Tight cap with DTC

June 2, 2014

Owners of 2012 Acura TL 2WD vehicles may complain that the “TIGHTEN FUEL CAP” message appears in the MID (multi-information display), but the technician ,may find no pending or confirmed DTC P0455 or P0456.

The probable cause is the PCM misinterpreting the purge air flow. The corrective action involves updating the PGM-FI software with the HDS using HDS software version 2.026.011 or later.

  1. Check the MID for messages. If there are messages, go to Step 2. If not, this TSB does not apply.
  2. Check for DTCs with the HDS. If DTCs are present, continue with normal troubleshooting. If no DTCs are present, follow the repair procedure.


  1. Use the HDS to clear PGM-FI DTCs.
  2. Update the PGM-FI software with the HDS.
  3. Delete the TIGHTEN FUEL CAP message in AcuraLink, if equipped.