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

• U1167 — OBD2 code U1167 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for cassette tape). Short, gentle driving to a shop is usually possible. Common culprits: water ingress in harness junctions, corroded connectors, especially in wet areas, aftermarket equipment interfering with the bus.
• U1168 — OBD2 code U1168 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for primary id). 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, a faulty module pulling the bus down.
• U1169 — SCP (J1850) Invalid or Missing Data for Primary Id (U1169): 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, damaged CAN bus wiring or short to power/ground.
• U1170 — U1170 — SCP (J1850) Invalid or Missing Data for Cellular Phone / Paging System. 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, corroded connectors, especially in wet areas, poor grounds or low battery voltage.
• U1172 — SCP (J1850) Invalid or Missing Data for Remote Button Control (U1172): 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, a faulty module pulling the bus down.
• U1173 — OBD2 code U1173 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for remote button control). Short, gentle driving to a shop is usually possible. Common culprits: corroded connectors, especially in wet areas, poor grounds or low battery voltage, a faulty module pulling the bus down.
• U1174 — U1174 — SCP (J1850) Invalid or Missing Data for Primary Id. 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, water ingress in harness junctions.
• U1175 — U1175 — SCP (J1850) Invalid or Missing Data for Primary Id. 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.
• U1176 — U1176 — SCP (J1850) Invalid or Missing Data for Primary Id. 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.
• U1177 — OBD2 code U1177 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for primary id). 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.
• U1178 — U1178 — SCP (J1850) Invalid or Missing Data for Climate Control (HVAC). 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, corroded connectors, especially in wet areas.
• U1179 — OBD2 code U1179 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for climate control (HVAC)). 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.
• U1180 — SCP (J1850) Invalid or Missing Data for Personalization (Memory) Features (U1180): 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, corroded connectors, especially in wet areas.
• U1181 — SCP (J1850) Invalid or Missing Data for Personalization (Memory) Features (U1181): 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, corroded connectors, especially in wet areas.
• U1182 — SCP (J1850) Invalid or Missing Data for Primary Id (U1182): 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, poor grounds or low battery voltage.
• U1183 — U1183 — SCP (J1850) Invalid or Missing Data for Primary Id. 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.
• U1184 — SCP (J1850) Invalid or Missing Data for Window Wiper / Washer (U1184): 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, poor grounds or low battery voltage, water ingress in harness junctions.
• U1185 — SCP (J1850) Invalid or Missing Data for Window Wiper / Washer (U1185): 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, a faulty module pulling the bus down.
• U1186 — U1186 — SCP (J1850) Invalid or Missing Data for Primary Id. 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, damaged CAN bus wiring or short to power/ground, corroded connectors, especially in wet areas.
• U1187 — OBD2 code U1187 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for primary id). Short, gentle driving to a shop is usually possible. Common culprits: poor grounds or low battery voltage, water ingress in harness junctions, aftermarket equipment interfering with the bus.
• U1188 — OBD2 code U1188 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for primary id). Short, gentle driving to a shop is usually possible. Common culprits: corroded connectors, especially in wet areas, water ingress in harness junctions, poor grounds or low battery voltage.
• U1189 — SCP (J1850) Invalid or Missing Data for Primary Id (U1189): 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, water ingress in harness junctions, corroded connectors, especially in wet areas.
• U1190 — SCP (J1850) Invalid or Missing Data for Primary Id (U1190): 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, water ingress in harness junctions.
• U1191 — U1191 — SCP (J1850) Invalid or Missing Data for Primary Id. 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, water ingress in harness junctions.