Toyota Repair: 2001 Avalon Codes P1150,P1354, air fuel ratio, vvt system


Question
QUESTION: Hi Gary, 2001 Avalon 145,000 miles. Recently developed rough idle when warm. Today produced codes of P1150, P1354. It points to the VVT system. Can a DIY diagnose and repair from home?

Thanks,
John

ANSWER: The P1354 code is for the VVTi malfunction on bank2 which is the cylinder head near the firewall, the 1150 code is for the air.fuel ratio sensor on the same head, the VVTi code can cause the A/F ratio sensor to go out of range, the main cause is the P1354 code which should be delt with first, this can be caused by a worn timing belt that has junped a tooth on the sprocket, this should be checked first, at this mileage if it has never been replaced it may be the problem. If your scanner can read live data see where the engine timing is at.
If the timing is not the problem it may be a bad oil control valve for the VVTi system, to be sure it should be active tested using a diagnostic tool that is capable of doing so, activating the system at idle should cause the engine run rough at idle, if there is no effect on the engine the VVTi is not activated and the problem may be the OCV.

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QUESTION: Can this evaluation be handled by a competent local mechanic or at the dealership only?
Thanks
John

Answer
I'm sure there are technicians that are qualified to diagnose this at most larger repair facilities, I would call ahead and ask if the shop has ASE certified technicians, at least a couple, they should know how to deal with this. You can reply back to me and let me know what they recommend doing to fix this.
Don't just accept "we have to replace this or that" demand an explanation,preferably in form of a written estimate, let me know how it goes