Yellow Check Engine Light

Good morning:

Today I had the yellow check engine light appear on my dash. Concurrent with that light coming on I noticed the car appeared to be running rough. At this time I also noticed that the state of my hybrid battery indicator light on the screen was completely white. No blue bars; No green bars. Just pure white.

I believe it is relevant to mention that this occurred immediately after I had performed the manual forced reset procedure to reset my malfunctioning combination meter. That procedure is: push power button without placing foot on brake; press and hold the info button on the steering wheel while simultaneously flashing the headlights 3 times; finally, place foot on brake and press the power button again. I have had to rely on this reset procedure dozens of times over the last year with no problems arising.

Side note: my 2008 prius has 210,000 miles on it and has been impeccably maintained, EXCEPT for the combination meter which I cannot justify spending $800 to fix because of the year and mileage also have a 2015 Toyota Tacoma with very low miles. I use the Prius as my daily driver to avoid putting miles on my Tacoma.

Anyway, I pulled over; shut off the car and did a visual inspection under the hood and noticed nothing unusual. At this time I also looked up the significance of the yellow check engine light in the owner’s manual. It said it could be one of three things: The electronic hybrid system control system; the electronic throttle control system, or the transmission control system.

When I attempted to restart the car it started right up with no issues and I noticed the yellow check engine light was no longer on; the hybrid battery indicator showed blue bars which soon turned to green bars, and the car ran normally. I then proceeded to drive the car 70 miles home without the yellow check engine light coming back on. The car appeared and appears to run fine now.

With the car running fine I stopped at my local auto parts store and requested that they run a systems scan. The scan revealed that cylinders 1 and 2 had experienced a misfire (Hence the car running rough).

If you have ever experienced this before I would appreciate you sharing your experience and what the outcome and/or fix was.

 

My Prius has had a complete tune up and I replaced the air filter both within the last four months.

 

JC91006, I have been using this combination bypass procedure for nearly a year. I tried to find the link where I learned how to do it, but I am unable to locate it.the misfire occurred on the highway about a mile after I performed the combination meter bypass procedure. Is it even possible to drive the car (especially at highway speed) if it has not entered "Ready mode"? pardon my naive question. I am unfamiliar with the technology.

 

Thank you for such a thoughtful and thorough reply. I sincerely appreciate it.

 

Ugh. The yellow check engine light came on again today. This time it was not flashing, but was solid. I had a different auto parts store run a diagnostic test and it revealed that cylinder 1 was misfiring. In my opening post I mentioned that the yellow check engine light was flashing at that time cylinders 1 and 2 were misfiring. I have an appointment with my dealer tomorrow. I'm told they want to start with a tune up and coil change. But the engine is not making a clattering sound as mentioned above. So now I am hesitant to proceed with that course of action. Without guessing (and spending my money needlessly), is there no way for a dealer or service shop to accurately diagnose the cause of the misfires?

 

I have the oil changed every 5,000 by a local toyota dealership. The car does burn oil so I am very careful to check the oil frequently; 2-3 times each week. I use Mobil 1 synthetic "high mileage" oil.
If 2-3 times a week seems like overkill it's because I drive between 35,000-40,000 miles a year.

 

HI all,

Here's an update. According to my dealer the yellow check engine light was on because of a misfire in cylinders 1 and 2. This is also what a local auto parts store diagnostic scan had revealed a few days before I got it into the dealer. The dealer said they scoped the cylinders and that scoring is evident in all cylinders and that all four of my plugs were fouled. They attribute the oil loss to the scoring (there is no evidence of leaking) and they attribute the plug fouling to the engine burning oil at an unacceptable rate. They said my engine was at or near the end of it's life.

I changed my plugs 24,000 miles ago, but it should be noted that I also let my car idle quite frequently for up to an hour at a time during the winter when my dog is with me and I'm having breakfast in town or running into a store.

The car consistently burns about 1 quart of oil every 1,000 miles or so and has for roughly the last 40,000. The odometer presently reads 204,000 miles.

The dealer said that a band aide fix would be for me to change the spark plugs at more frequent intervals which I can do myself. I had the dealer put in a set of plugs while it was there. I have put over 600 miles on it in the last four days and the engine light has not yet reappeared and the car seems to run as it always has prior to the check engine light coming on for the first time ever last week.

Here's the deal guys. I presently put 500-700 miles per week on this car. In recent years past I was putting nearly 40,000 miles per year on it. I own a cabin on a river in remote northern Michigan where I intend to retire within the next 14 months. I presently make the 450 mile round trip drive EVERY weekend to spend 3 day weekends there each week remodeling my place.

I have a 2015 4WD Access Cab Tacoma in my garage at the cabin. It has low miles (26,000) on it and I hope to keep it that way by putting all the miles on my Prius.

I'd REALLY like to keep this Prius running so that I can use it as my back and forth vehicle until I retire. What does everyone think? Can I keep this car going and reliable for another 30,000 miles? Are there any inexpensive oil additives that I can add to facilitate this goal? Edthefox5 mentioned that I should switch from 5w-30 oil to 10w-30 oil.

Your thoughts, shared experiences and suggestions would be- and have been- tremendously appreciated.

Edit: Was discussing my Prius' issue with a friend who is a decent "backyard" mechanic. His thoughts were that the plugs probably did not become spontaneously fouled out the day the check engine light went on. Instead he suggested that after 24,000 miles and plenty of engine idling on the last set of plugs, that the plugs finally became fouled enough to cause the misfires.
Your thoughts?

 

Thank you for sharing your experience and for the words of hope.