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.

U0270 — U0270 - Lost Communication With Camera Module Center (U0270): a vehicle 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, a faulty module pulling the bus down, water ingress in harness junctions.
U0271 — U0271 — U0271 - Lost Communication With Camera Module Rear Center. 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, damaged CAN bus wiring or short to power/ground.
U0272 — U0272 - Lost Communication With Object Detection Control Module B (U0272): a vehicle 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, damaged CAN bus wiring or short to power/ground, water ingress in harness junctions.
U0273 — U0273 — U0273 - Lost Communication 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: water ingress in harness junctions, poor grounds or low battery voltage, a faulty module pulling the bus down.
U0274 — U0274 - Lost Communication With Active Safety Control Module 2 (U0274): a vehicle 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, a faulty module pulling the bus down, aftermarket equipment interfering with the bus.
U0275 — OBD2 code U0275 flags a problem with the vehicle network (CAN bus) communication (U0275 - lost communication with active safety control module 3). 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.
U0276 — OBD2 code U0276 flags a problem with the vehicle network (CAN bus) communication (U0276 - lost communication with active safety control module 4). Short, gentle driving to a shop is usually possible. Common culprits: poor grounds or low battery voltage, aftermarket equipment interfering with the bus, a faulty module pulling the bus down.
U0277 — U0277 - Lost Communication With Active Safety Control Module 5 (U0277): 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, poor grounds or low battery voltage, damaged CAN bus wiring or short to power/ground.
U0278 — U0278 - Lost Communication With Active Safety Control Module 6 (U0278): a vehicle 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, poor grounds or low battery voltage, water ingress in harness junctions.
U0279 — U0279 - Lost Communication With Active Safety Control Module 7 (U0279): a vehicle 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, poor grounds or low battery voltage, aftermarket equipment interfering with the bus.
U0280 — U0280 — U0280 - Lost Communication With Active Safety Control Module 8. 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, damaged CAN bus wiring or short to power/ground, corroded connectors, especially in wet areas.
U0281 — U0281 — U0281 - Lost Communication With Active Safety Control Module 9. 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, corroded connectors, especially in wet areas.
U0282 — U0282 — U0282 - Lost Communication With Active Safety Control Module 10. 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, damaged CAN bus wiring or short to power/ground, poor grounds or low battery voltage.
U0284 — OBD2 code U0284 flags a problem with the vehicle network (CAN bus) communication (U0284 - lost communication with active safety control module 12). 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, corroded connectors, especially in wet areas.
U0285 — U0285 - Lost Communication With Active Safety Control Module 13 (U0285): a vehicle fault affecting the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Most often caused by water ingress in harness junctions, a faulty module pulling the bus down, damaged CAN bus wiring or short to power/ground.
U0286 — Lost Communication With Radiator Anti Tamper Device (U0286): a vehicle network fault affecting the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Most often caused by water ingress in harness junctions, poor grounds or low battery voltage, a faulty module pulling the bus down.
U0287 — Lost Communication With Transmission Fluid Pump Module (U0287): a vehicle network fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by internal mechanical wear (clutches, torque converter), faulty transmission speed sensor, failed shift or pressure control solenoid.
U0288 — Lost Communication With DC to AC Converter Control Module "A" (U0288): 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, corroded connectors, especially in wet areas, water ingress in harness junctions.
U0289 — Lost Communication With DC to AC Converter Control Module "B" (U0289): a vehicle network fault affecting the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Most often caused by water ingress in harness junctions, corroded connectors, especially in wet areas, a faulty module pulling the bus down.
U0290 — OBD2 code U0290 flags a problem with the vehicle network (CAN bus) communication (U0290 - lost communication with active safety control module 18). Short, gentle driving to a shop is usually possible. Common culprits: poor grounds or low battery voltage, a faulty module pulling the bus down, aftermarket equipment interfering with the bus.
U0291 — OBD2 code U0291 flags a problem with the automatic transmission control (lost communication with gear shift control module "B"). Short, gentle driving to a shop is usually possible. Common culprits: internal mechanical wear (clutches, torque converter), valve body wear, faulty transmission speed sensor.
U0292 — U0292 — Lost Communication With Drive Motor Control Module "B". 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, a faulty module pulling the bus down.
U0293 — U0293 — Lost Communication With Hybrid Powertrain Control Module. 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.
U0295 — OBD2 code U0295 flags a problem with the vehicle network (CAN bus) communication (lost communication with AC to AC converter control module). Short, gentle driving to a shop is usually possible. Common culprits: water ingress in harness junctions, damaged CAN bus wiring or short to power/ground, poor grounds or low battery voltage.