Fix a VIN that will not decode

What to check when a VIN won't decode, returns the wrong vehicle, or comes back empty — reading the VIN correctly, reusing a recent vehicle, and where to go next.

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This is the troubleshooting companion to a normal scan. If a VIN will not decode, comes back as the wrong vehicle, or returns nothing, this article covers what to check and where to go next. For the step-by-step of a normal scan — typing the VIN, pressing Decode VIN, and confirming the vehicle banner — read Scan a VIN with YardScan first. If you are tearing one vehicle down into many parts, see Part out a whole vehicle.

> [!NOTE] > The VIN step is a typed 17-character field, not a camera or barcode scan. Almost every "won't decode" problem comes down to one mistyped character, so most of this article is about reading the VIN correctly.

What the VIN box accepts

The field is labelled Vehicle Identification Number and shows a live counter — {vin.length} / 17 — as you type. It enforces the format for you:

  • It keeps only the characters a VIN can contain: the letters A–H, J–N, P–R and S–Z, and the digits 0–9. That range technically lets a Q through, even though a real VIN never uses one — more on that below.
  • It removes anything else the moment you type it — spaces, dashes, and the letters I and O are stripped automatically, and everything is uppercased. A pasted VIN with spaces or hyphens is cleaned the same way. Q is the exception: it is not stripped, so you can type it, but because a VIN never contains Q the field flags it as invalid once you reach 17 characters — see the error table below.
  • At exactly 17 valid characters the field turns green, shows a Valid pill, and the status line reads Ready to decode. Below 17 it counts down (for example, 5 characters remaining).
  • Decode VIN stays disabled until the VIN is exactly 17 valid characters. You cannot decode a malformed VIN — the button will not respond until the field is complete and valid. While a decode is running the button shows a spinner and reads Decoding….

The field also carries a permanent note beneath it:

> VIN excludes the letters I, O, and Q to avoid confusion with digits.

> [!NOTE] > The inline check under the box only confirms the length and the I/O/Q rule. It does not confirm the VIN is real or complete. A VIN can be 17 valid characters and still fail to decode — that failure appears in a red banner at the top of the page, not inline.

Look-alike characters to double-check

Because I, O and Q are never part of a VIN, any character on the plate that looks like one is really a digit. This is the most common cause of a decode that "won't work" despite a VIN that looks right.

| On the plate it looks like… | In a VIN it is actually… | |---|---| | The letter O | the digit 0 (zero) | | The letter I | the digit 1 (one) | | The letter Q | never valid — re-read it; it is most often the digit 0 |

Faded or dirty plates also blur other pairs — a 5 and an S, an 8 and a B, a 2 and a Z. When a decode fails, read the VIN slowly, one character at a time, against a clean source.

If the dashboard plate is hard to read, the VIN also appears in these places:

  1. Driver's-side dashboard, visible through the windshield
  2. Driver's-side door jamb sticker
  3. Vehicle title or registration
  4. Insurance card or policy

When the VIN won't decode

There are two separate places a VIN problem shows up. The inline status line under the box handles format only (length and the I/O/Q rule). The red banner at the top of the page appears when a format-valid VIN is sent to be decoded and comes back without a vehicle; dismiss it with the X, or it clears the moment you press Decode VIN again (or use Change vehicle).

| On-screen text | Why it appears | What to do | |---|---|---| | VIN must be 17 characters (currently {n}) | The VIN is not exactly 17 characters. | Count again against the plate; add the missing characters or remove extras until the counter reads 17 / 17. | | VIN cannot contain I, O, or Q | A Q reached 17 characters. The box strips I and O as you type but lets Q through, then flags it. | Re-read that position on the plate: a character that looks like Q is almost always the digit 0. Replace it and the error clears. | | A decode-failure message in the red banner | The VIN passed the format checks, but the decoder did not return a vehicle for it. The banner shows the reason returned by the decoder; if none is given it reads Failed to decode VIN. | Re-check the VIN character by character for a misread look-alike, correct it, and press Decode VIN again. If the VIN is definitely correct, see *Where to go next* below. | | Not authenticated | Your session has expired or you are signed out. | Sign in again, then return to YardScan and decode. |

> [!NOTE] > GridX Connect does not display which vehicles the decoder covers. If a VIN you have double-checked as correct still will not decode, the vehicle may sit outside what the decoder can identify. That is not something you can fix by re-typing — go to *Where to go next*.

If you scanned this vehicle before

If this VIN has been decoded before, you do not need to decode it again. When the VIN box is empty, the right-hand column shows Recent vehicles — the last 10 vehicles you have worked on, each with its year/make/model, a masked VIN (for example 1HGB…1234), and how many parts you scanned off it.

  1. Clear the VIN box completely — the Recent vehicles list only appears while the box is empty.
  2. Find the vehicle in the list.
  3. Click its row.

You go straight to the part step using the stored vehicle details, with no decode call at all. This is the reliable way past a decode that is misbehaving for a vehicle you have used before.

> [!TIP] > Recent vehicles disappears the instant you type a character. If the list vanished, delete what you typed to bring it back.

If the wrong vehicle came back

Once a VIN decodes, the vehicle banner appears above the part steps with the year/make/model, its spec pills, and the full VIN. You cannot edit a decoded vehicle in place — to correct it you start over with a corrected VIN:

  1. In the vehicle banner, press Change vehicle →. This resets the form to a blank VIN entry.
  2. Type the corrected VIN.
  3. Press Decode VIN and confirm the new banner before continuing.

If you only stepped forward and used Back, re-editing the VIN there also works — any edit to the VIN clears the previously decoded vehicle so your next decode starts clean.

About the "Quick question" prompt

Decoding a VIN takes you straight to a single vehicle banner — there is no "choose one of these matches" step at the VIN box.

You may instead see a Quick question prompt later, after you move on and press Identify part. It appears when the part you are scanning needs one more detail to be pinned down (for example, choosing between engine or trim options). To handle it:

  1. Read the question and the options offered.
  2. Choose the option that matches the vehicle. You may be asked a second, follow-up question — answer each in turn.
  3. If you cannot answer, press Cancel. YardScan returns you to the part step and shows Part identification cancelled.

Quick question narrows the part identification when one more detail is needed — it does not change or correct the vehicle that already decoded. If the vehicle itself is wrong, use Change vehicle and re-decode.

Where to go next

  • A valid VIN still will not decode. If you have confirmed the VIN character by character and it genuinely will not decode, contact support — the vehicle may fall outside what the decoder covers, which is not something the app shows on screen. See Get help and contact support.
  • You are stripping a whole car. For decoding one VIN and scanning many parts off it, see Part out a whole vehicle.
  • You want the normal walkthrough. For the standard scan from VIN to published part, see Scan a VIN with YardScan.