"engine" light, code P0505

P0505 indicates some problem with the electric idle system. I would check to make sure that the air cleaner is in place, check the hose(s) going to the PCV system and look for any other hoses that may be cracked or have come loose. If you can't find anything wrong, you may need to take it in for service.

 

There's some discussion of PCV in my 100k maint pages.
I still haven't ever changed mine out, despite having a new
one in stock.
.
If you get the engine running and then flip to Neutral, what
happens? How does it run? Does it hunt around, does it idle at
what sounds too high or too low, etc? Does it change if you
remove the air box cover?
.
It's worth making sure the MAF is clean and the throttle plate
moves relatively freely when it's not powered up, as initial
checks, and of course eyeball as many hoses as possible. It's
fairly easy to pull the air box off and check around underneath.
And a look at what's *in* the air box, e.g. condition of the
filter and intake snorkel, can't hurt -- you might have had
critters build a big ol' nest in there and block airflow.
.
_H*

 

I personally wouldn't mention it in the context of an inspection, since a check engine light is typically prima facie evidence of emissions system failure. do not know if you need an emissions test.. depends on where you are in PA.

I have my own issues with the ridiculous inspection system in PA, but that's for another thread.

 

In that case, you'll need to drive the car around 100 miles or so, after cancelling the DTC. The engine ECU keeps track of how many miles have been driven since DTC were cancelled, and will not allow emissions testing before the threshold is reached. This is to discourage owners who have a DTC from cancelling it just before taking the car for a test.

Although you didn't find any problems, you should not assume that all is well. It would really be better if you had your car serviced at the dealer to determine where the problem is, prior to embarking on your road trip. Perhaps the throttle control motor is beginning to bind.

Of course you would first have to drive the car sufficiently so that the warning light and DTC reappears. The Toyota tech probably would not appreciate your indicating that you had cancelled the DTC before bringing the car in. Other DTC besides P0505 may have been logged that your Scan Gauge did not pick up.

 

Well, if you plan to take your car in for service I still think that you should drive the 100 miles today. Stop a couple of times during the trip and turn off the car. Include both city and highway driving during the trip.

Then, if no warning lights appear, go to your emissions test tomorrow as scheduled. If the CEL comes on, cancel the emissions test appt and instead take your car to the Toyota dealer to see if they can fix the problem before your road trip starts.

 

Assuming you are using some sort of code reader, it may show monitor status. If it does, in the state of NC all but one monitor have to be complete for an inspection to pass (2001-2010). Your long trip has caused it to no doubt run all the monitors, but good info for future referance.

 

Is this a common issue on the 2004 Prius? I have close to 130k and the same P0505 code. And I have to pass inspection, but after resetting the light the code comes back within couple of days. The code started popping about two years ago, rarely at first and inspection passable. Now is almost ON all the time. Car runs fine, mpg the same, but at stops idles rough, then code pops (unless is there already). What's interesting is that if I reset the code right when it's running rough, everything become normal, the gas engine will shut right away. Also the code seems to like humidity (most likely to pop when air is humid and rainy weather). Luckily I just fished off a throttle body assembly from a 2009 off eBay and I hope it will solve the issue. Dealer price for throttle valve body: $932, ebay price $140. I am curious what was the solution for the PA Prius.

 

Hi PA Prius,
What exactly did you do when you mentioned throttle body cleaning?
Thanks

 

Thanks.

 

My 20006 Prius check engine light also went on for the first time yesterday after 123K miles. Could this also be caused by the cabin filter? I started to change that filter a long time ago and couldn't find it and never did it. Is that filter necessary? Is it behind the glove compartment somewhere? thanks.