Throttle switch test

[Sgt_Lemon]

Car started having really high idle a few days ago and have found that there is no change to idle when the throttle switch is unplugged. I tried a live tester to check the switch but got no live. Is there more tests I should do and where does the other end go so I can check there?

[oakgreener]

They go to the ECU

[Mr Blue]

Common for the wires to break near the throttle switch.

Plugged in, engine running.

rev the engine just past idle, press the throttle switch - the revs should drop.

The other switch is for wide open throttle if I remember correctly.

No diagram but just beep test the wire to the ecu or Pin 11 according to this

http://www.a2resource.com/electrical/management/digifant2.html

[Sgt_Lemon]

Thanks, at the moment I don't have a multimeter so I can't run a circuit test on the wires. However I do have a live tester. At what points should these wires receive a live signal? I found an inline splice further down the connection earlier that looks ok but I want to check the live on ecu side.

[oakgreener]

You'd be looking at very small voltages and you won't be able to determine very much without a circuit diagram and an amount of electronics know-how. All you can do is check the continuity of the wires and that the switches are working properly. You can do this with a multimeter set on the ohms scale.

[Sgt_Lemon]

Got the Haynes manual out to find the wire locations. Have checked the switch wires back to ecu and there is no break in the circuit. Checked the voltage across the switch and it reads 5v as the manual states. I wanted to remove the throttle body from the inlet to have a look at the switch mounted underneath however the Allen key near bent it half before the first bolt came loose so I would rather not risk trying to get it off. Is there something else which could be the cause of this problem? The car still holds the symptom of high idle and there is zero difference when the throttle switch is unplugged. When the full open throttle switch is pressed by hand the idle drops back down to the recommended range.

[weazgti]

Now go pull blue temp sensor plug off. If there's no difference then you want to be looking there

[Sgt_Lemon]

Coming back to this again, I dug out my Haynes manual for the wiring diagrams and was able to do a circuit test on all the wires the the throttle switch, they were all good. That suggest to me that its past that switch and must be one of the two mounted on the throttle body. Is there a way to test both the top and bottom one (potentially replace) with the throttle body still on the car. The Allen key bolts look perfectly rounded and I don't want to mess with trying to remove it.

[gazareth]

both switches do exactly the same thing. which is why if the idle switch isn't doing its job and you press the wide open throttle switch your car will idle right. with the throttle fully closed you should have continuity at the 2 terminals on plug. and continuity with throttle fully open. with the throttle anywhere between the 2 it should be open circuit. so it defo looks like you have a fault in the switch under the t/b.

[Sgt_Lemon]

I thought as much, if I push in the open throttle switch on top the idle calms down, Atm I have the idle screw out to compensate. Can the switch under the t/b be taken out while leaving the t/b on the car?