All 20 OBD-II codes, sorted by system
The first letter of the code tells you which system stored it. P is powertrain. U is the network the computers talk on. Read the letter, then read the number.
Every row links to a full page: whether you can keep driving, how long you have, what the repair costs, and how to check the shop's story.
P codes — powertrain
Engine, transmission, and emissions. Most codes you will ever read start with P.
| Code | What it means | Severity | Shop price | Drive window |
|---|---|---|---|---|
| P0011 | Camshaft Position Timing Over-Advanced (Bank 1) | Caution | $200 – $900 | 3 months |
| P0016 | Crankshaft / Camshaft Position Correlation (Bank 1) | Stop driving | $300 – $1,500 | Park it |
| P0101 | Mass Air Flow Sensor Range / Performance | Caution | $150 – $500 | 6 months |
| P0113 | Intake Air Temperature Sensor Circuit High | Safe to drive | $100 – $250 | 12 months |
| P0118 | Engine Coolant Temperature Sensor Circuit High | Caution | $100 – $250 | 3 months |
| P0121 | Throttle Position Sensor Range / Performance | Caution | $200 – $600 | 2 months |
| P0128 | Coolant Thermostat Below Regulating Temperature | Caution | $150 – $400 | 6 months |
| P0135 | O2 Sensor Heater Circuit (Bank 1 Sensor 1) | Caution | $150 – $350 | 12 months |
| P0171 | System Too Lean (Bank 1) | Caution | $100 – $600 | 2 months |
| P0172 | System Too Rich (Bank 1) | Caution | $100 – $650 | 1 month |
| P0300 | Random or Multiple Cylinder Misfire Detected | Stop driving | $120 – $900 | 2 weeks |
| P0301 | Cylinder 1 Misfire Detected | Stop driving | $120 – $700 | 2 weeks |
| P0335 | Crankshaft Position Sensor A Circuit | Stop driving | $150 – $400 | 2 weeks |
| P0420 | Catalyst System Efficiency Below Threshold (Bank 1) | Caution | $180 – $1,200 | 3 months |
| P0430 | Catalyst System Efficiency Below Threshold (Bank 2) | Caution | $180 – $1,200 | 3 months |
| P0442 | Evaporative Emission System Leak Detected (Small Leak) | Safe to drive | $80 – $250 | 12 months |
| P0455 | Evaporative Emission System Leak Detected (Large Leak) | Safe to drive | $80 – $300 | 12 months |
| P0456 | Evaporative Emission System Leak Detected (Very Small Leak) | Safe to drive | $90 – $280 | 12 months |
| P0700 | Transmission Control System Malfunction | Caution | $100 – $3,000 | 2 months |
U codes — network
The computers talking to each other. When one goes quiet, the car can stop dead.
| Code | What it means | Severity | Shop price | Drive window |
|---|---|---|---|---|
| U0100 | Lost Communication With ECM/PCM | Stop driving | $100 – $1,500 | Park it |
How to read this list
- Severity is the drivability call, not how expensive the repair is. A cheap sensor can still be a stop-driving code.
- Shop price is parts plus labor at an independent shop. Dealer quotes run higher. DIY parts-only ranges sit on each code page.
- Drive window is an estimate, and it assumes the conditions on the code page stay true. Nobody can give you an exact number from behind a screen.