# 00533 - Idle Speed Regulation



## frickingphil (Feb 24, 2009)

00533 - Idle Speed Regulation
09-10 - Adaptation Limit Surpassed - Intermittent
---
Sound like the IAC / ISV to you? 
I tried cleaning it, and it idled a bit better, but still died a couple times. 
Cleaned the MAF as well, haven't driven the car since the stuttering though.
*Symptoms: *
-Car sometimes dies immediately after starting / any time during idle, like in between shifts, or when clutching in coming to a stop
-Car also misfires / loses power randomly, usually between 1-2k rpm's, but sometimes above it. (i think this may be the fuel filter or other tune-up related items)
It's a '95 Golf Sport.



_Modified by frickingphil at 10:13 AM 7-14-2009_


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## 97VWJett (May 17, 2003)

*Re: 00533 - Idle Speed Regulation (frickingphil)*

Clean the throttle body and you will be set.


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## frickingphil (Feb 24, 2009)

*Re: 00533 - Idle Speed Regulation (97VWJett)*

You sure? Throttle body on OBD1 cars doesn't affect idle, afaik...but I'll go ahead and do that anyway. Couldn't hurt to be thorough.


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## frickingphil (Feb 24, 2009)

*Re: 00533 - Idle Speed Regulation (frickingphil)*

bump


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## ognjen28 (Jul 8, 2009)

*Re: 00533 - Idle Speed Regulation (frickingphil)*

coil maybe? Vacuum leak? Tune up?


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## Quintman (Oct 2, 2004)

*Re: 00533 - Idle Speed Regulation (ognjen28)*

i had a similar issue, same code. What i ended up doing is adjusting the throttle body angle with that screw on the backside of it. if you use vag com, i adjusted it to 15 degrees at idle, and then let the idle settle down and it went away. I think there is an underlying issue but i swapped out several things and nothing fixed it (coil, wires, plugs, cap rotor, isv, tb, maf).... on mine you could rev the car and it would start stuttering right at 1400rpm. if i held it there and cleared the code it would instantly run smoothly, and if you hold the rev up the code doesnt come back. its something to do with airflow at idle but i dont know what...


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## frickingphil (Feb 24, 2009)

*Re: 00533 - Idle Speed Regulation (Quintman)*

Unplugging the ISV produced all the symptoms, 100% of the time. Stuttering, rough/hunting idle, etc.
In addition (after re-plugging the ISV) it's now pulling a different code:
01257 - Idling Speed Stabilization Valve (N71)
31-00 - Open or Short to Ground
I should replace the ISV first, huh? All the signs seem to be pointing to it.
I'm worried that it might be the wiring though...


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## Quintman (Oct 2, 2004)

*Re: 00533 - Idle Speed Regulation (frickingphil)*

you can try, but mine did the same thing and isv didnt fix it. i dont think its wiring because you can clear the code and it goes away for a bit... its really weird.


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## frickingphil (Feb 24, 2009)

*Re: 00533 - Idle Speed Regulation (Quintman)*


_Quote, originally posted by *Quintman* »_you can try, but mine did the same thing and isv didnt fix it. i dont think its wiring because you can clear the code and it goes away for a bit... its really weird.

Maybe it's an ECU problem?


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## Quintman (Oct 2, 2004)

*Re: 00533 - Idle Speed Regulation (frickingphil)*

i dont think its ecu.. i was wondering about the egr but im not sure how that works and if it could cause it. my only explanation is that, the isv allows extra air into the intake to adjust idle, if there is not enough air it allows more in, it only can until a certain point, then its open all the way, and throws the code, the reason it make its run bad is because as soon as you open the throttle just a tiny bit its lets too much air in and therfore runs poorly, by opening the throttle a little, it allows the isv to back way off and smooths things out. this is only my theory, i have no idea if this is even close to right, or what would cause it.


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## frickingphil (Feb 24, 2009)

*Re: 00533 - Idle Speed Regulation (Quintman)*

Replacing the ISV fixed all my problems.
Good luck on your end.


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