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

• U1134 — U1134 — SCP (J1850) Invalid or Missing Data for Ignition Switch / Starter. A fault in the ignition system. Short, gentle driving to a shop is usually possible. Typical causes: failed ignition coil or coil pack, faulty ignition control circuit in the ECM, moisture or oil in the spark plug wells.
• U1135 — U1135 — SCP (J1850) Invalid or Missing Data for Ignition Switch / Starter. A fault in the ignition system. Short, gentle driving to a shop is usually possible. Typical causes: moisture or oil in the spark plug wells, damaged coil wiring or connector, worn spark plugs or wrong plug gap.
• U1136 — OBD2 code U1136 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for telltales). 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.
• U1137 — SCP (J1850) Invalid or Missing Data for Telltales (U1137): 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.
• U1138 — U1138 — 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, a faulty module pulling the bus down, damaged CAN bus wiring or short to power/ground.
• U1141 — SCP (J1850) Invalid or Missing Data for Gateway (U1141): 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, a faulty module pulling the bus down, corroded connectors, especially in wet areas.
• U1142 — SCP (J1850) Invalid or Missing Data for Primary Id (U1142): 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, damaged CAN bus wiring or short to power/ground.
• U1143 — SCP (J1850) Invalid or Missing Data for Primary Id (U1143): 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.
• U1146 — OBD2 code U1146 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for vehicle security). Short, gentle driving to a shop is usually possible. Common culprits: damaged CAN bus wiring or short to power/ground, corroded connectors, especially in wet areas, water ingress in harness junctions.
• U1147 — SCP (J1850) Invalid or Missing Data for Vehicle Security (U1147): 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, water ingress in harness junctions, aftermarket equipment interfering with the bus.
• U1149 — OBD2 code U1149 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for audio control). 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, aftermarket equipment interfering with the bus.
• U1150 — SCP (J1850) Invalid or Missing Data for Audible Warnings (U1150): 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, a faulty module pulling the bus down.
• U1151 — SCP (J1850) Invalid or Missing Data for Audible Warnings (U1151): 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, aftermarket equipment interfering with the bus, water ingress in harness junctions.
• U1152 — OBD2 code U1152 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for experimental #3). Short, gentle driving to a shop is usually possible. Common culprits: corroded connectors, especially in wet areas, damaged CAN bus wiring or short to power/ground, water ingress in harness junctions.
• U1153 — U1153 — SCP (J1850) Invalid or Missing Data for Experimental #3. 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, water ingress in harness junctions, aftermarket equipment interfering with the bus.
• U1154 — OBD2 code U1154 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for compact disc). 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.
• U1156 — U1156 — SCP (J1850) Invalid or Missing Data for Digital Signal Processing. 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, a faulty module pulling the bus down, water ingress in harness junctions.
• U1157 — OBD2 code U1157 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for digital signal processing). 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.
• U1160 — OBD2 code U1160 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: damaged CAN bus wiring or short to power/ground, water ingress in harness junctions, aftermarket equipment interfering with the bus.
• U1161 — SCP (J1850) Invalid or Missing Data for Primary Id (U1161): 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, damaged CAN bus wiring or short to power/ground.
• U1163 — SCP (J1850) Invalid or Missing Data for Digital Audio Tape (U1163): 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, aftermarket equipment interfering with the bus.
• U1164 — OBD2 code U1164 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for tuner / receiver). Short, gentle driving to a shop is usually possible. Common culprits: aftermarket equipment interfering with the bus, a faulty module pulling the bus down, water ingress in harness junctions.
• U1165 — OBD2 code U1165 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for tuner / receiver). Short, gentle driving to a shop is usually possible. Common culprits: a faulty module pulling the bus down, water ingress in harness junctions, aftermarket equipment interfering with the bus.
• U1166 — SCP (J1850) Invalid or Missing Data for Cassette Tape (U1166): 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, damaged CAN bus wiring or short to power/ground.