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.

• Engine misfire
• Engine overheating
• Rough idle
• Check engine light
• Poor fuel economy
• Hard starting
• Engine stalling
• Catalytic converter efficiency
• Oxygen sensor fault
• EVAP leak
• Thermostat not reaching temperature
• Lean air-fuel mixture
• Rich air-fuel mixture
• EGR flow fault
• Engine knock
• Charging system
• Throttle position
• Mass airflow sensor
• Turbo underboost
• Coolant temperature sensor
• Transmission fault

• U017C — U017C — Lost Communication With "Restraints System Sensor M". A fault in the airbag / restraint system (SRS). Short, gentle driving to a shop is usually possible. Typical causes: failed clockspring (driver airbag circuit), faulty impact or occupancy sensor, SRS control module fault or stored crash data.
• U017D — Lost Communication With "Restraints System Sensor N" (U017D): a vehicle network fault affecting the airbag / restraint system (SRS). Short, gentle driving to a shop is usually possible. Most often caused by SRS control module fault or stored crash data, failed clockspring (driver airbag circuit), depleted backup battery or low system voltage.
• U017E — U017E — Lost Communication With Seatbelt Pretensioner Module "A". A fault in the airbag / restraint system (SRS). Short, gentle driving to a shop is usually possible. Typical causes: SRS control module fault or stored crash data, depleted backup battery or low system voltage, failed clockspring (driver airbag circuit).
• U017F — Lost Communication With Seatbelt Pretensioner Module "B" (U017F): a vehicle network fault affecting the airbag / restraint system (SRS). Short, gentle driving to a shop is usually possible. Most often caused by depleted backup battery or low system voltage, SRS control module fault or stored crash data, damaged wiring under seats or in the steering column.
• U0180 — U0180 — Lost Communication With Automatic Lighting Control Module. 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, a faulty module pulling the bus down, water ingress in harness junctions.
• U0182 — OBD2 code U0182 flags a problem with the vehicle network (CAN bus) communication (lost communication with front lighting control module). 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.
• U0183 — U0183 — Lost Communication With Rear Lighting 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, damaged CAN bus wiring or short to power/ground.
• U0184 — OBD2 code U0184 flags a problem with the vehicle network (CAN bus) communication (lost communication with radio). Short, gentle driving to a shop is usually possible. Common culprits: aftermarket equipment interfering with the bus, a faulty module pulling the bus down, poor grounds or low battery voltage.
• U0185 — Lost Communication With Antenna Control Module (U0185): 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, water ingress in harness junctions, aftermarket equipment interfering with the bus.
• U0186 — OBD2 code U0186 flags a problem with the vehicle network (CAN bus) communication (lost communication with audio amplifier "A"). Short, gentle driving to a shop is usually possible. Common culprits: poor grounds or low battery voltage, a faulty module pulling the bus down, corroded connectors, especially in wet areas.
• U0187 — Lost Communication With Digital Disc Player/Changer Module "A" (U0187): 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, a faulty module pulling the bus down, aftermarket equipment interfering with the bus.
• U0188 — U0188 — Lost Communication With Digital Disc Player/Changer Module "B". 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, corroded connectors, especially in wet areas.
• U0189 — OBD2 code U0189 flags a problem with the vehicle network (CAN bus) communication (lost communication with digital disc player/changer module "C"). Short, gentle driving to a shop is usually possible. Common culprits: poor grounds or low battery voltage, water ingress in harness junctions, damaged CAN bus wiring or short to power/ground.
• U0190 — Lost Communication With Digital Disc Player/Changer Module "D" (U0190): 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.
• U0191 — Lost Communication With Television (U0191): 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, aftermarket equipment interfering with the bus, water ingress in harness junctions.
• U0192 — Lost Communication With Personal Computer (U0192): 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, water ingress in harness junctions, a faulty module pulling the bus down.
• U0193 — Lost Communication With "Digital Audio Control Module A" (U0193): 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, aftermarket equipment interfering with the bus, damaged CAN bus wiring or short to power/ground.
• U0194 — Lost Communication With "Digital Audio Control Module B" (U0194): 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, aftermarket equipment interfering with the bus, poor grounds or low battery voltage.
• U0195 — U0195 — Lost Communication With Subscription Entertainment Receiver 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, a faulty module pulling the bus down.
• U0196 — OBD2 code U0196 flags a problem with the vehicle network (CAN bus) communication (lost communication with rear seat entertainment control module). Short, gentle driving to a shop is usually possible. Common culprits: aftermarket equipment interfering with the bus, water ingress in harness junctions, corroded connectors, especially in wet areas.
• U0197 — U0197 — Lost Communication With Telephone Control Module. 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, water ingress in harness junctions.
• U0198 — Lost Communication With Telematic Control Module (U0198): 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, a faulty module pulling the bus down, poor grounds or low battery voltage.
• U0199 — U0199 — Lost Communication With "Door Control Module A". 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, a faulty module pulling the bus down, water ingress in harness junctions.
• U0200 — OBD2 code U0200 flags a problem with the vehicle network (CAN bus) communication (lost communication with "door 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, aftermarket equipment interfering with the bus.