I have a 2002 VW Cabrio. Unfortunately, I live in the middle of nowhere, two hours from the nearest VW dealer, and I haven’t found a mechanic around here that doesn’t look at every European car like it’s a Martian spaceship.
My “check engine” light came on a couple of days ago, and since I was due for an oil change, I took it to the shop. The only trouble I’ve seen from it is that it will occasionally die when I first step on the gas in the morning, but once I’m on the road I don’t have any problems at all.
He hooked it up to his computer, and it told him that my idle strategy had reached its limit. He briefly explained to me what an idle strategy is (though I’m not sure I totally get it) and said that he’d never seen that problem before, and didn’t know what to do about it. (They’re not the sort of folks to, you know, look stuff up or anything.)
So how big a problem is this? What do I do about it? Should I still be driving the car?
Some condition, as yet unknown, has a negative effect on idle speed. The computer can adust for such things to a degree. In your situation, it has gone as far as it can in said adjustment. This indicates that the problem is big enough to need fixing (in the computer’s eyes - a line has to be drawn somewhere between normal variation and something broken - you’ve crossed it).
I would expect the condition to deteriorate, likely to the point where there’s severe hesitation and/or poor idle quality, perhaps even dying at stops. It’s not a huge problem in terms of the mechanical health of the vehicle, but it could develop into a significant annoyance or even safety concern for the driver.
First, one should look for the obvious, such as a rotted or disconnected vacuum hose or wire. Next, I’d check the throttle body for carbon build-up, which is a common cause of this sort of symptom in many different cars, and clean it if there’s any noticeable deposit. It’s even possible that a bottle of Techron fuel additive could resolve the issue. If the symptom persists, the next steps require someone who knows how to work on these systems.
In reverse order. Should you be driving the car? No, if fact this problem is so serious you should stop driving it right now, go get the tittle and sign it over to me. I will come by and dispose of the car as I am a trained professional.
Seriously, it is a problem, but not a huge one. here is the deal. you car has a throttle plate that at idle allows a little air to flow past it (if no air got into the engine it would die). Back in the old days, there was just a throttle plate, and no other way for air to get into the engine. This presented two problems. First off the load on an engine varies at idle (In gear, out of gear A/C on or off, engine cold, electrical load etc) this meant that the idle had to be high enough to accommodate all of these conditions. A high idle speed wastes gas, and is uncomfortable for the driver. The second problem is the throttle plate gets dirty, and passes less air causing a problem with the idle speed.
to combat these issues, the engineers developed idle speed control systems. These systems either use an Idle Air Control Valve called a IACV for short, or on newer cars the throttle plate itself is electrically operated, (fly by wire, no throttle cable) and it can open/close itself a bit to make these compensation.
In both of these systems, the goal is to allow just enough air into the engine to maintain a the set idle speed. Now as the throttle plate will get dirty over time, the system adapts its set point for starting its adjustments. Let’s say that the system has a adjustment range of 25 steps plus or minus. The engineer designed the system to run a a zero position on the perfect engine. Your engine is not perfect, so it runs at +5. as the throttle plate gets dirty that +5 will turn into +6, +7… until it hits +25. At this point the idle system as adjusted all it can adjust. It needs to go to +26, but there is only 25 steps. :smack: This is in the position your engine is in right now. It needs to adjust, more, but it has run out of adjustments.
Possible causes include:
Dirty throttle plate
Air leaks in the intake system
Vacuum leaks in the intake system
Dirty fuel injectors
Thanks to all. I contacted my nearest VW dealer (in Lexington) who said pretty much the same thing you guys did. (He said this code was a real pain in the ass for them, because it’s pretty common and there are about 500 things that could cause it.)
