Enter any OBD-II DTC code. Get a probability-ranked list of likely causes, real parts pricing, and the most likely fix — in under five seconds. Built for professional technicians.
Every DTC returns a weighted list of likely causes, sorted by real-world repair frequency and vehicle-specific data. Top result first — no more guessing which of ten possibilities it is.
Every listed part links to live pricing from AutoZone, O'Reilly, RockAuto, Amazon, and distributors worldwide. See availability in your region. Order in one click.
OBD-II passenger vehicles, medium-duty trucks, Class 4-8 commercial trucks, and heavy equipment. One interface, every system in your shop.
Each ranked part shows a percentage derived from millions of real repair records — not guesswork. When a tech walks into a job, they know what to check first.
A P0420 means the catalytic efficiency dropped. Great. But is it the converter, the O2 sensors, an exhaust leak, or a wiring issue? Every tool gives you the same list of five possibilities and leaves you to figure out which one.
PartRank uses repair record data from hundreds of thousands of jobs to rank those possibilities by likelihood. P0420 on a 2012 Honda? 73% it's the converter. P0420 on a 2018 Ram? The O2 sensors lead at 41%.
P0420 means the catalytic converter's efficiency has dropped below the EPA threshold. The most common cause is a failing catalytic converter — but not always. PartRank shows the exact probability breakdown for your vehicle: 73% catalytic converter, 18% post-cat O2 sensor, 7% pre-cat O2 sensor, 2% exhaust leak, less than 1% fuel system issues. Know what to check first.
We analyze millions of real-world repair records from shops worldwide. Every DTC gets a probability-weighted ranking specific to your vehicle year, make, and model. P0420 on a 2012 Honda? 73% converter. P0420 on a 2018 Ram? O2 sensors lead at 41%. Not a generic list — your vehicle's actual likelihood.
Yes. OBD-II passenger vehicles (1996–present, all makes), medium-duty trucks (Class 1-3), heavy commercial trucks (Class 4-8, J1939 protocol), and heavy equipment (off-road, agricultural, construction machinery). One interface, every system in your shop.
Every ranked part links to live pricing from AutoZone, O'Reilly, RockAuto, Amazon, and 50+ global distributors. See availability in your region and order in one click from the diagnostic result. No more calling around for parts.
All plans include a 3-day free trial. Start diagnosing immediately. Cancel before the trial ends and you won't be charged.
PartRank indexes 5,400+ OBD-II codes across all vehicle systems — powertrain, chassis, body, and network. Coverage spans emission-related codes (P04xx), engine codes (P03xx), transmission, ABS, SRS, and more.
PartRank turns one DTC into a ranked diagnosis, real parts pricing, and a path to the fix — in under five seconds. 3-day free trial, no credit card required.
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