I just did the 10k mi oil change (Mobil 1, filter). Very easy identical to servicing our 2002 Toyota Echo. On Friday, 27 May, the "check engine" light came on - no other signs or symptoms. I took our 2005 Prius to Michael Toyota Monday afternoon (2Â mi from our house). The dealer has had the car going on two days. One telephone call said the car would be "ready at 4:30 p.m." The next telephone call said "We don't know what the problem is." I asked if it involved a software upgrade. Response, "We don't know." So our otherwise excellent-performing Prius is in the "hospital" until further notice. Diagnosis unknown. Anyone else experience the "check engine" phenomenon?
Strange... If the computer is throwing a "check engine", the handheld test device should be able to show the code associated with it - shouldn't be any more complicated than that. It wouldn't just be a loose gas cap would it? Dave
The dealer advised today that they have not yet been able to figure out what is going on. Now the vehicle will not start. The dealer is bringing in Toyota Engineers. The dealer is taking a fuel sample. I asked why a fuel sample. The dealer said they did not know. I commented I brought the vehicle in per the owner's manual because the "check engine" light came on. The dealer says that light is now off - and Toyota is still trying to find out what to do.
Dealer called again today. They have not yet figured out what is going on with my Prius - it now will not start. Dealer commented that the vehicle is "running very lean," and again asked what kind of fuel I purchase, where I purchase the fuel, etc. I purchase fuel just up the street from the dealer where many dealer employees also purchase fuel. This is interesting as I keep detailed records and left an Excel spreadsheet of fuel use and distance driven for 10k mi on the front seat. The MFD showed 52.5 mpg when I dropped off the vehicle. I normally obtain 60-62 mpg on my morning 30 mi commute. Fuel economy often drops on the way home with speeds up to 70 mph, hence the 52.5 mpg value. We discussed how there are no modifications to the vehicle. The dealer acknowledged no modifications and said Toyota engineers will be here next Tue-Wed to work with the vehicle. Are people's driving habits so ingrained and poor that deven dealers find it hard to accept a Prius can regularly obtain 50 to 60 mpg?!
Did they pull any DTCs, both when the Check Engine Light (CEL) came on, and now that it is off? Toyota may be working more thorough here to try and see if this is related to the stall scare going around, and if so, what is the cause. If this is related to the stall issue going around, then maybe there is a problem out there not addressed by the TSBs that we haven't heard firsthand yet.
The dealer had the vehicle a full week and tried multiple scenarios. Toyota engineers were brought in. The vehicle was found to be running lean. Pin 33 of E5 connector was found to be pushed out. The Pin was pushed in and the vehicle now starts and runs properly. Even though I had just changed the oil (Mobil 1, 10k mi) and left detailed records indicating I had just changed oil, the dealer again changed the oil "to make sure it was done correctly and on time." Per Priuschat guidance I had a "Mobil 1" sticker in the engine compartment, so the vehicle was refilled with Mobil 1. I picked up the vehicle at 0700. Driving to work I found that everything had been reset. This is a good argument for keeping your own detailed records and not relying just on the MFD. When I dropped the vehicle off at the dealer the MFD showed 52.5 mpg. When I picked the vehicle up it showed 32.5 mpg. My normal 45 km (30 mi) commute got the mpg back up into the 50s. Very happy to have my vehicle back.
I'm impressed about how Toyota handled this. Bright engineers out, take a very close look, find the issue (a pin on a connector... needle in haystack), fix it, and (hopefully) document the issue to improve manufacturing. Another reason why my wife and I are buying Toyotas.
Good analogy: How do you find a needle in a haystack? Either amplify the needle or burn down the haystack. If you amplify the needle it will move. If you burn the haystack, you lose the haystack and the needle. What you want is to amplify and find the needle and keep the haystack. This is multivariate analysis. Realizing there are many onboard chips and subcircuits, I still find it amazing it took a week to find thee connection that was causing the problem.
its great to hear that Toyota was able to solve the problem. lets look at how american manufacturers solve problems granted this was a while back and technology has changed for the better making troubleshooting easier (if you know how the car works i guess) in some circumstances. but i had a co-worker who bought a brand new Dodge Caravan. it died without warning on the Tacoma Narrows Bridge. he took it in, the replaced the onboard computer and gave it back. two weeks later it died again (going in the other direction this time but still on the bridge) eventually he got his money back after more than a year and several more trips to the shop. i dont think they ever did find out what the problem was although at one time or another nearly every part on the car was blamed
