Lexmex

P1346 is a VVT Sensor issue (bank 1) and P1351 is same error but bank 2, and they relate to a timing belt issue (skipping the teeth of the belt or a stretched belt).

UNOHOO

iTrader: (3)

so i may be in for a timing belt change huh? it probably is about due, i havent done it and ive put roughly 60k miles on it since i bought it.......#@$%!!

lol

Lexmex

How many miles on it now?

salimshah

You can clear the code and then give it a try and see if you get a CEL (you can do a read before CEL lights up ... you can get some pending codes).

I am not sure what the codes you read relate to ... lets go with the assumption that it is misfire. Reality check .. if the ecu reports it is a misfire then the problem is in the source or the sending unit (sensor) or the ecu has a problem. So take your pick but you should not tinker with what the ecu is trying to adjust.

While a backfire is hard to ignore, a misfire on a v6 manifests as fluctuating idle rpm.

My advice is still fix the source of the CEL and then improve other items.

Salim

UNOHOO

iTrader: (3)

not sure how many miles are on the belt now, i bought the car at roughly 160k miles from my mom, it has 218k miles on it now, she said she replaced it some time before i bought it but she doesnt remember how long before i bought it

blueridge

Assuming it was originally changed by Lexus at 90K, or another shop who put a quality belt on.....You would have 128K on this belt. Very much due if it's a quality belt...Way over if it's a cheap belt.

UNOHOO

iTrader: (3)

Well, looks like Lexmex wins the prize.

Got all my belts done today at the toyota dealership while i was at the dentist gettin a root canal. When i picked it up they had reset the ecu and the CEL was no longer on. Before when i would get it turned off it would come back on in like 15 miles or so. So far ive driven about 30 miles or so and no codes. The idle is still a little rough but not like it was. Not sure if that idle thing is completely gone but im cautiously optomistic

code58

UNOHOO- The rough idle probably isn't the IACV, but there is a way to check it. If you have an ohm meter, disconnect the plug to it and with the+ on the center of the 3 terminals, with the - check the ohms on each of the other 2. They should read AROUND 17-25 ohms each. When I cleaned my DIL's (took it off to do it) it read 59 ohms on 1 side and 0 ohms on the other side. Interestingly, it idled fine when I put it back on, but I don't know why. I did replace it. It is an electromagnet that rotates the round valve. There are other tests you can do on it and the plug as well to prove it's condition.

artbuc

Let me tell you what I ran into with my IACV. The Lexus repair manual is incorrect when it comes to the IACV electrical specs. They are for a different style (eg the one I have in my 99 Avalon V6). The IACV valve in my wife's RX is a digital pulse type which cannot be checked with an ohmeter. I did the checks on my wife's car according to the Lexus repair manual and concluded I needed a new IACV valve and bought one from Lexus. The new one had the same resistance reading as the old one so I called Lexus. After several phone calls I talked with a corporate technician. He confirmed the manual was wrong and that the IACV could not be checked with a VOM. Lexus reimbursed me for the new IACV!

UNOHOO

iTrader: (3)

right on thats a damn good idea, since you did replace yours, how much was it approx? I have a brand new throttle position sensor as well to throw on there, im thinkin that may clear some of this up too if that is somewhat faulty. Ive tried on several occasions to get that damn thing off but it looks like im gonna have to follow Lexmex's throttle body removal DIY to get to it. Anyway I'll pick up a multi meter and give that a shot. Thanks for the advice man

artbuc

If you have the IACV that I have you can not check it with a multimeter.

code58

Artbuc- Does your wife have the 99RX that is in your profile? What was the reason that you were going to change the IACV? Was it just because it didn't test what the Lexus shop manual stated? Had you cleaned it and it worked properly? The new one I put on did have the approximate proper values. Is there a way to check the IACV if it is the digital pulse type? I am puzzled by all this. Always wanting to learn....
Thanks for the input, Roger

artbuc

Roger, I am talking about my wife's 99 RX300. It has the same engine as my 99 Avalon except the RX has variable timing. The ECM controls movement of the Avalon IACV by alternatively applying a 250Hz duty cylce to the two coils in the IACV. One coil is for low duty cycle (closes IACV) and the other coil is high duty cycle (opens IACV). By varying the duty ratio (on time compared to off time) the change in magnetic field causes the valve to rotate. The Lexus Repair Manual incorrectly describes the Avalon IACV. The Avalon IACV coil resistances are exactly what the Lexus Repair Manual called for.

RX was running rough so I thought I would try cleaning the IACV. Pulled it off and did the electrical checks per the Lexus Repair Manual. Numbers were way off so I bought a new one as instructed to do by the Repair Manual. When I checked the new out of the box Lexus IACV the numbers were exactly the same as my old one. I was puzzled but installed the new IACV anyway. No change in engine performance. Lexus corporate confirmed that the RX IACV cannot be bench tested. Static resistance readings mean nothing. Apparently the RX ECM controls the IACV with a digital pulse modulation vs the Avalon type with a constant 250 Hz cycle alternating between two coils.

I solved the rough engine idle by cleaning the MAF.

PS. The RX IACV does open/close when you apply 12VDC as described in the Lexus Repair Manual.