High Idle Issue Mechanic Can't Figure out issue

That makes sense. But we're running out of things it could be. How many places did they unplug in order to test for vacuum leaks?

 

That I do not know. That was mechanic #2. But I wonder about them anyway.

 

This may sound silly but did you make sure there's nothing blocking the accelerator pedal from coming up all the way. We had a customer come into the shop for a high idle complaint one time and the floor mat was just catching the edge of the pedal enough to elevate the idle.

 

I was thinking this too. The engine thinking it's still cold.

 

All of the above.

Since you have a obd scanner, try using the erase codes function. Even if there are none, I've had luck chasing away the odd gremlins doing that.

Just for kicks, check for good ground continuity between the ground terminal and engine block with the battery disconnected. Google "testing coolant for electrolysis" and check it.

 

Without pictures, and even some videos. This is going to be very challenging.

 

So we have a new throttle body, reflashed computer no change.


I guess they check the Power Steering Pressure Switch yesterday, disconnecting it and the RPM's went down to normal. Replaced the switch and plugged in and it went back to high idle. They are thinking possible an issue in the wiring or circuit?

 

I don't feel like going back through the prior posts. Do you have an after market wired in radio, or anything else aftermarket wired in?

 

Yes

 

Sometimes that wiring can lead to strange problems. It might be worthy to check over any add-ons you guys have done.

 

Of course when we brought it to the 3rd mechanic, we took the stereo completely out. They also looked at the schematics in detail twice and have said that the wiring from the radio is not in any way connected in such a way that this would cause this issue. My husband also looked at that wiring schematic for the radio and also doesn't see anywhere how it could be related.

 

I think I'd want to look at the power steering pressure switch PID in scan data, if it's on all the time with the switch plugged in and the switch is new I'd put a gauge on the power steering and see if it's building up too much pressure for some reason and keeping the switch turned on which in turn would increase idle speed.

 

I beleive that is what they are looking at now, or the next step. I beleive my husband said that they said basically the same thing you just did.

 

So I guess they just disconnected the switch. Idles where it should. We are out of ideas and no more money to throw at this especially since we still owe money on it. Just stuck. I asked about the building pressure to my husband and he said that the mechanic stated that there isn't a way to test it that there are no specs on what that pressure should be. So it's a wire-maybe? Pump? Fluid is not low or leaking either.

 

It sounds like this is almost root-caused now. Can you disconnect that switch and drive like that for a while? If it doesn't cause you any issues, perhaps you can delay doing any more diagnostic work on it until you're ready. I'd think the worst thing that can happen is you'll have the engine idle speed drop more than desirable if you're asking the power steering to do a lot of work when your foot is off the accelerator. You'll figure out if that's an issue for you soon enough, and be able to see if the high idle ever occurs in operation. Just a thought.

 

I've asked the question of my husband, I guess the ball is in court now. I did talk to a couple mechanics that said they've seen these broken off and I can drive without it. But my husband is concerned about hauling our boat and some of the tigh curves we have when doing that. Why this just started out of the blue boggles my mind. $1500 into it now. ugh.

 

Based upon what @Dm93 said, I think that switch only matters when you're idling. The power steering puts a load on the engine and the already pretty low idle speed could drop more than desired which is why Toyota put it in there. If you're moving a boat around, you won't be idling that often. And like I said, you'll figure out if it's an issue soon enough, in which case you can just plug it back in yourself.

 

Correct it is there to raise idle speed to compensate for the extra load of steering at slow speeds, not a huge deal if it doesn't work you just may notice slightly increased steering effort is required when trying to steer while idling.

 

Switch should be open for normal operation and closed to create a high idle. If you've unplugged switch and idle returns to normal, it is likely that switch has went bad.

In addition to the power steering, some other things to check for high idle is that there is also an idle up circuit if you have the 120VAC voltage inverter, driven by the input "ELS2" into the ECM, an idle up driven by "ELS" signal via the tail light circuit ECM, and an idle up for AC controls via the "AC1" circuit in the ECM.