legacycentral bbs

Hmm...

The idle switch code is a weird one.

The idle switch is an on-off switch built into the throttle position sensor that tells the ECU when the throttle plate is closed. It has to be fairly precisely calibrated.

But, the code also seems to come up sometimes even when the idle switch isn't malfunctioning. The times I've seen it, it seemed to be a result of excessive current draw from the TPS power supply pin of the ECU. This could be a result of a bad TPS or of a wiring problem.

Well, As you seemed to have noticed in my other post, I am considering replacing the TPS (although I have done nothing yet to test it)... but now I guess i'm considering replacing the whole throttle body.
I'd rather only have to replace the TPS seeing as it is only 2 screws and a clip, but it seems that is not necessarily easier than doing the whole TB due to the need to re-calibrate the Idle switch, supposing I am understanding you correctly.
Is it pretty much a sure thing that the Idle switch will be mis-calibrated if I just try the TPS swap?


Sorry if I'm being a pest... I just wanna enjoy driving again...

I recently had a guy (service and parts manager) that works at a Subaru dealership tell me that most dealership techs are great for routine maintanance but weren't very good at diagnostics.

I had a local Scuby dealer tell me it would cost an hours labor ($54) just to scan my ecu!!! Now everyone here nows that's a 10 minute job, tops. They're thieves, that's what made me start doing my own work.

Bosco wrote:Is it pretty much a sure thing that the Idle switch will be mis-calibrated if I just try the TPS swap?

Well... your question is a lot like asking "if I draw two lines on a piece of paper, will they be exactly 35 degrees apart?" They will, if you use a protractor and straight edge.

The TPS has a little bit of rotational play in its mounting hardware, and you have to set the position such that it's calibrated, using some feeler gauges and a continuity tester:

http://www.main.experiencetherave.com:8 ... sting2.jpg

Matt's right... most automotive techs in general aren't great at diagnostics. The follow the troubleshooting guides and eventually find the problem by swapping components and stuff. It ends up taking a lot of time (which they usually charge you for) and can cost a lot in parts if they choose to charge you for those too.

That goes double for engine management problems in particular. It seems like very few automotive technicians actually understand how engine management works, especially when it comes to things that are specific to a particular car. As an example, I had a guy who'd worked for a long time on Subarus offer to "adjust my idle." He was gonna adjust the throttle stop screw. When I told him about the IAC valve, he said it was "just a sensor."

This is basically all you need to know in adjusting the tps.....or at least testing it

http://www.main.experiencetherave.com:8 ... sting3.jpg

Thanks Again

OH BOY OH BOY OH BOY!!!! It's rolling again!

I Changed out the Throttle Body, and have so far driven it 50 or so miles today with no problems whatsoever! NO CEL codes...No jumpy spiking RPMs...No Power light flashing.... Nuttin!
I'm Overjoyed!

I was just trying to calculate how much I'd have spent if I'd let the dealership take care of this.... about $1100 for the Guage cluster with installation, then more $$ for More diagnosis, because that would have done me NO good... Then However much $$$ the TPS and associated Idle switch calibration would have been.... OMFG!
I had what I needed in my parents' barn on my spare engine... cost me $0.

I am forever indebted to you fine folks for helping me through this!

Thankyouthankyouthankyou!