Need advice on enginge light, keeps coming back on

heavymetalrock

Hi, would love some advice about Toyota yaris, for the past 3 months i have been having problems with the engine light coming on, it has been down to the garage lots of times and i dont know what to do.
Heres how it started, first time it came on , brought it down to my garage and it was failing on some of the mission test, so he use some engine cleaner in it,
that work for a week, then it came back on after that so he replace the oxgen senor, and check the mission again and it passed on everything, little over a week it came back on again, and he s think the catalytic converter might need to be replace, the car is driving fine apart from the light being on.
i told him now if he needs to replace the catalytic converter , do so,
i know they are dear, but i just want that light off, but he is says now, that if the car is driving fine and it has passed the mission test, then dont replace the
catalytic converter .
please help:(:(

Pov06

It's a common issue on the Yaris.

Most of them have this problem even though they pass emissions without problems and don't use more fuel.

Just ignore the light and drive on!

Mine was exactly the same expect I didn't change anything What's happening is you're getting the P0420 DTC. The ECU seems to be too picky on this car.

heavymetalrock

will it still pass a nct, and ok to drive?

Pov06

heavymetalrock wrote: »

will it still pass a nct, and ok to drive?

Yes, the check engine light being on in a petrol engined car will pass without problems. You can drive it without worry.

Bicycle

I've an Avensis with a similar problem. Last year after I passed the NCT, the emissions light came on as I was leaving the NCT centre.

I brought it to my local mechanic who fiddled with it and said it may or may not go off after some driving.

Got it checked again this year before my NCT - light wouldn't go off despite them checking and changing some of the sensors.

So I brought it to the NCT Centre to see what would happen. And yes it failed the NCT on emissions but not by much - but the guy doing the test tested my car for FAR longer than anyone elses car. And it was only one of the emissions test.

I brought it to a main dealer before the re-test and they ran it through their NCT test - no problems. But said 2 of my sensors were gone. I could spend €500 replacing them.

So I took it to the NCT retest and it flew through it - despite no remedial work having been done.

At the moment, I don't have €500 to spend on something that isn't keeping my car off the road so I'm leaving it. My NCT is valid until next summer. I'll have a rethink then.

biko

Cars with engine light on - will they pass NCT?

If petrol - yes
If diesel - no

Note, the car may still fail on the cause of the light. If the light is on because the emissions are screwed up and a sensor needs changing then you will fail the test. But if light is on and everything else is ok you should pass*

*no promises

Toyotafanboi

Our yaris had the check engine light on for maybe 3 or 4 years with the oxygen sensor fault code. Always drove fine and always passed NCT emissions too.

Finally the cat gave up this year (presemably from dealing with the faulty oxygen sensor for o long) and failed the NCT.

New oxygen sensor and new cat and we had change from €500 iirc.

biko

heavymetalrock wrote: »

ok to drive?

Maybe, we don't make that judgement for you.
It's entirely up to you and your mechanic.

heavymetalrock

i understand what your saying, i just never had this problem before with any car i had, thats why i m asking for advice

Pov06

heavymetalrock wrote: »

i understand what your saying, i just never had this problem before with any car i had, thats why i m asking for advice

With the Yaris, it's absolutely fine. Most Yarii that age suffer from this problem yet they pass NCT.

Drive her on! Mine was like this for 2 years

ironclaw

You can remove the O2 sensor very handy in either version of the Yaris. Online you can find a video or instruction set. All you need is a screwdriver and about 15 mins. Carefully & gently clean the unit with some mild solvent and a q-tip. Will probably solve the problem as it happened at least 3 I know, including my own, and this cured it.

heavymetalrock

got the car back again from the garage, and this time it failed on the missions so i have to get the catalytic converter now and he price one with a Toyota , and its 600 plus fax, that's very dear so he looking around some where else, does anyone know what price i would be looking at?

ironclaw

heavymetalrock wrote: »

got the car back again from the garage, and this time it failed on the missions so i have to get the catalytic converter now and he price one with a Toyota , and its 600 plus fax, that's very dear so he looking around some where else, does anyone know what price i would be looking at?

What year is the car? I'd be shocked if it needed one to be honest.

heavymetalrock

06

Pov06

heavymetalrock wrote: »

06

Mk1 (the old shape) or Mk2 (the new-er shape)?

Which engine? (1.0/1.3/1.5)

If it's the Mk2 with 1.0 engine then I would suggest you ask your mechanic to check the spark plugs. It's a known problem with them that the spark plugs get covered with carbon deposits and create a bad spark due to failed oxygen sensor or catalytic converter.

I would try the spark plugs before doing the catalytic converter because the spark plugs only cost about €1.50 each and you need 4.

heavymetalrock

1.0 engine,
MK2 ( The new -er shape)

Pov06

heavymetalrock wrote: »

1.0 engine,
MK2 ( The new -er shape)

Pov06 wrote: »

If it's the Mk2 with 1.0 engine then I would suggest you ask your mechanic to check the spark plugs. It's a known problem with them that the spark plugs get covered with carbon deposits and create a bad spark due to failed oxygen sensor or catalytic converter.

I would try the spark plugs before doing the catalytic converter because the spark plugs only cost about €1.50 each and you need 4.

^

ofcork

I had that light on in my last avensis over 4 years and passed all nct no probs with no sensors or cat replaced.

heavymetalrock

thanks will get him to try that first.

Cerco

One problem with ignoring alarms is that a more serious problem may occur and you may not be aware of it. It could end up costing a lot more.:eek: