i already posted this in the electronic section but thought maybe it belonged here more. I hope that isn't a problem didn't see anything about it in the rules.

98 4runner, v6.

So a while back my engine light came on and I took it into my mechanic. It gave the code p0505 for the idle control valve. So he cleaned up the valve door, (i guess), and cleaned the sensor and reset it. A few days later It came on again so i took it back into the shop and the took the idle control unit apart and cleaned the inside. He did find what looked like a single piece of dog food in there. covered in carbon. reset it again. The next day the light came on again. It seems to do it in the morning but if the truck warms up it doesn't come on. If i drive it enough to warm it up and let it sit parked for a few hours the light won;t come back on when i start it. It idles at about 1400 cold and 850 warm. (if the light is on). if not, 700 warm not sure what the cold is. I did have him replace my timing belt and water pump about 3 weeks before it started. not sure if that can be related though. If anyone has any good ideas i would appreciate them.

thanks
mike

 

Dont waste your time trying to clean it. Replace it

 

what exactly is the part that needs to be replaced? and if i replace it and it is still doing it. I would like to narrow down the possibilities before hand.

 

The IAC valve. IAC= Idle Air Control. Its attached to the underside of the throttle body. Im sure replacing it will cure your problem. You can get a used one at a wrecking yard or buy a new one from toyota

 

Here are details from a 97 Tacoma manual.

 

Agreed, replace the IAC Valve. The belt and service work performed are not of concern.

 

is this something i should buy from a toyota dealership? if so how much do they run? I saw an acdelco one with a lifetime warranty for 180. If the problem is in the wiring would replacing the whole icv unit solve that?

 

Ahh! the water pump. Make sure that he burped the cooling system well. The IAC has two coolant lines to it. If the cooling system was not burped properly there could be an air pocket in the IAC or the IAC coolant lines causing problems. It could also set a code because the ECM may read operating temp, but sees the IAC doing something it shouldn't be, acting like a cold engine. This can keep the engine from going into closed loop, causing poor fuel milage and eratic RPM's. I have seen this several times on the 22R-E, but not so much the 3.0. Try removing the radiator cap when the engine is cold, turning the heat on and recirculate mode, wait for the thermostat to open and then re-install the cap. Thats what I would do before buying a new IAC valve and it's free.

 

That code won't set because of a low coolant issue. All it would do is idel funky with no code. The code is set because of the bad IAC itself. Get it from the dealer

 

The thing with the water pump.... after i got it back the coolant reservoir was full. Then when the light very first came on i checked all my fluid levels and the coolant reservoir was at the very bottom.. I put in more coolant and the light went off. but then since the light kept coming back later... now the coolant levels are fine i dismissed it. So could that be the problem??

I'm not a very mechanical so bear with me. If i want to try this i just remove the radiator cap. turn on my truck, turn on my heater with the recirculating mode on, and then how can i tell when the thermostat opens? and then put the cap back on while the truck is still running.

 

When the t-stat opens the lower radiator hose will start getting hot. You may also notice the extra flow if you have the rad cap off.

 

again, the low coolant wont throw that code. A bad ISC valve will

 

Yeah, I have completely bypassed the coolant line to the throttle body and haven't thrown a code.

 

does anyone know where i could get an oem part other than a dealership? from them they said it would cost 300. I'm sure there has to be somewhere online i could get one cheaper.

 

Here's one of my favorite online dealers (Bob Bridge Toyota, Renton , WA) Everytime I compare they have the best prices, and I've always gotten great service:
https://www.1sttoyotaparts.com/partscat.html

 

i don't see that they carry this part.

 

You may have to call, not everything is listed in that online catalog. When you call tell them you are an internet customer.