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

• U059B — OBD2 code U059B flags a problem with the vehicle network (CAN bus) communication (invalid data received from hybrid battery pack sensor 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.
• U059C — OBD2 code U059C flags a problem with the vehicle network (CAN bus) communication (invalid data received from drive motor control module "C"). Short, gentle driving to a shop is usually possible. Common culprits: damaged CAN bus wiring or short to power/ground, aftermarket equipment interfering with the bus, corroded connectors, especially in wet areas.
• U059D — U059D — Invalid Data Received From Drive Motor Control Module "D". 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, poor grounds or low battery voltage, aftermarket equipment interfering with the bus.
• U059F — OBD2 code U059F flags a problem with the vehicle network (CAN bus) communication (invalid data received from NOX sensor "B"). 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, poor grounds or low battery voltage.
• U1001 — SCP (J1850) Invalid or Missing Data for Primary Id (U1001): 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.
• U1002 — SCP (J1850) Invalid or Missing Data for Primary Id (U1002): 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, corroded connectors, especially in wet areas.
• U1003 — SCP (J1850) Invalid or Missing Data for Primary Id (U1003): 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.
• U1004 — OBD2 code U1004 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for EEC programming). Short, gentle driving to a shop is usually possible. Common culprits: poor grounds or low battery voltage, corroded connectors, especially in wet areas, a faulty module pulling the bus down.
• U1005 — OBD2 code U1005 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for EEC programming). 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, water ingress in harness junctions.
• U1006 — SCP (J1850) Invalid or Missing Data for Primary Id (U1006): 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, aftermarket equipment interfering with the bus, corroded connectors, especially in wet areas.
• U1007 — SCP (J1850) Invalid or Missing Data for Primary Id (U1007): 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, corroded connectors, especially in wet areas, water ingress in harness junctions.
• U1008 — U1008 — SCP (J1850) Invalid or Missing Data for Engine Torque. 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, damaged CAN bus wiring or short to power/ground.
• U1009 — OBD2 code U1009 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for engine torque). Short, gentle driving to a shop is usually possible. Common culprits: corroded connectors, especially in wet areas, aftermarket equipment interfering with the bus, poor grounds or low battery voltage.
• U1011 — OBD2 code U1011 flags a problem with the vehicle network (CAN bus) communication (SCP (J1850) invalid or missing data for engine air intake). Short, gentle driving to a shop is usually possible. Common culprits: aftermarket equipment interfering with the bus, poor grounds or low battery voltage, water ingress in harness junctions.
• U1012 — SCP (J1850) Invalid or Missing Data for Primary Id (U1012): 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, a faulty module pulling the bus down, damaged CAN bus wiring or short to power/ground.
• U1013 — OBD2 code U1013 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, poor grounds or low battery voltage, a faulty module pulling the bus down.
• U1014 — OBD2 code U1014 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, poor grounds or low battery voltage, a faulty module pulling the bus down.
• U1015 — U1015 — 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: damaged CAN bus wiring or short to power/ground, water ingress in harness junctions, poor grounds or low battery voltage.
• U1016 — OBD2 code U1016 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, a faulty module pulling the bus down, aftermarket equipment interfering with the bus.
• U1018 — U1018 — SCP (J1850) Invalid or Missing Data for Throttle. A fault in the throttle and intake air metering. Short, gentle driving to a shop is usually possible. Typical causes: wiring or connector faults in the throttle circuit, failed electronic throttle motor, contaminated or failed MAF/MAP sensor.
• U1019 — U1019 — SCP (J1850) Invalid or Missing Data for Throttle. A fault in the throttle and intake air metering. Short, gentle driving to a shop is usually possible. Typical causes: intake air leaks after the MAF sensor, failed electronic throttle motor, wiring or connector faults in the throttle circuit.
• U1020 — U1020 — SCP (J1850) Invalid or Missing Data for Air Conditioning Clutch. 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, poor grounds or low battery voltage.
• U1021 — U1021 — SCP (J1850) Invalid or Missing Data for Air Conditioning Clutch. 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, corroded connectors, especially in wet areas, aftermarket equipment interfering with the bus.
• U1022 — SCP (J1850) Invalid or Missing Data for Primary Id (U1022): 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.