What does the check engine light mean?

The check engine light indicates your vehicle's onboard diagnostics has detected a problem with the engine, transmission, or emissions system. It can range from a loose gas cap to serious engine damage. A flashing check engine light means stop driving immediately.

Can I drive with a P0420 code?

P0420 (Catalyst System Efficiency Below Threshold) is typically safe for short drives but should be diagnosed soon. The catalytic converter is not operating at peak efficiency, which may cause failed emissions tests. Long-term driving without repair can damage other components.

How much does it cost to fix OBD2 codes?

Repair costs vary widely by code, from $50 for a loose gas cap to $3,000+ for catalytic converter replacement. Common repairs like O2 sensors run $200-500, while transmission codes can exceed $2,500. Always get a proper diagnosis before authorizing repairs.

OBD2 Fault Codes & Dashboard Warning Lights

35 diagnostic trouble codes with repair estimates and 13 warning lights with urgency guidance. Free. No app required.

🚗 Can I Still Drive With This Light On?

Search any warning light or code to get a clear answer — STOP · CAUTION · OK TO DRIVE

35OBD2 Codes

13Warning Lights

68Symptoms

SAE J1979Standard Certified

NHTSAFMVSS 101

🔧 OBD2 Fault Codes

Look up any OBD2 diagnostic trouble code. Get symptoms, common causes, diagnostic steps, real repair cost estimates, and a clear answer to "Can I still drive?"

B0001 — Driver Frontal Airbag Squib Circuit Repair: $200-$800 B0028 — Right Front Side Airbag Deployment Loop Resistance Low Repair: $150-$600 C0040 — Right Front Wheel Speed Sensor Circuit Repair: $100-$400 C1201 — ABS Pump Motor Circuit Malfunction Repair: $200-$1200 P0101 — Mass Air Flow (MAF) Sensor Circuit Range/Performance Repair: $80-$400 Browse all 35 codes →

⚠️ Dashboard Warning Lights

What does that light on your dashboard mean? Identify by color and shape. Get clear urgency levels and step-by-step action guides.

Check Soon Abs Warning Light Amber Circle with ABS text and parentheses Check Soon Adblue Warning Light Amber Liquid droplet or UREA text Check Soon Airbag Warning Light Red Person seated with a deployed airbag circle in front Stop Soon (you have limited range) Battery Charge Light Red Battery icon with + and - terminals Stop Immediately Brake Warning Light Red Circle with exclamation point or the word BRAKE Browse all 13 lights →

🔍 Search by Symptom

Not sure what code you have? Find it by what your car is doing — engine shaking, check engine light, fuel smell, rough idle.

All 68 symptoms →

🔬 Our Diagnostic Methodology

STEP 1

Data Source

OEM service manuals, SAE J1979 standards

STEP 2

Verification

Cross-referenced with manufacturer TSBs

STEP 3

Update Cycle

Quarterly review with latest TSB data

STEP 4

Standards

SAE J1979, NHTSA FMVSS 101 compliance

📋 Data Sources & Standards

SAE J1979 / J2012 Standards
NHTSA FMVSS 101
OEM Service Manuals (Toyota, Honda, Ford, GM, etc.)
Manufacturer Technical Service Bulletins (TSBs)