These are errors and rejects every filer can get when sending information returns to IRIS, whether through the free IRIS Taxpayer Portal or through filing software. IRIS reports each one on the acknowledgment by rule number.
Form 1098-C business rules
Besides the rules on this page, IRIS checks the rules every form shares, such as SHAREDIRFORM014 (payee name and TIN); those are on the cross-form error code pages. The IRIS Taxpayer Portal also takes Form 1098-C as a CSV upload, using the IRS template for the form.
In the tax year 2026 rule set: 2 report error and reject over the threshold, 3 report error. A reject stops the submission; a report error is accepted with errors and counts as filed; past an unpublished threshold, report errors reject the submission. The descriptions are our own summaries; your acknowledgment gives the rule number.
| Rule | Severity | What it checks |
|---|---|---|
| F1098C001 | Report error | If the vehicle sold for more than $500, the box certifying a sale to an unrelated party must be checked and the date of sale given. |
| F1098C002_001 | Report error | If goods or services were provided in exchange for the vehicle, their value and description are required. |
| F1098C003 | Report error, reject over threshold | Only one of the two goods-or-services boxes (yes or no) can be checked. |
| F1098C004 | Report error, reject over threshold | The vehicle identification number (or other ID) is required. |
| F1098C005 | Report error | If the box for a vehicle deduction limited to the specified amount is checked, the form should not be filed with the IRS. |
Elements of Form1098CDetail
Each Form 1098-C return is one Form1098CDetail record in a submission of group 1. The table lists its 26 elements in schema order for tax year 2026: whether each is required, and the format IRIS accepts. Element names are the ones the IRS uses in its IRIS ATS examples and Publication 5718; the IRS revises the schema each year. A FIRE filer converting a Pub 1220 file finds the field-by-field mapping in the Pub 1220 to IRIS crosswalk.
| Element | Required | Format |
|---|---|---|
TaxYr | Required | Four-digit year |
RecordId | Required | Whole number, up to 8 digits |
IssuerOfficeCd | Optional | Exactly 4 characters |
VoidInd | Required | 1 (yes) or 0 (no) |
CorrectedInd | Required | 1 (yes) or 0 (no) |
PrevSubmittedRecRecipientGrp | Optional | Group of elements |
RecipientDetail | Required | Group of elements |
RecipientAccountNum | Optional | Text, up to 30 characters |
ContributionDt | Required | Date, YYYY-MM-DD |
OdometerMileageQty | Optional | Whole number, zero or more |
VehicleModelYr | Optional | Four-digit year |
VehicleMakeNameTxt | Optional | Text, up to 20 characters |
VehicleModelNameTxt | Optional | Text, up to 25 characters |
VINOrOtherIdNum | Optional | Text, up to 25 characters |
CertifiesVehSoldToUnrltPrtyInd | Required | 1 (yes) or 0 (no) |
SaleDt | Optional | Date, YYYY-MM-DD |
GrossProceedsFromSaleOfVehAmt | Optional | Amount, zero or more, up to 2 decimal places |
CertifiesVehicleNotTrnsfrInd | Required | 1 (yes) or 0 (no) |
CertifiesVehTrnsfrToNeedyInd | Required | 1 (yes) or 0 (no) |
CertifiesDetailedImprvDesc | Optional | Text, up to 1000 characters |
GoodsAndServicesYesInd | Required | 1 (yes) or 0 (no) |
GoodsAndServicesNoInd | Required | 1 (yes) or 0 (no) |
ValueOfGoodsAndSrvcForVehAmt | Optional | Amount, zero or more, up to 2 decimal places |
GoodsAndServicesDesc | Optional | Text, up to 1000 characters |
IntangibleReligiousBenefitsInd | Required | 1 (yes) or 0 (no) |
VehClaimDedUnderSpcfdAmtInd | Required | 1 (yes) or 0 (no) |
Check a file before you send it. TIN Comply's free IRIS 1099 File Checker runs an IRIS XML or CSV file against the IRS business rules in your browser.