OBD2 Code Lookup
Instant check engine light diagnosis — meaning, causes, fixes, and repair cost
Your check engine light just came on — before you pay $120 for a shop diagnostic, look up the OBD2 code yourself for free. Our database covers thousands of P, B, C, and U codes with plain-English descriptions, the most common causes, and fixes that actually work.
Every result includes a DIY difficulty rating and an estimated repair cost range so you know whether to grab a wrench or call your mechanic. You also get a "safe to drive?" verdict — because some codes are minor inconveniences while others mean pull over immediately.
How to Use the OBD2 Code Lookup
- 1 Plug an OBD2 scanner into the diagnostic port under your dashboard (usually below the steering column).
- 2 Read the code — it starts with P, B, C, or U followed by 4 digits (e.g. P0420).
- 3 Type or paste the code into the search box and click Look Up Code.
- 4 Review the diagnosis: description, common causes, recommended fixes, estimated repair cost, and safe-to-drive verdict.
P codes are powertrain (engine/transmission), B codes are body, C codes are chassis, U codes are network/communication. A second digit of 0 = generic OBD2 standard; 1 = manufacturer-specific.
Frequently Asked Questions
What is an OBD2 code?
OBD2 (On-Board Diagnostics II) is a standardized system built into all cars sold in the US after 1996. When the vehicle's computer detects a problem, it stores a Diagnostic Trouble Code (DTC) and illuminates the check engine light. These codes follow a universal format any OBD2 scanner can read.
Can I clear the check engine light myself?
Yes — any OBD2 scanner can clear the code. However, the light will return if the underlying problem isn't fixed. Clearing the code also resets your emissions readiness monitors, which can cause you to fail an emissions inspection for up to 100 drive-cycle miles afterward.
Is it safe to drive with the check engine light on?
It depends on the code. A steady yellow light usually means non-urgent — you can drive but should get it checked soon. A flashing check engine light indicates a severe misfire that can destroy your catalytic converter. Do not drive with a flashing check engine light.
How accurate are the repair cost estimates?
Estimates are based on national average labor and parts costs from industry data sources. Actual costs vary by region, labor rates, and OEM vs. aftermarket parts. Use our range as a benchmark when getting quotes from local shops.