Scan tools by the numbers
What your money buys, what drivers actually run into, and where car diagnostics is heading – worked out from public data and our own research, with every source named.
What do drivers complain about?
Every vehicle safety complaint filed with the federal government, searched for warning lights, the systems involved and the trouble codes drivers quote.
How to read it: the share of complaints naming each system. One complaint can name several, so the bars add up to more than 100%.
What it means: engine and electrical problems lead, with airbags and the powertrain close behind. Airbags, steering, brakes and much of the electrical system are out of reach for a basic engine-code reader – the gap a multi-system scanner fills.
How to read it: the share of all complaints whose description mentions each light (simple text matching, so treat these as close estimates).
What it means: the check engine light is mentioned far more than any other. A warning light is when most people reach for a scanner – and the airbag and ABS lights need a tool that reads those systems. See ABS, Airbag and Transmission Codes.
How to read it: complaints quoting each code, counted once per complaint, with the brands whose owners quote it most.
What it means: the list splits in two. Some codes come almost entirely from one brand’s owners – P1326 is Kia and Hyundai’s engine knock-detection warning, C1391 is Toyota and Lexus, C0020 is RAM – which points to known problems with particular models. The misfire codes (P0300–P0304) and P0420 (catalytic converter) turn up across many makes: the everyday codes any scanner reads. More in OBD2 Explained.
How to read it: of all the codes quoted, the share starting with each letter.
What it means: everything that isn’t a P code needs a scanner that reads beyond the engine.
How to read it: for each model year, the percentage of complaints about those vehicles that name the electrical system. Years with too few complaints are left out.
What it means: the share climbs with newer model years – more electronics, more electrical complaints. Read the direction, not the exact level: the newest model years have had the least time to collect complaints.
Source: NHTSA Office of Defects Investigation – vehicle complaints flat file (FLAT_CMPL.zip). Complaints are reports owners chose to file about safety problems, so they lean toward serious failures – they show what safety complaints look like, not how often cars break.
Are cars becoming computers?
Recalls are the problems carmakers themselves agree are safety defects. More and more of them are about software – and a growing number are fixed without a trip to the dealer.
How to read it: each column is one year: the percentage of that year’s vehicle recalls whose defect or fix mentions software, reprogramming or recalibration.
What it means: software went from a rare recall cause to roughly one recall in five – the manufacturers’ own version of the electrical trend in owner complaints above. More of what goes wrong now lives in code and electronics, which is why a scanner that reads every module matters more than it used to. See What Is a Bidirectional Scan Tool?
How to read it: the number of vehicle recalls each year whose fix can be sent wirelessly to the car.
What it means: almost none before 2020, then a sharp rise. Good news for owners – and another sign of how much of a modern car is software.
Source: NHTSA Office of Defects Investigation – vehicle recalls flat files (FLAT_RCL_PRE_2010 / POST_2010). Counts are recall campaigns (one recall can cover many models). NHTSA’s vehicle category also includes motorcycles, RVs and heavy trucks. Recall counts aren’t a quality ranking – a maker that recalls quickly can look worse than one that doesn’t.
What does your money buy?
Scanners run from about $20 to $500. Here’s which capabilities each price band gets you, across the 12 tools we review.
| Price band | Reads ABS codes | Reads airbag codes | Runs active tests | Free updates for life |
|---|---|---|---|---|
| Under $503 tools | 0% | 0% | 0% | 67% |
| $50–$1001 tool | 100% | 100% | 100% | 0% |
| $100–$2005 tools | 100% | 80% | 0% | 100% |
| $300–$5003 tools | 100% | 100% | 100% | 67% |
How to read it: each row is a price band; each cell is the share of tools in that band with the capability. Bands are based on the middle of each tool’s typical price. With only a few tools per band, one tool moves a cell a lot.
What it means: under $50 buys engine codes only. The $100–$200 tools all read ABS codes and most read airbags too, but none run active tests. Active tests mostly start around $300 – the exception is the OBDeleven 3, in the $50–$100 band, which runs them on the brands it supports.
Compare all 12 scanners side by side → What are active tests? →
Source: ScanToolAdvisor's research on the 12 scanners it covers (data/scanners.csv). This is a hand-picked list of popular tools, not every scanner sold.
How these numbers are made
Each section comes from a Jupyter notebook that downloads the public data, cleans it, works out the numbers and saves them for this page – so every figure can be traced back to its source and re-run when new data comes out. Questions about the method? Get in touch.