gentle driving to a shop is usually possible. Common culprits: corroded connectors, especially in wet areas, damaged CAN bus wiring or short to power/ground, poor grounds or low battery voltage.
U0445 — OBD2 code U0445 flags a problem with the vehicle network (CAN bus) communication (invalid data received from body control module "D"). Short, gentle driving to a shop is usually possible. Common culprits: corroded connectors, especially in wet areas, aftermarket equipment interfering with the bus, water ingress in harness junctions.
U0446 — Invalid Data Received From Body Control Module "E" (U0446): a vehicle network fault affecting the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Most often caused by aftermarket equipment interfering with the bus, a faulty module pulling the bus down, water ingress in harness junctions.
U0447 — U0447 — Invalid Data Received From Gateway "A". A fault in the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Typical causes: aftermarket equipment interfering with the bus, a faulty module pulling the bus down, water ingress in harness junctions.
U0448 — U0448 — Invalid Data Received From Gateway "B". A fault in the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Typical causes: a faulty module pulling the bus down, poor grounds or low battery voltage, aftermarket equipment interfering with the bus.
U0449 — Invalid Data Received From Gateway "C" (U0449): a vehicle network fault affecting the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Most often caused by aftermarket equipment interfering with the bus, a faulty module pulling the bus down, corroded connectors, especially in wet areas.