Kia OBD-II Trouble Codes

Meaning: Intake Camshaft Position Actuator Circuit/Open (Bank 1).
Common triggers/diagnostic areas: A failed or sticking intake oil control valve/CVVT solenoid, open or damaged wiring, loose or corroded connector terminals, contaminated or incorrect engine oil, restricted oil passages, low oil pressure, or—less commonly—an ECM fault.

Meaning: Intake Camshaft Timing Over-Advanced or System Performance (Bank 1).
Common triggers/diagnostic areas: A sticking CVVT oil control valve, dirty or low engine oil, incorrect oil viscosity, restricted oil passages, a worn camshaft phaser, timing-chain wear, incorrect mechanical timing, or an oil-pressure problem.

Meaning: Exhaust Camshaft Timing Over-Advanced or System Performance (Bank 1).
Common triggers/diagnostic areas: A sticking exhaust CVVT solenoid, contaminated or incorrect engine oil, restricted oil passages, a worn camshaft phaser, timing-chain problems, improper mechanical timing, or damaged wiring.

Meaning: Crankshaft Position–Camshaft Position Correlation (Bank 1, Sensor A).
Common triggers/diagnostic areas: A stretched or jumped timing chain, incorrect valve timing, a failing crankshaft or camshaft position sensor, damaged reluctor wheels, low oil pressure affecting CVVT operation, wiring faults, or an improperly installed timing component.

Meaning: Mass or Volume Air Flow Sensor Circuit Range/Performance.
Common triggers/diagnostic areas: A contaminated or failing mass airflow sensor, an improperly installed air filter, a restricted intake, cracked intake ducting, vacuum leaks, wiring or connector problems, or unmetered air entering the engine.

Meaning: Mass or Volume Air Flow Sensor Circuit Low Input.
Common triggers/diagnostic areas: A disconnected or failed MAF sensor, an open signal or power circuit, poor sensor ground, damaged connector terminals, severe intake restriction, or—less commonly—an ECM fault.

Meaning: Intake Air Temperature Sensor 1 Circuit High Input.
Common triggers/diagnostic areas: A disconnected intake air temperature sensor, an open sensor circuit, damaged wiring, corroded terminals, a failed IAT sensor or combined MAF/IAT sensor, or poor electrical contact at the connector.

Meaning: Coolant Thermostat—Coolant Temperature Below Thermostat Regulating Temperature.
Common triggers/diagnostic areas: A thermostat stuck open, low coolant, an inaccurate engine coolant temperature sensor, damaged sensor wiring, cooling fans running continuously, or unusually cold operating conditions combined with short trips.

Meaning: Oxygen Sensor Circuit Malfunction (Bank 1, Sensor 1).
Common triggers/diagnostic areas: A failing upstream oxygen or air-fuel ratio sensor, damaged wiring near the exhaust, connector contamination, an exhaust leak ahead of the sensor, poor sensor ground, or an air-fuel mixture problem.

Meaning: Oxygen Sensor Circuit Slow Response (Bank 1, Sensor 1).
Common triggers/diagnostic areas: An aging or contaminated upstream oxygen sensor, exhaust leaks, vacuum leaks, fuel-delivery problems, oil or coolant entering the combustion chamber, damaged wiring, or an engine running consistently rich or lean.

Meaning: Oxygen Sensor Heater Circuit Malfunction (Bank 1, Sensor 1).
Common triggers/diagnostic areas: A failed oxygen-sensor heater, blown fuse, damaged heater wiring, corroded connector terminals, poor ground, excessive resistance in the circuit, or an ECM heater-driver problem.

Meaning: Fuel System Too Lean (Bank 1).
Common triggers/diagnostic areas: Intake or vacuum leaks, a contaminated MAF sensor, low fuel pressure, a weak fuel pump, restricted injectors, a leaking PCV system, an exhaust leak ahead of the upstream oxygen sensor, or inaccurate sensor data.

Meaning: Fuel System Too Rich (Bank 1).
Common triggers/diagnostic areas: A leaking fuel injector, excessive fuel pressure, a contaminated MAF sensor, a restricted air filter, a faulty oxygen or air-fuel ratio sensor, an inaccurate coolant temperature sensor, or an EVAP purge valve stuck open.

Meaning: Random or Multiple-Cylinder Misfire Detected.
Common triggers/diagnostic areas: Worn spark plugs, failing ignition coils, incorrect plug gap, low fuel pressure, contaminated injectors, vacuum leaks, poor compression, incorrect valve timing, excessive oil consumption, or contaminated fuel.

Meaning: Misfire Detected in a Specific Cylinder. The final digit identifies the affected cylinder—for example, P0301 indicates cylinder 1 and P0304 indicates cylinder 4.
Common triggers/diagnostic areas: A worn spark plug, failed ignition coil, damaged coil connector, restricted or leaking injector, intake leak near the affected cylinder, low compression, valve damage, head-gasket leakage, or internal engine wear.

Meaning: Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor).
Common triggers/diagnostic areas: A failing knock sensor, damaged or pinched sensor wiring, poor connector contact, incorrect sensor installation or torque, excessive engine vibration, internal mechanical noise, poor-quality fuel, or an ECM calibration issue.

Meaning: Crankshaft Position Sensor “A” Circuit Malfunction.
Common triggers/diagnostic areas: A failed crankshaft position sensor, heat-damaged wiring, loose or contaminated connector terminals, a damaged reluctor wheel, incorrect sensor clearance, poor ground, or an intermittent loss of sensor signal.

Meaning: Camshaft Position Sensor “A” Circuit Malfunction (Bank 1 or Single Sensor).
Common triggers/diagnostic areas: A failed camshaft position sensor, damaged wiring, connector corrosion, incorrect sensor clearance, a damaged trigger wheel, timing-chain problems, low system voltage, or an ECM fault.

Meaning: Catalyst System Efficiency Below Threshold (Bank 1).
Common triggers/diagnostic areas: A deteriorated catalytic converter, prolonged engine misfires, oil or coolant consumption, incorrect fuel mixture, a lazy downstream oxygen sensor, exhaust leaks, damaged sensor wiring, or previous engine problems that overheated or contaminated the catalyst.

Meaning: Evaporative Emission System Incorrect Purge Flow.
Common triggers/diagnostic areas: A purge control solenoid stuck open or closed, restricted or disconnected EVAP hoses, a faulty canister close valve, charcoal-canister damage, wiring problems, or an ECM-command issue.

Meaning: Evaporative Emission System Leak Detected—Small Leak.
Common triggers/diagnostic areas: A loose or damaged fuel cap, a small crack in an EVAP hose, a leaking purge valve, a leaking canister close valve, a damaged charcoal canister, or a leaking fuel-tank pressure sensor seal.

Meaning: Evaporative Emission System Leak Detected—Large Leak or No Purge Flow.
Common triggers/diagnostic areas: A missing or loose fuel cap, a disconnected EVAP hose, a purge or vent valve stuck open, a cracked charcoal canister, damaged fuel-filler components, or a substantial leak in the EVAP system.

Meaning: Evaporative Emission System Leak Detected—Very Small Leak.
Common triggers/diagnostic areas: A fuel cap that is not sealing correctly, hairline cracks in EVAP hoses, minor leakage at a purge or vent valve, deteriorated O-rings, a cracked canister, or a small leak near the fuel tank or filler neck.

Meaning: Idle Air Control System RPM Lower Than Expected.
Common triggers/diagnostic areas: Carbon buildup in the electronic throttle body, restricted airflow, a sticking throttle plate, an idle air control valve problem on older models, incorrect throttle adaptation, excessive engine load, or low system voltage.

Meaning: Idle Air Control System RPM Higher Than Expected.
Common triggers/diagnostic areas: A vacuum or intake leak, a dirty or sticking throttle body, an incorrectly learned throttle position, a disconnected PCV hose, an EVAP purge valve stuck open, or an idle air control valve problem on older Kia vehicles.

Meaning: System Voltage Low.
Common triggers/diagnostic areas: A weak or discharged battery, failing alternator, loose or corroded battery terminals, damaged charging-system wiring, a slipping drive belt, excessive parasitic draw, poor engine or chassis grounds, or low voltage during starting.

Meaning: Transmission Control System Malfunction or MIL Request.
Common triggers/diagnostic areas: The transmission control module has stored one or more additional transmission-related codes. Diagnosis should include scanning the TCM for the underlying code, checking transmission fluid condition where applicable, inspecting wiring and connectors, and evaluating sensors, solenoids, software, or internal transmission operation.

Meaning: Input/Turbine Speed Sensor “A” Circuit Malfunction.
Common triggers/diagnostic areas: A failed input-speed sensor, damaged transmission wiring, poor connector contact, metallic debris on a magnetic sensor, an internal reluctor-wheel problem, low system voltage, or a TCM fault.

Meaning: Torque Converter Clutch Circuit Performance or Stuck Off.
Common triggers/diagnostic areas: A faulty torque-converter clutch solenoid, contaminated or incorrect transmission fluid, valve-body wear, damaged wiring, hydraulic-pressure loss, a worn torque converter, internal transmission wear, or outdated TCM software.

Meaning: Kia-Specific—Heated Oxygen Sensor, Bank 1 Sensor 1, Heater Circuit High Input on applicable models.
Common triggers/diagnostic areas: A heater-control wire shorted to battery voltage, damaged wiring near the exhaust, contaminated or corroded connector terminals, a failed upstream oxygen-sensor heater, incorrect replacement-sensor wiring, or an ECM heater-driver fault.

Meaning: Kia-Specific—Engine Coolant Temperature Sensor Circuit Intermittent High Input or an incorrect coolant-temperature signal on applicable models.
Common triggers/diagnostic areas: An intermittent open in the coolant-temperature sensor circuit, a loose connector, corroded terminals, damaged wiring, a failed ECT sensor, an unstable reference voltage, or—less commonly—an ECM or TCM communication problem.

Meaning: Kia-Specific—Throttle Position Signal Circuit Malfunction on applicable models.
Common triggers/diagnostic areas: A faulty throttle position sensor, a dirty or sticking throttle body, damaged wiring between the throttle sensor and control module, loose connector terminals, an incorrect throttle signal, an electronic throttle-control problem, or an ECM/TCM communication fault.

Meaning: Kia-Specific—EGR Boost or Pressure Sensor Circuit Malfunction on applicable older models.
Common triggers/diagnostic areas: A failed EGR boost or pressure sensor, an open or shorted sensor circuit, loose or corroded connectors, blocked EGR passages, damaged vacuum hoses, excessive carbon buildup, or a control-module fault. The precise system monitored can depend on the engine application.

Meaning: Kia-Specific—Knock Signal Range/Performance, commonly associated with Kia’s Knock Sensor Detection System.
Common triggers/diagnostic areas: A knock-sensor or wiring-signal problem, damaged or loose connector terminals, electrical interference, incorrect knock-sensor installation, abnormal internal engine vibration, or connecting-rod-bearing wear. Kia procedures for affected vehicles may require wiring checks, a bearing-clearance inspection, software verification, and potentially engine repair rather than automatically replacing the knock sensor.

Meaning: Kia-Specific—Knock Sensor Control Zero Test.
Common triggers/diagnostic areas: An open or shorted knock-sensor circuit, a failed knock sensor, loose or corroded connector terminals, incorrect sensor mounting, excessive mechanical engine noise, damaged wiring, or—less commonly—an ECM fault.

Meaning: Kia-Specific—Idle Air Control Valve Opening Coil Signal High.
Common triggers/diagnostic areas: An IAC control wire shorted to battery voltage, a failed or sticking idle air control valve, carbon accumulation in the idle-air passage, damaged connector terminals, incorrect circuit voltage, or an ECM driver-circuit fault. This code generally applies to older Kia models with a separate IAC valve.

Meaning: Kia-Specific—Idle Air Control Valve Closing Coil Signal Low.
Common triggers/diagnostic areas: An open IAC control circuit, wiring shorted to ground, a loose or corroded connector, a failed idle air control valve, carbon buildup that restricts valve movement, poor electrical ground, or an ECM driver-circuit fault. This code generally applies to older Kia models with a separate IAC valve.