Yaris Idle Problem

[mark1962]

hi I have a 2002 yaris 1.0 and when you take your foot off the throttle the revs go down but at the last second it seems to rev back up only very slightly and the throttle does seem very lively , I can drive round this but my daughter is learning and finds it difficult ...any ideas ?

[Cyker]

What's it idling at? Should be something around 800rpm...

It sounds a bit like the clogged EGR issues the diesel ones get but I don't think the petrol Yarisususes have EGR's...

Might be a sticky idle control valve...?

Worth checking the air filter too.

Did you mention it last time the car was serviced or did it only start doing this recently?

[mark1962]

1. HI THANKS FOR REPLY IT DOES IDLE AT 800 RPM BUT AS IT GETS THERE IT HAS A LITTLE REV UP TO 1100 RPM I'VE TOOK AIR BOX OFF TO SEE IF IT MAKES A DIFF BUT STILL THE SAME AND YOU CAN HEAR IT SUCKING AIR AS IT REVS ITSELF . IS THE IDLE CONTROL VALVE ON THE OPOSITE SIDE TO THE THROTTLE CABLE ? THESE VVTI ENGINES ARE NEW TO ME , ONLY JUST BROUGHT CAR FOR MY DAUGHTER TO LEARN IN SO NOT BEEN IN GARAGE AS I CAN DO MOST THINGS MYSELF BUT NOT THIS, I'M A BIT STUMPED.

CHEERS MARK

[Cyker]

TBH I couldn't tell you. IIRC it's attached to the throttle body??

Might be worth doing a search on here and google for more useful info.

From what I've read, some people also say it's the idle control valve or sensor, others say it's a problem with the throttle body, and others say it's normal!

At this point we'd need to wait for one of the Yaris owners who actually knows what they're talking about to chip in

[Madasafish]

My first port of call is a gummed /carbonned up throttle body which restricts the closure of the throttle valve. A good dose of carb cleaner - used according to the instructions - should clean it.

(That's the simple and and cheap solution.).

You should also check ALL vacuum hoses connected to the engine - and the crankcase breather PCV valve . The hoses may have leaks and the breather may be blocked Also check the valve where the breather tube is attached to the cam cover- to the right of the oil filler cap. This may be blocked. The valve should operate freely. See pictures http://tinyurl.com/o3c3vwf

see also http://tinyurl.com/pf8q9lg

[Geoff Peace]

TBH I couldn't tell you. IIRC it's attached to the throttle body??

Might be worth doing a search on here and google for more useful info.

From what I've read, some people also say it's the idle control valve or sensor, others say it's a problem with the throttle body, and others say it's normal!

At this point we'd need to wait for one of the Yaris owners who actually knows what they're talking about to chip in

I agree with cleaning the throttle body, checking hoses etc. Another thing which can cause this problem is, if you look at the back of the engine, near the bulkhead you will see the ide speed control valve. This is fed by two very small bore hoses from the cooling system. If one or both these hoses become blocked/restricted, (not unknown!) the engine will not idle correctly because coolant is not circulating freely through the ISCV . I would remove and clean both hoses and the valve where the water circulates. Refill the cooling system slowly, warm the engine slowly to disperse and air locks which will, if present, have the same effect as blocked ISCV hoses.

Regards Geoff Peace.

[Stig.00R]

Where is the throttle body, I have 2003 Yaris and can’t seem to locate 

[paul9]

Follow the pipework from the air filter box which should feed into it.