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.

U0319 — U0319 — Software Incompatibility with Steering Effort 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, poor grounds or low battery voltage, damaged CAN bus wiring or short to power/ground.
U0320 — Software Incompatibility with Power Steering Control Module (U0320): 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, damaged CAN bus wiring or short to power/ground, a faulty module pulling the bus down.
U0321 — U0321 — Software Incompatibility with Ride Level Control Module. A fault in the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Typical causes: corroded connectors, especially in wet areas, water ingress in harness junctions, aftermarket equipment interfering with the bus.
U0322 — U0322 — Software Incompatibility with Body Control Module. A fault in the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Typical causes: corroded connectors, especially in wet areas, poor grounds or low battery voltage, a faulty module pulling the bus down.
U0323 — OBD2 code U0323 flags a problem with the vehicle network (CAN bus) communication (software incompatibility with instrument panel control module). Short, gentle driving to a shop is usually possible. Common culprits: aftermarket equipment interfering with the bus, water ingress in harness junctions, poor grounds or low battery voltage.
U0324 — Software Incompatibility with HVAC Control Module (U0324): 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, damaged CAN bus wiring or short to power/ground, poor grounds or low battery voltage.
U0325 — Software Incompatibility with Auxiliary Heater Control Module (U0325): a vehicle network fault affecting the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Most often caused by a faulty module pulling the bus down, corroded connectors, especially in wet areas, poor grounds or low battery voltage.
U0326 — U0326 — Software Incompatibility with Vehicle Immobilizer 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, damaged CAN bus wiring or short to power/ground, water ingress in harness junctions.
U0327 — OBD2 code U0327 flags a problem with the vehicle network (CAN bus) communication (software incompatibility with vehicle security control module). Short, gentle driving to a shop is usually possible. Common culprits: damaged CAN bus wiring or short to power/ground, aftermarket equipment interfering with the bus, corroded connectors, especially in wet areas.
U0328 — Software Incompatibility with Steering Angle Sensor Module (U0328): a vehicle network fault affecting the ABS / stability control. Short, gentle driving to a shop is usually possible. Most often caused by damaged sensor wiring or corroded connector, damaged tone (reluctor) ring on the hub, blown fuse or low voltage to the ABS module.
U0329 — OBD2 code U0329 flags a problem with the vehicle network (CAN bus) communication (software incompatibility with steering column control module). Short, gentle driving to a shop is usually possible. Common culprits: aftermarket equipment interfering with the bus, corroded connectors, especially in wet areas, a faulty module pulling the bus down.
U0330 — OBD2 code U0330 flags a problem with the vehicle network (CAN bus) communication (software incompatibility with tire pressure monitor module). Short, gentle driving to a shop is usually possible. Common culprits: aftermarket equipment interfering with the bus, a faulty module pulling the bus down, corroded connectors, especially in wet areas.
U0331 — OBD2 code U0331 flags a problem with the vehicle network (CAN bus) communication (software incompatibility with body control module "A"). Short, gentle driving to a shop is usually possible. Common culprits: poor grounds or low battery voltage, damaged CAN bus wiring or short to power/ground, water ingress in harness junctions.
U0332 — U0332 — Multi-Axis Sensor Software Incompatibility. U0332 can leave ABS, ESC, or related chassis systems in a limited mode even if the vehicle drives normally.
U0333 — U0333 — Gear Shift Module B Software Incompatibility. Driving may be possible if U0333 is historical and shifts remain normal, but a software incompatibility can cause erratic shifting or reduced transmission operation.
U0334 — U0334 — Radio Software Incompatibility. U0334 usually affects radio and integrated convenience functions rather than propulsion, but audio, navigation, communications, or camera-related features may be unreliable.
U0335 — U0335 — Hybrid Battery Sensor Software Incompatibility. U0335 can affect battery monitoring and hybrid operating control.
U0336 — U0336 — Restraints Module Software Compatibility Fault. U0336 is a software or configuration incompatibility rather than proof that the airbags are physically damaged, but it can affect restraint-system controls and indicators.
U0337 — OBD2 code U0337 flags a problem with the vehicle network (CAN bus) communication (U0337 - software incompatibility with object detection control module). 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, water ingress in harness junctions.
U0338 — U0338 — U0338 - Software Incompatibility With Active Safety Control Module 1. 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, water ingress in harness junctions.
U0339 — OBD2 code U0339 flags a problem with the vehicle network (CAN bus) communication (U0339 - software incompatibility with active safety control module 2). Short, gentle driving to a shop is usually possible. Common culprits: aftermarket equipment interfering with the bus, poor grounds or low battery voltage, damaged CAN bus wiring or short to power/ground.
U0340 — U0340 - Lost Communication With Active Safety Control Module 28 (U0340): a vehicle 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, a faulty module pulling the bus down, corroded connectors, especially in wet areas.
U0341 — U0341 — U0341 - Lost Communication With Active Safety Control Module 29. A fault in the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Typical causes: damaged CAN bus wiring or short to power/ground, water ingress in harness junctions, poor grounds or low battery voltage.
U0342 — U0342 — U0342 - Lost Communication With Active Safety Control Module 30. A fault in the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Typical causes: corroded connectors, especially in wet areas, aftermarket equipment interfering with the bus, water ingress in harness junctions.