2009 Prius Check Engine Light On

The code readers used at car parts stores only read the P0xxx codes, not the higher codes like the P1xxx, P2xxx or higher. The code should be stored for about 10 drive cycles after the CEL goes out.

The saga continues but I think I finally have the cause of the problem. The CEL came on again this morning and I was not surprised. Yesterday my wife filled the gas tank up. I opened up the gas port and tightened down the cap. After 4 start/stop cycles (not all in a row mind you - but a start, drive, stop routine) the CEL turned off (just as I was heading to the auto parts store to get the OBD code read). This is the same thing I did last time - tightened the gas cap, had 3 or 4 start/stop cycles and then the CEL cleared. I still want to get the codes read (not just the P0XXX codes but the higher ones as well) but it’s starting to point to a new gas cap as the more complete fix to this problem. I’ve heard that others have had similar experiences when their gas caps started wearing out.

I’d get a Toyota cap.

The code, P1121, is unique to Prius cars. Read and learn. If the light returns, take it to a Dealer…

I replaced my gas caps twice, first time with a generic one and the last time with a Toyota one. None worked for me. Let me know if anyone’s new gas cap works.

I had 5 codes come up one of which was 1121. I replaced the Part Number 16670-21010 on my 2005 Prius in the link above bought from parts.autonationtoyotagulffreeway.com.

I unplugged the battery during repairs and none of the codes have come back up. I did it over the weekend. You should be able to find priuschat instructions on how to replace the valve. I would add taking off the bumper and driver headlight would make the job easier. Still waiting on the gas mileage to come back up to normal.

Hey guys,

Sister’s mechanic replaced my charcoal canister and that got rid of my 0446 code for good.