Iac valve for 4.0 Tacoma

Where is the iac (idle air control) valve located on igrfe 4.0 engine?the engine idle is rough I cleaned the maf sensor so that was not the issue.

 

I'm not sure these trucks have an iac valve. have you cleaned your throtle body and changed plugs

 

Hello hello! Yup, I have the same issue, same inquiry. Same year, same engine. I cleaned the throttle body, mat sensor, filter, denso plugs. I've been searching forums on cleaning the (IAC-idle control valve) but I'm at a loss with its location. I'm beginning to think the 05's didn't have one. I've done parts searches and it ends at 04'. Were they internal in the throttle body?

 

there is no idle air control valve. Reason being is the throttle body is fly by wire with no direct link to the gas pedal. This means the ecu can control the butterfly to control the idle itself rather than having to use a bypass circuit (idle air control valve) to do so.

 

Thanx for reply. Now I know.

 

With the age of your vehicle, I say to check your vacuum hoses for cracks. Use some Redline Oil S1 Fuel system cleaner, or VP Racing fuel system cleaner, and or change your fuel filter (fuel pump upgrade from URDUSA.)

 

I'm having the same issue with my 06 4.0. Cleaned throttle body, air filter and MAF. I also replaced both my downstream and upstream o2 / AF sensors. Codes I keep getting are P2197- o2 sensor (B2-S1) and P0505- idle air control system. Where do I go from here? Thanks!

 

P0505:


P2197:


I'd check for intake vacuum leaks after the MAF that would affect just bank 2, and also exhaust system leaks before (manifold or gasket) or near (connections/rust/damage to the head pipe) the bank 2 O2 sensor¹.

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¹ - Exhaust gasses flow in pulses with a higher than ambient pressure head, a near ambient pressure body and a less than ambient pressure (partial vacuum) tail. When the pulse's head passes the leak exhaust gasses are forced out of the system, when the body passes the leak nothing happens. Neither of these affects the content of the exhaust gasses.

However when the pulse's lower than ambient pressure tail passes the leak outside air is sucked in making the AFR appear lean, making the O2 sensor appear to be "stuck" lean.

 

Thanks for the reply. I've been sick the past few days so I haven't done anything with my truck yet. I'll look into it and post my results.

 

No vacuum leaks just two bad air fuel ratio sensors. Mystery solved.