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Diagnostic Codes List

This page provides a structured reference list of automotive Diagnostic Trouble Codes (DTCs) used by modern vehicle onboard diagnostic systems.

Diagnostic codes are generated by the ECU when a fault is detected in the engine, transmission, emissions system, vehicle network, or other electronic control systems. Each code represents a specific fault condition and serves as the starting point for vehicle diagnostics and troubleshooting.

This Diagnostic Codes List allows technicians and automotive professionals to browse fault codes by system category, quickly identify code meanings, and access detailed diagnostic information for each individual code.

By selecting a specific diagnostic code, you can view in-depth explanations including fault descriptions, affected systems, common causes, diagnostic procedures, and recommended inspection steps based on real-world diagnostic scenarios.

This list is designed to support efficient fault identification and accurate diagnosis using professional diagnostic tools, live data analysis, and vehicle-specific diagnostic workflows.

Select by System

P0300

Diagnostic trouble code P0300 indicates random or multiple cylinder misfires detected by the ECM

P0301

Diagnostic trouble code P0301 indicates a misfire detected in cylinder 1

P0302

Diagnostic trouble code P0302 indicates a misfire detected in cylinder 2

P0303

Diagnostic trouble code P0303 indicates a misfire detected in cylinder 3

P0304

Diagnostic trouble code P0304 indicates a misfire detected in cylinder 4

P0305

Diagnostic trouble code P0305 indicates a misfire detected in cylinder 5

P0306

Diagnostic trouble code P0306 indicates a misfire detected in cylinder 6

P0307

Diagnostic trouble code P0307 indicates a misfire detected in cylinder 7

P0308

Diagnostic trouble code P0308 indicates a misfire detected in cylinder 8

P0335

Diagnostic trouble code P0335 indicates a malfunction in the crankshaft position sensor circuit detected by the ECM

P0336

Diagnostic trouble code P0336 indicates that the crankshaft position sensor signal is outside the expected range or performance limits

P0337

Diagnostic trouble code P0337 indicates a low input signal from the crankshaft position sensor circuit

P0338

Diagnostic trouble code P0338 indicates a high input signal from the crankshaft position sensor circuit

P0339

Diagnostic trouble code P0339 indicates an intermittent signal from the crankshaft position sensor circuit

P0340

Diagnostic trouble code P0340 indicates a malfunction in the camshaft position sensor circuit detected by the ECM

P0341

Diagnostic trouble code P0341 indicates that the camshaft position sensor signal is outside the expected range or performance limits

P0342

Diagnostic trouble code P0342 indicates a low input signal from the camshaft position sensor circuit

P0343

Diagnostic trouble code P0343 indicates a high input signal from the camshaft position sensor circuit

P0344

Diagnostic trouble code P0344 indicates an intermittent signal from the camshaft position sensor circuit

P0350

Diagnostic trouble code P0350 indicates a malfunction in the ignition coil primary/secondary circuit

P0351

Diagnostic trouble code P0351 indicates a malfunction in the ignition coil A primary/secondary circuit

P0352

Diagnostic trouble code P0352 indicates a malfunction in the ignition coil B primary/secondary circuit

P0353

Diagnostic trouble code P0353 indicates a malfunction in the ignition coil C primary/secondary circuit

P0354

Diagnostic trouble code P0354 indicates a malfunction in the ignition coil D primary/secondary circuit

P0440

Diagnostic trouble code P0440 indicates a general malfunction in the evaporative emission control (EVAP) system

P0441

Diagnostic trouble code P0441 indicates incorrect purge flow detected in the EVAP system

P0193

Diagnostic trouble code P0193 indicates high input from the fuel rail pressure sensor

P0194

Diagnostic trouble code P0194 indicates an intermittent signal from the fuel rail pressure sensor circuit

P0205

Diagnostic trouble code P0205 indicates a malfunction in the fuel injector circuit for cylinder 5

P0206

Diagnostic trouble code P0206 indicates a malfunction in the fuel injector circuit for cylinder 6

P0207

Diagnostic trouble code P0207 indicates a malfunction in the fuel injector circuit for cylinder 7

P0208

Diagnostic trouble code P0208 indicates a malfunction in the fuel injector circuit for cylinder 8

P0234

Diagnostic trouble code P0234 indicates a turbocharger boost pressure too high condition

P0299

Diagnostic trouble code P0299 indicates turbocharger underboost condition (Bank 1)

P0309

Diagnostic trouble code P0309 indicates a misfire detected in cylinder 9 (if equipped)

P0310

Diagnostic trouble code P0310 indicates a misfire detected during engine start-up

P0320

Diagnostic trouble code P0320 indicates a malfunction in the knock sensor circuit

P0325

Diagnostic trouble code P0325 indicates a malfunction in the knock sensor 1 circuit (Bank 1)

P0330

Diagnostic trouble code P0330 indicates a malfunction in the knock sensor 2 circuit (Bank 2, if equipped)

P0404

Diagnostic trouble code P0404 indicates an EGR position sensor range or performance problem

P0405

Diagnostic trouble code P0405 indicates low input from the EGR position sensor

P0406

Diagnostic trouble code P0406 indicates high input from the EGR position sensor

P0410

Diagnostic trouble code P0410 indicates a malfunction in the secondary air injection system

P0411

Diagnostic trouble code P0411 indicates incorrect airflow detected in the secondary air injection system

P0180

Diagnostic trouble code P0180 indicates a fuel temperature sensor circuit malfunction

P0183

Diagnostic trouble code P0183 indicates high input from the fuel temperature sensor

P0184

Diagnostic trouble code P0184 indicates intermittent signal from the fuel temperature sensor

P0190

Diagnostic trouble code P0190 indicates a fuel rail pressure sensor circuit malfunction

P0191

Diagnostic trouble code P0191 indicates fuel rail pressure sensor range or performance issues

P0192

Diagnostic trouble code P0192 indicates low input from the fuel rail pressure sensor

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