So in the past 600 miles I have seen an E27 - Open Throttle Switch Signal, and E55 - Closed Throttle Angle Out Of Range codes pop up and then go away after a few brief minutes. Each time was while cruising on the freeway at about 2-3k (70-80 mph). Also these occurred separately but I believe they may be related. It should be noted I have been having problems with heat and charging (I believe caused by the heat).

Any ideas what could cause this?

Switch the throttle position sensor off of the other engine. Clear the codes and give ti a good drive to see of it comes back.

quote Originally posted by Dizzixx: So in the past 600 miles I have seen an E27 - Open Throttle Switch Signal, and E55 - Closed Throttle Angle Out Of Range codes pop up and then go away after a few brief minutes. Each time was while cruising on the freeway at about 2-3k (70-80 mph). Also these occurred separately but I believe they may be related. It should be noted I have been having problems with heat and charging (I believe caused by the heat). Any ideas what could cause this?

check continuity of those wires... if all is well there, then swap out your ISC and TPS and recalibrate...

heck, recalibration alone might fix it...

Do you have a scanner or a multimeter?

If so, I would check the sweep of the TPS with either one first BEFORE I replace it (save having to take the time to go through the idle learn). You can also check the throttle switch of the ISC with the multimeter as well. It is easier to test the parts than to replace them (I hate garages that repace parts just because they are too lazy to test them - that or to rack up the bill).

E27 Open throttle switch indicates an issue with either the wiring from or the ISC itself. The throttle switch is located inside there. Basically the PCM is not seeing the circuit closed which should happen any time you release the throttle. It can't tell when you release the throttle so it can't adjust your idle speed properly. Specifically the throttle switch wire is the "pink" wire at the ISC. It connects to "A7" at the PCM. The blue wires are for ISC motor control, blk/wht is the ground.

E55 is a byproduct of the E27. Replace or repair your ISC and/or wiring to and from it. Sounds like its intermittant so its very possible the contacts inside the ISC just need cleaned or you have a loose/broken wire.

Throttle switch and TPS are seperate circuits and systems. I had this problem with my first ISC. It effects idle speed, coast down, ect. When it kicks on the light the PCM may set limp mode and it can effect driveability a little. Depends on the situation. It can also cause a somewhat dangerous "sail on" if it happens and the wrong time. The likelyhood of everything happening just perfectly to cause a danger is very slim. I drove mine around for 2 weeks with these codes and only once did it suprise me. Annoying, but generally not a huge deal. Good luck on the fix Diz.

[This message has been edited by Fieroseverywhere (edited 08-23-2010).]

Actually I have been having sail on problems. Not alot or all the time but they can be annoying/dangerous. I was thinking it was the throttle cable getting too hot and getting sticky in the sheath or something. Sometimes when I take my foot of the gas it lags a second before really idling down all the way and once or twice it has really blipped between shifts, I wasnt sure if it was me, something mechanical, or something electrical, or all three.

So apart from checking the wires and connectors how do I verify the TPS and ISC as being good? I dont want to swap out the ISC especially if I dont have too, as this one idles, granted it idles low but it idles, the last one was kinda a pain. Can someone re post how to correctly perform the IDLE learn I still have yet to ever do this.

quote Originally posted by Dizzixx: Actually I have been having sail on problems. Not alot or all the time but they can be annoying/dangerous. I was thinking it was the throttle cable getting too hot and getting sticky in the sheath or something. Sometimes when I take my foot of the gas it lags a second before really idling down all the way and once or twice it has really blipped between shifts, I wasnt sure if it was me, something mechanical, or something electrical, or all three. So apart from checking the wires and connectors how do I verify the TPS and ISC as being good? I dont want to swap out the ISC especially if I dont have too, as this one idles, granted it idles low but it idles, the last one was kinda a pain. Can someone re post how to correctly perform the IDLE learn I still have yet to ever do this.

You can verify the TPS with your scanner. Check closed voltage and WOT voltage. Then very slowly go through the full range of motion looking for dead spots or spots of varying voltage. About the best it gets. It can also be done with a multimeter. Its a little more involved and a analog meter works a bit better but it can be done.

Once the wiring is checked you can move onto the ISC itself. They are very simple to take apart. I'd open it up and clean the contacts inside. I've seen the inside of 3 now. All 3 showed some form or corrosion that needed to be cleaned off. A very fine file or sand paper works but a couple drops of muratic acid on a q-tip is the best. That stuff is cheap at any hardware store in the paint thinner section. Just make sur to NEVER, EVER put it on aluminum. Trust me, its not pretty.

With your added info I'm certain your issue lies in the ISC motor or wiring. The TPS plays more of a role in fuel delivery then idle speed control. The throttle switch is the exact opposite having almost no bearing on fuel control and everything to do with idle speed. If your having sail on issues its either problems with ISC or VSS or the need for the idle learn procedure. Since its intermittant that cancels out the idle learn.

Think of the throttle switch and the "on" button for idle speed control system. When pressed the PCM can start controlling idle.

[This message has been edited by Fieroseverywhere (edited 08-23-2010).]

Great thanks.