Dtc p0171 dtcp0174 need to update the pgm-fi software with the hds service bulletin 08-043
Multiple cars with same problems. http://tl.acurazine.com/forums/showthread.php?t=738498 tech line summary article if the ?tighten fuel cap? message is displayed on the mid but the vehicle passes the service manual troubleshooting, use the following procedure to check the evap canister purge valve: 1. run the engine at idle with the hood closed for 30 minutes 2. hold the throttle at 2,000 rpm and monitor ?evap pc duty? with the hds. 3. once the duty cycle reaches 90% or more, monitor the ftp sensor for 60 seconds 4. if the ftp sensor reading reads about 2.50 volts or if it fluctuates rapidly between about 2.3 volts and 2.5 volts install a known good evap canister purge valve 5. test-drive the vehicle for several minutes at highway speeds. if the fuel cap warning message stays off, replace the evap canister purge valve. if the warning message comes back on test the evap system for leaks. (vc-rt, sn, 7700). *tr