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
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