2007 Yaris - Check Engine Light Flashing - Causes?

[white89gt]

Hey guys, I just got to work and had a fun little travel in. The little Yaris was going just fine at 85 mph down I-80, then I went to pass someone. I got to 90, and the CEL started flashing and it made me go back down to 80 mph and quit flashing. A few mile later, I got it to 90 with no issues - but I was able to repeat it 2 more times. I am just trying to figure it out.

I work 40 miles from home, so I am wondering if this is anything any of you have experienced before? My code reader is at home, or I would have done a diagnostic scan already. Because it was flashing and did not stay illuminated, will the code even be stored in the ECU? I am a Ford guy with a Toyota, so I don't know much about how Toyota does things.

Thanks!

[zoidberg444]

Could you feel a misfire when the CEL was flashing? Honestly in that situation the engine being under heavy load i'd suspect an ignition coil was on the way out and was conking out under high load and then working again under lower engine load.

You should read the codes though. Could be all sorts. Should be stored as a history code. Worst case keep your scanner in the car the next few days and recreate the problem if you have to.

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[tmontague]

^that was my first question - did you feel the engine missing and therefore lagging during the flashing CEL?

[white89gt]

Thanks for the replies!

I couldn't feel a misfire. That was my first thought because it acted the same way a misfire does as far as slowing me down, but it didn't shake at all.

A co-worker has a Blue Driver here that he is going to let me borrow. I'll report back what and if it finds anything.

The trans has felt like it has been shifting a bit weird lately... a couple times it has downshifting a bit hard from a neutral condition.

[white89gt]

I went out and started it, and I knew immediately it was what you two said. There is a very slight misfire, so it threw a "Pending" P0302. How does Toyota number their cylinders? I assume number one if at the front of the motor, correct?

It ran smooth throughout the whole drive in to work... I even let it idle for a minute while I poked around under the hood.

So, next question. It has 157,000 or so miles on it. I changed the plugs about 30K ago, and was planning on doing them again before winter. How are the coils on these things? Are they pretty reliable? Is it advised to stick with Denso?

The modular Fords (4.6, 5.4, 6.8's especially) are VERY particular about which coils you use. They only like Motorcraft or Denso coils. So, that is why I am asking.

Thanks!

[TiedBassDrummer]

You are correct, number one is at the front of the engine. It looks like OEM spark plugs can be either Denso or NGK. I don't know how picky these engines are about spark plugs, nor do I know how reliable the coils are.

[white89gt]

Thank you. I put Denso's in it when I changed them, but the original's were NGK's. I think I might switch back to NGK.

[tmontague]

Keep the spark plugs in, they are barely even used at this point since you swapped them.

You have a misfire in cylinder 2, swap that coil with another cylinder's coil and reset the cel. You should have a new code pop up eventually with a P030x where the last digit represents the cylinder you moved the coil to.

That confirms a bad coil

FWIW I have had luck with cheapo coils but I only.put them in a car that I will eventually be scrapping. If I was putting them in a car I planned to keep for a while I would put in OEM sensor's from rockauto

[zoidberg444]

A quick test you should do is to swap the cylinder 2 coil with another 1 and see if the misfire moves. Tells you if the coil is faulty or you have a different problem like a dodgy spark plug or something else.

I'd stick with the Denso coils. They are very good. You might be able to find a decent used one if you don't want to spend the money. The Toyota ones normally nave the part number on them.

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[white89gt]

I pulled cylinder 2 plug, and the electrode was melted. Perplexed, I pulled the other 3 and found them to be the same. I've obviously got a lean condition. On my newer Ford's, I can check fuel pressure with my scan tool - so I attempted to use 2 different scan tools for FP on the Yaris. I do not see it in either list... so I looked all over the place under the hood to find a port to check it. No can find. How do you test fuel pressure on these little things?

These are the DENSO Iridium IK16's that I pulled out of it. About 30K miles on them is all. Car ran fine too (until the misfire).

(EDIT: I put NGK 5464 BKR5EIX-11's back in it)

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