Diagnose your car in seconds — before you pay a mechanic. Enter any OBD2 trouble code (P0420, P0300, U0100) and instantly see causes, symptoms, and proven fixes.
Based on official SAE J2012 diagnostic standards used by professional mechanics worldwide, including hybrid and electric vehicles.
AutoDTCs.com is a complete OBD2 trouble code lookup for all vehicles. Search and understand diagnostic trouble codes (DTCs), including P, B, C and U codes based on official SAE J2012 standards used by professional mechanics worldwide. Each page includes clear explanations, causes, symptoms, and repair guidance.
Whether your scan tool shows a check engine light, ABS or ESP warning, airbag fault, hybrid battery issue or CAN communication problem, you'll find clear symptoms, common causes, and step-by-step repair guidance for every fault code.
Suzuki fault codes include Suzuki-specific and standard OBD-II trouble codes used across engine, transmission, ABS, body, airbag, hybrid, and communication systems. Each code page covers the official definition, common causes, symptoms, diagnostic steps, and estimated repair costs.
Powertrain Systems (P-Codes) include OBD2 trouble codes related to the engine, transmission, fuel system, ignition system, air metering, and emissions performance. These are some of the most common check engine light codes and often affect drivability, fuel economy, starting, idle quality, or shifting. Explore these P-code guides to learn what each code means, what causes it, and how to diagnose it properly.
Ford fault codes include Ford-specific and standard OBD-II trouble codes used across engine, transmission, ABS, body, airbag, hybrid, and communication systems. Each code page covers the official definition, common causes, symptoms, diagnostic steps, and estimated repair costs.
Body Systems (B-Codes) cover diagnostic trouble codes related to body electronics such as airbags, HVAC, lighting, door modules, comfort features, seats, and other interior or convenience systems. These faults may trigger warning lights, disable comfort functions, or affect safety-related body systems. Use these B-code guides to identify the meaning of each code, the likely fault area, and common repair causes.
Volvo fault codes include Volvo-specific and standard OBD-II trouble codes used across engine, transmission, ABS, body, airbag, hybrid, and communication systems. Each code page covers the official definition, common causes, symptoms, diagnostic steps, and estimated repair costs.
Chassis Systems (C-Codes) include diagnostic trouble codes related to steering, braking, suspension, traction control, stability control, and other chassis-managed systems. These faults may affect vehicle handling, braking confidence, ride behavior, or safety system performance. These C-code guides help you understand what the code means, which system is affected, and where to begin diagnosis.
Audi fault codes include Audi-specific and standard OBD-II trouble codes used across engine, transmission, ABS, body, airbag, hybrid, and communication systems. Each code page covers the official definition, common causes, symptoms, diagnostic steps, and estimated repair costs.
Network & Integration (U-Codes) cover OBD2 communication trouble codes related to control module messaging, shared vehicle networks, and integration between electronic systems. U-codes often appear when one module cannot communicate correctly with another or when network data is missing, corrupted, or implausible. These guides explain U-code meanings, likely causes, symptoms, and what to test first.
Skoda fault codes include Skoda-specific and standard OBD-II trouble codes used across engine, transmission, ABS, body, airbag, hybrid, and communication systems. Each code page covers the official definition, common causes, symptoms, diagnostic steps, and estimated repair costs.
Jeep fault codes include Jeep-specific and standard OBD-II trouble codes used across engine, transmission, ABS, body, airbag, hybrid, and communication systems. Each code page covers the official definition, common causes, symptoms, diagnostic steps, and estimated repair costs.
Volkswagen fault codes include standard OBD2 and manufacturer-specific diagnostic trouble codes found across Volkswagen models. These guides help explain VW-related engine, transmission, ABS, airbag, HVAC, body, and network communication faults with more brand-relevant context. Use this section to find Volkswagen DTC meanings, common symptoms, possible causes, and likely diagnostic paths.
Mitsubishi fault codes include standard and manufacturer-specific DTCs used on Mitsubishi vehicles across engine, transmission, chassis, body, and network systems. These guides are designed to help users understand Mitsubishi trouble code meanings, common symptoms, likely fault areas, and practical diagnostic direction. Use this category to find Mitsubishi-specific code information faster and with better context.
BYD fault codes include manufacturer-specific and standard diagnostic trouble codes found on BYD vehicles, including hybrid and electric platforms. These guides help explain BYD-related faults across powertrain, chassis, body, battery, communication, and safety systems. Use this section to find clearer BYD DTC meanings, likely causes, common symptoms, and vehicle-relevant diagnostic direction.
Toyota fault codes include Toyota-specific and standard OBD2 trouble codes used across engine, transmission, ABS, body, airbag, hybrid, and communication systems. These guides help explain what Toyota DTCs mean, what symptoms they can cause, and which systems are most likely involved. Use this category to diagnose Toyota codes more accurately and find model-relevant code explanations faster.
Lexus fault codes include manufacturer-specific and standard diagnostic trouble codes found on Lexus vehicles. These guides cover engine, transmission, body, chassis, airbag, hybrid, and communication faults with brand-specific context to make diagnosis easier. Browse this section to understand Lexus DTC meanings, symptoms, likely causes, and the systems most commonly involved.
Mercedes-Benz fault codes include standard OBD2 and manufacturer-specific diagnostic trouble codes used across Mercedes-Benz vehicles. These guides help explain Mercedes-related engine, transmission, chassis, body, air suspension, communication, and safety system faults in clearer terms. Use this category to find Mercedes-Benz DTC meanings, common symptoms, possible causes, and more focused diagnostic guidance.
Dodge fault codes include Dodge-specific and standard OBD2 trouble codes related to engine, transmission, ABS, body, airbag, and network communication systems. These guides help explain Dodge DTC meanings with practical diagnostic context, including common symptoms and likely causes. Use this category to diagnose Dodge trouble codes more efficiently and find brand-relevant fault information faster.
Kia fault codes include both manufacturer-specific and standard OBD2 diagnostic trouble codes used across Kia vehicles. These guides help explain Kia engine, transmission, ABS, airbag, body, EV, and communication system faults with clearer brand-specific context. Browse this category to find Kia DTC meanings, symptoms, likely causes, and useful diagnostic starting points.
Hyundai fault codes include Hyundai-specific and standard OBD2 diagnostic trouble codes for engine, transmission, body, safety, chassis, EV, and communication systems. These code guides help users understand Hyundai DTC meanings, likely symptoms, common causes, and practical diagnostic direction. Use this section to find clearer Hyundai trouble code explanations and faster fault identification.
Nissan fault codes include manufacturer-specific and standard OBD2 diagnostic trouble codes found on Nissan vehicles. These code guides help explain Nissan engine, transmission, ABS, body, and network-related faults, including symptoms, causes, and likely repair paths. Use this section to diagnose Nissan trouble codes more accurately and find vehicle-specific DTC information faster.
Free step-by-step guides written to professional diagnostic standards — how to test, interpret live data, and find the root cause before replacing anything.
A flashing MIL means an active misfire is damaging the catalyst right now. Know when to stop driving.
Most multi-code situations share a single cause — battery, ground, 5V reference, or CAN bus.
Both trims positive means lean. Both negative means rich. How to read the numbers and find the cause.
One weak battery cell can generate codes in six modules simultaneously. Check this before diagnosing anything else.
The snapshot taken when the fault was stored is more useful than the code itself. How to read it.
The most revealing electrical test in diagnostics and the most underused. Step-by-step procedure.
Enter the code from your scan tool (for example P0420, P0300 or U0100) into the search box at the top of this page. Each result explains the code meaning, common causes, symptoms, and possible repair steps.
Yes. Generic P0xxx codes follow the OBD2 standard and have the same meaning across all makes and models. Manufacturer-specific codes usually use P1xxx ranges or brand-specific B, C, and U codes.
P-codes relate to powertrain and emissions systems, B-codes to body and airbag systems, C-codes to chassis systems such as ABS and steering, and U-codes to module communication and CAN network faults.
Yes. AutoDTCs.com includes hybrid and EV trouble codes related to high-voltage batteries, inverters, onboard chargers, isolation faults, and other electric drive components.
The information applies to all OBD2-compliant vehicles and includes generic and manufacturer-specific fault codes for brands such as Audi, BMW, Mercedes-Benz, Toyota, Honda, Ford, GM, Volkswagen, Hyundai, Kia, Nissan, BYD, Lexus, Mitsubishi, and more.
It depends on the code. Some trouble codes indicate minor issues, while others point to serious faults that can affect drivability, safety, or emissions. Always check the code meaning and symptoms before continuing to drive.
Repair cost depends on the root cause, not just the code itself. Some codes are triggered by simple sensor or wiring faults, while others may require expensive repairs such as catalytic converter, ABS module, or transmission work.