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.

U0247 — U0247 — Lost Communication With "Seat Control Module F". 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, corroded connectors, especially in wet areas, water ingress in harness junctions.
U0248 — Lost Communication With Remote Accessory Module (U0248): 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, damaged CAN bus wiring or short to power/ground, poor grounds or low battery voltage.
U0249 — U0249 — Lost Communication With Entertainment Control Module Rear "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, damaged CAN bus wiring or short to power/ground, poor grounds or low battery voltage.
U024A — OBD2 code U024A flags a problem with the vehicle network (CAN bus) communication (lost communication with interior lighting control module). Short, gentle driving to a shop is usually possible. Common culprits: corroded connectors, especially in wet areas, poor grounds or low battery voltage, water ingress in harness junctions.
U0251 — U0251 — Lost Communication With Running Board Control Module "B". 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, poor grounds or low battery voltage, aftermarket equipment interfering with the bus.
U0252 — OBD2 code U0252 flags a problem with the vehicle network (CAN bus) communication (lost communication with lighting control module rear "B"). Short, gentle driving to a shop is usually possible. Common culprits: water ingress in harness junctions, poor grounds or low battery voltage, corroded connectors, especially in wet areas.
U0254 — U0254 — Lost Communication With Remote Start 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, aftermarket equipment interfering with the bus, damaged CAN bus wiring or short to power/ground.
U0255 — OBD2 code U0255 flags a problem with the vehicle network (CAN bus) communication (lost communication with front display interface module). Short, gentle driving to a shop is usually possible. Common culprits: a faulty module pulling the bus down, corroded connectors, especially in wet areas, aftermarket equipment interfering with the bus.
U0256 — OBD2 code U0256 flags a problem with the vehicle network (CAN bus) communication (lost communication with front controls interface module "A"). 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, a faulty module pulling the bus down.
U0257 — U0257 — Lost Communication With Front Controls/Display Interface 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, damaged CAN bus wiring or short to power/ground, poor grounds or low battery voltage.
U0258 — U0258 — Lost Communication With Radio Transceiver. 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, aftermarket equipment interfering with the bus.
U0259 — U0259 — Lost Communication With Special Purpose Vehicle Control Module "A". 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, a faulty module pulling the bus down, poor grounds or low battery voltage.
U025A — OBD2 code U025A flags a problem with the vehicle network (CAN bus) communication (lost communication with special purpose vehicle control module "B"). Short, gentle driving to a shop is usually possible. Common culprits: water ingress in harness junctions, a faulty module pulling the bus down, corroded connectors, especially in wet areas.
U025B — OBD2 code U025B flags a problem with the vehicle network (CAN bus) communication (lost communication with special purpose vehicle control module "C"). Short, gentle driving to a shop is usually possible. Common culprits: corroded connectors, especially in wet areas, poor grounds or low battery voltage, water ingress in harness junctions.
U025C — Lost Communication With Special Purpose Vehicle Control Module "D" (U025C): 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, poor grounds or low battery voltage, aftermarket equipment interfering with the bus.
U025D — Lost Communication With Front Controls Interface Module "B" (U025D): 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, aftermarket equipment interfering with the bus, corroded connectors, especially in wet areas.
U0260 — Lost Communication With Seat Control Switch Module "A" (U0260): 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, corroded connectors, especially in wet areas, poor grounds or low battery voltage.
U0261 — Lost Communication With Seat Control Switch Module "B" (U0261): 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, damaged CAN bus wiring or short to power/ground, corroded connectors, especially in wet areas.
U0262 — Lost Communication With Audio Amplifier "B" (U0262): 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, poor grounds or low battery voltage, aftermarket equipment interfering with the bus.
U0263 — OBD2 code U0263 flags a problem with the vehicle network (CAN bus) communication (lost communication with speech recognition module). Short, gentle driving to a shop is usually possible. Common culprits: aftermarket equipment interfering with the bus, corroded connectors, especially in wet areas, water ingress in harness junctions.
U0264 — U0264 — Lost Communication With Camera 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, damaged CAN bus wiring or short to power/ground.
U0266 — U0266 — U0266 - Lost Communication With Camera Module Front Left. 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, aftermarket equipment interfering with the bus.
U0268 — OBD2 code U0268 flags a problem with the vehicle network (CAN bus) communication (U0268 - lost communication with camera module left). Short, gentle driving to a shop is usually possible. Common culprits: damaged CAN bus wiring or short to power/ground, a faulty module pulling the bus down, aftermarket equipment interfering with the bus.
U0269 — OBD2 code U0269 flags a problem with the vehicle network (CAN bus) communication (U0269 - lost communication with camera module right). Short, gentle driving to a shop is usually possible. Common culprits: a faulty module pulling the bus down, corroded connectors, especially in wet areas, poor grounds or low battery voltage.