OBD2 Code Lookup

Look up any diagnostic trouble code. Causes, diagnostics, and repair costs for 7,231+ codes.

How It Works

Search Your Code

Enter the DTC code from your OBD2 scanner or check engine light.

Read the Diagnosis

Get detailed causes, step-by-step diagnostics, and safety info.

Fix Your Car

Follow the repair steps or find the right parts and tools.

Popular Codes

P0300

Critical

Random/Multiple Cylinder Misfire Detected

P0420

Secondary Air Injection System Relay "B" Circuit Malfunction

P0171

Oxygen Sensor System Too Lean Fault Bank A

P0442

Evaporative Emission Control System Leak Detected (small leak)

P0455

Evaporative Emission Control System Pressure Sensor Intermittent

P0128

Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

P0507

Idle Control System RPM Higher Than Expected

P0301

Critical

Random/Multiple Cylinder Misfire Detected

P0174

System too Lean (Bank 2)P0175 System too Rich (Bank 2)

P0401

Exhaust Gas Recirculation Flow Insufficient Detected

P0135

O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)

P0340

Critical

Camshaft Position Sensor Circuit Malfunction (Bank 1)

Browse by Category

Powertrain Codes

P-codes · 4,384 codes

Engine, transmission, and emissions system codes (P-codes)

Body Codes

B-codes · 1,359 codes

Airbag, lighting, HVAC, and interior system codes (B-codes)

Chassis Codes

C-codes · 635 codes

ABS, traction control, and suspension system codes (C-codes)

Network Codes

U-codes · 853 codes

CAN bus, module communication, and network codes (U-codes)

I/M Readiness Monitors

Preparing for an emissions inspection? Learn what each readiness monitor checks and how to complete your drive cycle.

Catalyst Efficiency

Checks catalytic converter performance. Requires steady 40-60 mph cruising to complete.

EVAP System

Tests fuel vapor system for leaks. Needs 15-85% fuel level and an overnight cold soak.

Oxygen Sensor

Validates O2 sensor response and switching frequency under varying load conditions.

Misfire Monitor

Continuously tracks engine misfires via crankshaft acceleration patterns while driving.

OBDHut Mobile App

Scan and diagnose OBD2 codes right from your phone. Real-time diagnostics, live data, and AI-guided repair insights.

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