10 Most Common Diagnostic Trouble Codes
| P – Code | Common Causes | Common Repairs | Cost Range |
|---|---|---|---|
| P0420 | Damaged or worn-out catalytic converter Broken O2 sensor Exhaust leak | Replace catalytic converter Replace downstream O2 sensor Seal exhaust leak | Replace catalytic converter: $400-$2400 Oxygen sensor replacement: $275-$500 Exhaust leak: $100-$200 (if welded to repair) |
| P0171 | Dirty mass airflow sensor Faulty mass airflow sensor Vacuum leaks – PCV hoses, vacuum hoses, intake manifold gasket | Clean mass airflow sensor Replace mass airflow sensor Seal vacuum leak | Clean mass airflow sensor: $20 – $100 Replace mass airflow sensor: $230 – $330 Vacuum leak $100 – $200 |
| P0300 | Spark plug is worn or broken Ignition coils are broken Spark plug wires are worn Fuel injectors are broken | Replace spark plugs Replace ignition coils Replace spark plug wires Replace fuel injectors | Spark plugs: $66-$250 Ignition Coils: $230-$640 (some cars require Intake manifold removal) Spark plug wires: $180-$240 Fuel injectors: $1500-$1900 |
| P0430 | Damaged or worn out catalytic converter Broken O2 sensor Exhaust leak | Replace catalytic converter Replace downstream O2 sensor Seal exhaust leak | Replace catalytic converter: $400-$2400 Oxygen sensor replacement: $275-$500 Exhaust leak: $100-$200 (if welded to repair) |
| P0455 | Missing, loose, or damaged gas cap Leak in EVAP line EVAP vent control valve is damaged or stuck EVAP purge volume control valve is damaged or stuck | TIghten or replace gas cap Fix leap in EVAP line Replace EVAP vent control valve Replace EVAP purge volume control valve | Missing or damaged gas cap: $0-$20 EVAP line: $20-$100 EVAP vent control valve: $150-$200 Purge volume control valve: $150-$200 |
| P0174 | Dirty mass airflow sensor Faulty mass airflow sensor Vacuum leaks – PCV hoses, vacuum hoses, intake manifold gasket Clogged fuel injectors | Clean mass airflow sensor Replace mass airflow sensor Seal vacuum leak Clean fuel injectors | Clean mass airflow sensor: $20 – $100 Replace mass airflow sensor: $230 – $330 Vacuum leak: $100 – $200 Clean fuel injectors: $50 – $80 |
| P0449 | Missing, loose, or damaged gas cap Leak in EVAP line EVAP vent control valve is damaged or stuck EVAP purge volume control valve is damaged or stuck | TIghten or replace gas cap Fix leap in EVAP line Replace EVAP vent control valve Replace EVAP purge volume control valve | Missing or damaged gas cap: $0-$20 EVAP line: $20-$100 EVAP vent control valve: $150-$200 Purge volume control valve: $150-$200 |
| P0128 | Faulty engine coolant thermostat | Replace engine coolant thermostat | Replace engine coolant thermostat: $40 – $190 |
| P0101 | Engine air filter is very dirty Mass airflow sensor is dirty or broken Catalytic converter is damaged or worn | Replace the engine air filter Replace the mass airflow sensor Replace the catalytic converter | Air filter $50-70 Mass air flow sensor $220-320 Catalytic converter $1720-1780 |
| P0303 | Spark plug #3 is worn or broken Ignition coils are broken Spark plug wires are worn Fuel injectors are broken | Replace spark plug #3 Replace ignition coils Replace spark plug wires Replace fuel injectors | Spark plugs: $66-$250 Ignition Coils: $230-$640 (some cars require Intake manifold removal) Spark plug wires: $180-$240 Fuel injectors: $1500-$1900 |
List Of Top 100 Diagnostic Trouble Codes
p0008 – Engine Position System Performance Bank 1
p0009 – The Engine Control Module (ECM) has found a difference between the bank 2 camshaft position and crankshaft position
p0010 – Intake Camshaft Actuator Circuit Open/Short (Bank 1)
p0011 – Intake Camshaft Timing- Over-Advanced Bank 1
p0012 – Intake Camshaft Position Timing- Over-Retarded (Bank 1)
p0014 – Exhaust Camshaft Timing- Over-Advanced Bank 1
p0016 – The correlation of the camshaft and crankshaft positions on bank 1 is incorrect based on the intake camshaft position sensor
p0019 – The correlation of the camshaft and crankshaft positions on bank 2 is incorrect based on the intake camshaft position sensor
p0020 – Intake Camshaft Actuator Circuit Open/Short (Bank 2)
p0021 – Intake Camshaft Position Timing- Over-Advanced (Bank 2)
p0022 – Intake Camshaft Position – Timing Over-Retarded (Bank 2)
p0024 – Exhaust Camshaft Timing- Over-Advanced Bank 2
p0031 – HO2S Heater Control Circuit Low (Bank 1, Sensor 1)
p0037 – H02S2 Heater Control Circuit Low (Bank 1, Sensor 2)
p0051 – HO2S Heater Control Circuit Low (Bank 2, Sensor 1)
p0057 – H02S2 Heater Control Circuit Low (Bank 2, Sensor 2)
p0068 – MAP/MAF – Throttle Position Correlation
p0101 – Mass Air Flow (MAF) Circuit/Performance Malfunction
p0102 – Mass or Circuit Airflow (MAF) Circuit Low Voltage Input
p0104 – Mass Air Flow (MAF) Electrical Circuit Erratic and Irregular Output
p0106 – Manifold Air Pressure (MAP) Barometric Pressure Sensor Electric Circuit Output Range and Performance Problem
p0113 – Intake Air Temperature (IAT) Sensor Circuit High Input Problem
p0117 – Engine Coolant Temperature (ECT) Sensor Circuit has lower than normal voltage
p0118 – H02S2 Heater Control Circuit Low (Bank 2, Sensor 2)
p0121 – Throttle Position Sensor (TPS) “A” Circuit Range Performance Problem
p0122 – Throttle Position Sensor/Switch (TPS) A Circuit Low Input
p0125 – Insufficient coolant temperature for closed-loop fuel control
p0128 – Coolant Thermostat Temperature Below Regulating Temperature
p0130 – Oxygen Sensor Circuit Malfunction (Bank 1, Sensor 1)
p0131 – O2 Sensor Circuit Low Voltage (Bank 1, Sensor 1)
p0133 – O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)
p0134 – O2 Sensor Circuit No Activity Detected (Bank 1, Sensor 1)
p0135 – O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
p0136 – H02S2 Heater Control Circuit Low (Bank 2, Sensor 2)
p0137 – O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)
p0138 – O2 Sensor Circuit High Voltage (Bank 1, Sensor 2)
p0141 – O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2) – Downstream
p0150 – O2 Sensor Circuit Malfunction (Bank 2, Sensor 1)
p0152 – Bank 2 Sensor 1 oxygen sensor has an abnormally high voltage reading
p0153 – O2 Sensor Circuit Slow Response (Bank 2 Sensor 1)
p0154 – O2 Sensor Circuit No Activity Detected (Bank 2, Sensor 1)
p0155 – O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)
p0156 – Oxygen Sensor Circuit Malfunction (Bank 2, Sensor 2)
p0157 – O2 Sensor Circuit Low Voltage (Bank 2, Sensor 2)
p0158 – O2 Sensor Circuit High Voltage (Bank 2, Sensor 2)
p0161 – O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2) – Downstream
p0171 – Bank 1 has too much air or not enough fuel
p0172 – Bank 1 has too much fuel or not enough air
p0174 – Bank 2 has too much air or not enough fuel
p0175 – Bank 2 has too much fuel or not enough air
p0300 – Random, Multiple Misfire Detected
p0301 – Cylinder 1 misfire detected
p0302 – Cylinder 2 misfire detected
p0303 – Cylinder 3 misfire detected
p0304 – Cylinder 4 Misfire Detected
p0305 – Cylinder 5 misfire detected
p0306 – Cylinder 6 misfire detected
p0307 – Cylinder 7 misfire detected
p0308 – Cylinder 8 misfire detected
p0309 – Cylinder 9 misfire detected
p0310 – Cylinder 10 misfire detected
p0311 – Cylinder 11 misfire detected
p0312 – Cylinder 12 misfire detected
p0316 – Engine Misfire Detected on Startup (First 1000 Revolutions)
p0320 – Ignition/Distributor Engine Speed input circuit has a malfunction
p0325 – Knock Sensor 1 Circuit Malfunction (Bank 1)
p0330 – Knock Sensor 2 Circuit Malfunction (Bank 2)
p0332 – Knock Sensor 2 Low Circuit Input (Bank 2)
p0335 – Crankshaft Position Sensor “A” Circuit Malfunction (Bank 1)
p0336 – The engine control module, ECM, has detected an improper/irregular voltage coming from the crankshaft position sensor
p0340 – Camshaft Position Sensor Circuit Malfunction
p0345 – Camshaft Position Sensor Circuit Malfunction
p0401 – Exhaust Gas Recirculation (EGR) Flow Insufficient Detected
p0404 – Exhaust Gas Recirculation Circuit Range/Performance
p0406 – Exhaust Gas Recirculation Sensor “A” Circuit High
p0410 – Secondary Air Injection System Malfunction
p0420 – Catalyst system efficiency below threshold (Bank 1)
p0421 – Bank 1 Catalytic Converter Efficiency is Below Threshold on Cold Start
p0430 – Catalyst system efficiency below threshold (Bank 2).
p0440 – Evaporative Emission Control System Malfunction
p0441 – Evaporative Emission Control System Incorrect Purge Flow
p0442 – Evaporative emission control system leak (medium)
p0443 – Evaporative Emission Control System Purge Control Valve Circuit Malfunction
p0446 – Evaporative Emission Control System Vent Control Circuit Malfunction
p0449 – Evaporative System (EVAP) Vent Circuit Control Malfunction
p0452 – Evaporative Emission Control System Pressure Sensor Low Input
p0455 – System Gross Leak Evaporative System Malfunction
p0456 – Evaporative emission control system leak (small)
p0457 – Evaporative Emission (EVAP) Control System Leak Detected
p0463 – Fuel Level Sensor Circuit High Input
p0496 – EVAP Flow During a Non-Purge Condition
p0606 – The processor in the Engine Control Module (ECM) or Power Control Module (PCM) has a fault
At FIXD, our mission is to make car ownership as simple, easy, and affordable as possible. Our research team utilizes the latest automotive data and insights to create tools and resources that help drivers get peace of mind and save money over the life of their car.
