Already have an OBD2 adapter?

Put it to work before you replace another part.

Connect the scanner you already own. ScanWrench reads what your car reports, explains it clearly, and shows the cheapest useful test to run next.

Check my adapter first

Download ScanWrench

3 free scans · no card required

No ScanWrench hardware purchase. No account or card required for the free path. The app checks the exact connection before describing coverage.

Bring your own adapter3 free scansNo account required

Current premium ScanWrench iPhone Scan screen, captured from the production app code

One scan. A clearer next move.

Scan your car

See what the car returned, what it could mean, and the first useful check—without turning one code into a parts verdict.

Your carConnect your scanner to get started

Scan my car

Usually 15–30 secondsPrivate · Plain English

Signals · Current vehicle intelligenceWhat changed around your car?

Recall campaigns, manufacturer updates, and clearly labeled public report patterns.

What do you want to check?

Choose what brought you here. ScanWrench keeps the next step focused.

Warning lightRead the code and see what to test next.Hybrid batteryCheck balance and temperature on supported cars.Used carLook for faults, resets, and missing checks.Verify a repairCompare the evidence from before and after.

Latest answers

What the warning means. What to check next.

Plain-language answers for warning lights, codes, inspections, used cars, and adapters.

Browse all answers

Access Truth8 min

Can an OBD2 scanner reset the oil or maintenance light?

Usually not through generic OBD2. Oil-life and maintenance resets are vehicle-specific; verify the exact function and reset only after service is complete.

Access Truth8 min

Can a regular OBD2 scanner clear ABS, airbag, or VSC codes?

A generic OBD2 clear does not universally erase ABS, SRS, or stability-control faults. Learn what exact enhanced access and repair verification require.

Buyer Brief8 min

Can an OBD2 scanner detect odometer rollback?

Sometimes a scan can reveal a mileage mismatch, but it cannot certify the odometer or prove fraud. Learn which records to compare before buying.

Interactive evidence

Watch the car build its own case.

One illustrative P0171 capture shows the difference between receiving a code and choosing the next useful test.

Stored codeP0171

STFT+18.7%

LTFT+14.1%

RPM731

Coolant194 F

Freeze frameCaptured

Next cheapest telling test

Check the intake path for unmetered air.

Elevated short-term and long-term fuel trim support testing for a vacuum or intake leak before condemning the catalytic converter or replacing a sensor.

Result is a cited hypothesis, not confirmed diagnosis.

Proof fingerprint7B8F 2A11 C09E 44D3

Illustrative demo data. No vehicle was connected for this example.

A vehicle owner checking ScanWrench beside a silver car — Choose your path
Start with the decision in front of you.
The evidence stays technical. The path changes based on what you need to decide.

Driver

My light is on

Separate urgent from expensive-looking.

See the evidence, the uncertainty, and the least expensive telling test before anyone starts replacing parts.

Follow the driver path

Buyer

I am buying a car

Ask for fresh evidence before the deal.

Challenge the vehicle, review readiness and fault memory, and keep a VIN-reduced decision record.

Follow the buyer path

Shop

I run a shop or fleet

Make the handoff easier to defend.

Capture before-and-after evidence, retain unchanged outcomes, and keep the technical record ready for the next person.

Follow the shop path Ask a fleet question

How it works

Connect. Capture. Decide.

A calm, direct workflow keeps hardware truth, vehicle evidence, and the next decision in the right order.

Connect

Measure the exact adapter, transport, and available command surface before describing coverage.

P0171+18.7%731 RPM

Capture

Record the returned codes, freeze frame, live context, readiness, and evidence gaps.

Evidence→Next test

Decide

Get a conservative test order and a privacy-reduced report with an integrity fingerprint.

Simple plans

Start free. Upgrade when the evidence earns it.

Prices are U.S. catalog references. Verified in-app storefront controls availability, localized pricing, tax, purchase, and restoration.

Free

$0/ month

The essential evidence workflow without an account or card.

1 vehicle
3 scans each month
10 saved sessions
Signed ScanReceipt

View desktop releases

Most popularPro

$9.99/ month

The complete owner and buyer intelligence workflow.

10 vehicles and unlimited scans
Diagnostic Coach and Trace Lab
Buyer Challenge and deep Buyer Intel
Academy Premium

Review Pro

Shop or Founders?

Shop$49.99 / month

100 vehicles, unlimited scans, 10,000 sessions, technician handoffs, and Fleet Drift.

Review Shop

Founders Core$499.99 once

Permanent Core access. Recurring Academy, deep Buyer Intel, and continuing services remain separate.

Review Founders terms

5-second compatibility check

Works with the adapter you already own. We check it in 5 seconds.

Search your model for an instant preview. When you connect, ScanWrench confirms the adapter, connection, and data your car makes available before the scan begins.

Which adapter do you have?

Results appear as you type. A model name is a candidate. The exact unit earns the claim. This preview does not verify a physical unit; the app confirms your connection in 5 seconds.

Start typing a brand or model. ScanWrench checks the adapter, connection, and available data before your scan begins.

Compare what you get

More than a code. Know what to do next.

Compared using each company's official product information. A check means the feature is clearly offered; an X means we could not verify it.

ScanWrench workflow compared with FIXD, BlueDriver, and Carly official consumer product descriptions.
Workflow	ScanWrench	FIXD	BlueDriver	Carly
Tamper-proof scan report	Yes. Proof ID included	No. No named tamper-proof report	No. No named tamper-proof report	No. No named tamper-proof report
Find the exact replacement part	Yes. Exact manufacturer part-number search	No. Repair guidance only	No. Repair Reports only	No. Repair guidance only
Fresh test before buying a car	Yes. Buyer Challenge	No. Vehicle history is separate	No. No named fresh-test workflow	Yes. Used Car Check
Use the adapter you already own	Yes. 5-second compatibility check	No. FIXD Sensor required	No. BlueDriver sensor required	No. Carly scanner required for most features

Official sources:FIXD BlueDriver Carly Read the Android OBD2 app buyer's guide

Clear answers

Before you connect.

The limits stay visible because the evidence has to hold up.

Do I need a ScanWrench adapter?

No. ScanWrench uses compatible customer-supplied adapter candidates and checks the exact unit at connection. A model name is a candidate, not a guarantee.

Does one adapter scan every module?

No. Generic OBD, manufacturer-enhanced data, full-system access, read-only functions, and state-changing functions are separate capability levels. ScanWrench reports only the level supported by the exact configuration.

Does ScanWrench identify the broken part?

No. ScanWrench preserves observed evidence and offers cited hypotheses plus the next safest test. A code alone does not prove which part failed.

Can I use ScanWrench without an account?

Yes. Choose Device Only to retain data on your device or Save Nothing to erase the session. An account is optional for supported cloud features.

Which desktop version is available?

ScanWrench Desktop 0.5.1 is available for Apple silicon Mac. Version 0.6.0 is available for Linux x64 and Linux ARM64. Windows remains unavailable until its exact Authenticode-signed installer passes the release gates.

Can I buy on this website?

No. The verified in-app storefront controls availability, localized pricing, tax, purchase, and restoration. Free remains available without a website checkout.

Use ScanWrench now

Start on iPhone or Android.

Download the public mobile app from Apple or Google Play, or use a signed desktop release. Windows stays behind its exact Authenticode release gates.

Public release

ScanWrench for iPhone

Bring a compatible OBD2 scanner. Read your check-engine code and see the cheapest useful test to run next.

3 free scans. No account required.