Twenty-two times the price. Almost the same data.
Seven scanners, one fault, one car. Car and Driver made the fault rather than waiting for it — unplugging the mass-air-flow sensor on a 2005 Corolla until the light came on — then plugged each scanner into the same car and counted what it could actually read.
Twenty-two times the price, the same data
Live data channels, or parameter IDs, are what this category is compared on: how many things about the running engine the tool can show you at once. Here is how that count moves across a price range of 22 to 1.
We do not print prices — they go stale, and the retailer’s own page is where the current one lives. The tiers below are ours, assigned from the prices Car and Driver listed at the time of the test: budget, mid, upper, premium, spanning the 22-to-1 range in that order. They are a comparison made on that day, not a statement about what anything costs now.
Scale runs to 21 PIDs, the highest measured value here.
use it Car and Driver, Best OBD-II Scanners, Tested, November 2025. A fault was manufactured rather than waited for: the mass-air-flow sensor was unplugged on a 2005 Toyota Corolla until the check-engine light was confirmed, then every scanner was plugged into the same car and the same fault. Counted per unit: live-data parameter IDs, freeze-frame IDs, inspection and maintenance monitors shown, and the time from plug-in to a code on screen. Professional-grade tools were deliberately excluded.
The cheapest tool reads 16 channels. The dearest reads 19. The one that reads the most — 21 — is a mid-tier tool, at about a seventh of what the premium unit costs. Run the correlation between price and channel count across the seven and it comes out at +0.16, which is to say there is essentially no relationship. That figure is our arithmetic over Car and Driver's counts; the counts are theirs and the sums are in the table below.
What you are actually paying for
So what does the premium tier buy? One thing, and it is not on most listings in plain language: bidirectional control. A read-only scanner tells you what the car thinks. A bidirectional one can command it — run the fuel pump, cycle an ABS valve, fire an injector — which is how you tell a failed part from a failed sensor reporting a healthy one.
Of the seven, exactly one is fully bidirectional and one is partly. Everything else reads. If you are pulling a code to know whether to worry, read-only is the whole job and the budget tool does it. If you are diagnosing a fault to repair it yourself, that is the feature you are buying and the channel count is a distraction.
The one with a subscription
One unit in this test requires a subscription. It is the only one, it sits in the mid tier before that charge, and its channel count is 17 — one more than the budget tool, which in this test asked for no app, no account and no subscription at all.
A recurring charge on a tool you use twice a year is a different product from the one the price tag describes. It is worth checking on any scanner before buying, because it is rarely on the front of the box.
Seven scanners, as tested
| Product | Live data parameter IDs use it | Bidirectional commands the car use it | Connection as supplied use it | Where to buy |
|---|---|---|---|---|
| Gearwrench Everyday Diagnostic Tool our pick Mid tier. Most live channels of the seven, at a seventh of the dearest | 21 | Limited | Bluetooth | Check on Amazon |
| Foxwell NT301 Mid tier | 20 | No | Corded | Check on Amazon |
| Innova 5610 Premium tier, and the only fully bidirectional unit here | 19 | Yes | Corded / Bluetooth | Check on Amazon |
| Ancel BD310 Mid tier | 18 | No | Corded / Bluetooth | Check on Amazon |
| BlueDriver Pro Upper tier | 17 | No | Bluetooth | Check on Amazon |
| Fixd Mid tier, and requires a subscription — the only one that does | 17 | No | Bluetooth | Check on Amazon |
| Motopower MP69033 Budget tier. Cheapest here, and reads within three channels of the dearest | 16 | No | Corded | Check on Amazon |
use it Car and Driver, Best OBD-II Scanners, Tested, November 2025. A fault was manufactured rather than waited for: the mass-air-flow sensor was unplugged on a 2005 Toyota Corolla until the check-engine light was confirmed, then every scanner was plugged into the same car and the same fault. Counted per unit: live-data parameter IDs, freeze-frame IDs, inspection and maintenance monitors shown, and the time from plug-in to a code on screen. Professional-grade tools were deliberately excluded.
What nobody has measured
- Code coverage beyond the generic set. Every OBD-II tool reads the standard powertrain codes. Manufacturer-specific codes — the ones that actually name the part — vary hugely by tool and by car, and no published test compares them across brands.
- Whether the app still exists in five years. Every Bluetooth unit here depends on a phone app and an account. Nothing measures what happens when the company stops updating it, and a corded tool has no such dependency.
- Accuracy of the live figures. The counts are of how many channels appear, not of whether the numbers in them are right. No test we found put a known signal in and checked what came out.