Hey guys, I have a manual is300 187k on the clock. Had major service done in 179k miles including timing belt change. things were doing great for about 2 years and 7k miles. then I had the occational engine stumbling like misfires and engine light came on. code pulled was P1346 and I decided to straight up change the OCV and new filter. replaced it without issue and car no longer stumbles and drives very smoothly. However, I keep getting the same engine code. it takes some time to trigger it, a few drives but it always comes back. other than the light I dont see any other issues. Only thing I had done recently was installing an exhaust silencer that had an 1.5" opening. It seemed too restrictive so I switched to 2.5" adjustable silencer to my OBX 4.5" exhaust. due to this code, I decided to remove it all together to remove possible excessive back pressure. the code still remains after having it cleared 3 times now.

Last time I got it cleared by my buddy, he also had the toyota diagnostics. He noted that the OCV is working and it stalled my car when activated. He revved the car up to try to induce the code but it never came up. Since I have no other codes, I am reluctant to replace other sensors. Is my ECU the next culprit and maybe I should send it off to be checked by SIA electronics? is there a sensor that might not be throwing a code but messing with my signals or is my timing belt stretched in only 7k but excessive back pressure from my silencer did the trick?

Any help would be great to diagnose and fix the problem. thanks!

 

Make sure the connector is good shape. Did you do a hard rest of the ECU? (Remove cable from battery)

 

I have not removed battery and do hard reset before. connector seems good still. Perhaps I will use deoxit on the connector to the OCV, and do a hard reset when I get a chance today.

Edit: so I hard reset with battery cable dissconnect. used deoxit on the connector. still came back in 2 drives. next I took off the upper timing cover and I will try to see if the timing is lined up properly. Not sure how I can do that, but I will check it out. If the timing is not off, whats next?

 

Is your VVTI gear in good working order?

 

After taking out the top timing cover, I see the timing is off by 1 tooth on the VVTI to exhaust timing gear. I did not check with the crank timing just yet. I also see some oil around the VVTI cam gear area, so I think it means my VVTI is failing / leaking. interesting to think a leaking VVTI gear would throw the timing off by 1 tooth. or is the belt simply jumped a tooth and 2 separate problems here

 

Not likely. Rebuild the gear and redo the timing. If the cam seals are old. Do those while in there.

 

So it looks like my p1346 code was due to my vvti timing gear jammed and doesn’t turn freely like it should according to my mechanic. It then stretched my timing belt and caused it to be off by 1 tooth. So it needed a new vvti gear, belt, and also found my harmonic balancer was starting to separate. All in all a lesson Ed learned to replace the vvti gear with timing belt in the future especially if it hasn’t been done before and all is300s are now going on almost 20 years and going towards 200k miles