Error code
W4 — Warning: SLI code missing
Missing location warning
The claim was processed, but it had no service location indicator, the three-letter code for where the service was provided.
What to do: Check the amount paid, then set the location indicator in your billing software so future claims carry it.
- Code
- W4
- Description
- Warning: SLI code missing
Explanation
Updated October 26, 2026
W4 is a warning that the claim had no service location indicator (SLI). Add the SLI on future claims where one applies.
What it means
Code W4 is a warning on the Remittance Advice (RA): the claim had no service location indicator (SLI). The SLI is a three-letter code that tells OHIP where the service was provided.
As a warning, it appears on a processed claim. Where an SLI is required, a missing one rejects on the Error Report instead (V64).
Common causes
- The SLI field was left blank in the billing software
- No default SLI set for the location
How to fix it
- Check the amount paid on the line.
- Set the SLI in your billing software so future claims carry it.
- If you believe the payment is wrong, send a Remittance Advice Inquiry (RAI) through eSubmit, or on form 0918-84, within 7 months of the RA date, with supporting details.
Don't resubmit if
- You disagree with how a claim already on the RA was paid. Use an RAI, not a new claim.
How APEX handles it
APEX reads your error reports and remittance advice from MCEDT and lists claims rejected with this code in its Correction Centre for you to correct and resubmit. See how APEX works · Pricing