[ggsouber]

My 2001 H6-3.0 at cold start up it will sometimes have an undulating idle with a check engine light. I shut it down, disconnect the battery cable then reconnect it and the problem goes away with no check engine light. It may idle at 1500 RPM and occur when I tap the accelerator. Any of my forum friends have ideas as to whats going on?

 

[plain OM]

Your car is equipped with an on-board-diagnostics (OBD) system. The OBD checks for problems when the engine is running. If it finds one, and depending on the nature of the problem, it will store a code in a memory and it will turn on the Check Engine light. The code that is stored in memory will identify where in the area of the engine the problem is occurring. By reading the code, mechanics will have a better idea of what the fault is and where.

These newer cars are complex, and use a lot of electronics and computer processors to run. Having the OBD is not only helpful, but necessary to enable proper analysis. By disconnecting the battery, you may have turned off the check engine light, but you also eliminated any record of the fault that had been detected. It would be difficult for anyone here, or at a garage, to suggest what's going on to any degree of accuracy, without having the code.

Next time, don't erase the code by removing the battery connection. Take the car to a dealer, or even an auto parts store that has a service department. (Many of the latter will connect a code reader to the car and let you know what the code is without charge.) The code is in the form of a letter, such as "P", followed by four numbers, for example, P0301. Get the code, or codes, and then look it up on the Internet, or report back here.

(Incidentally, you had a thread on this previously: http://www.subaruoutback.org/forums/66-problems-maintenance/44404-2001-outback-h6-idle-surges.html)

 

[boxterfan67]

My 02 H6 LL Bean wagon has an idle surge (if you can call it that) when I go to park it. I'll slow down, still on the brakes, and sometimes the car will surge forward right before I stop completely. It does not do it every time, but I anticipate it nonetheless. However, it is a rude awakening to others who drive my car, i.e. my son, and could potentially be dangerous. Any ideas?

 

[1 Lucky Texan]

I'm wondering if this could be related that recall for the cruise control clip? maybe it fell off and the throttle cables are messed up?

is there a check engine light on?

 

[ggsouber]

I'm only asking if anyone has ever observed and resolved an identical issue like this before, regardless of the code. I will try to find the code out next time it occurs.

 

[boxterfan67]

idlle surge

How many miles do you have on your car? I have an 02 H6 and in the am when I start it it goes straight up to 1500 rpm. I have 167k on mine and just let it run for 20-30 sec then tap the gas. It reluctantly settles to 1000 rpm but isn't terribly smooth. I just chalk it up to a car that requires 6 qts. of oil for a 3 liter displacement, and 9 qts. of transmission fluid. Guess it takes a little time to heat all those fluids up???

 

[cardoc]

I'm only asking if anyone has ever observed and resolved an identical issue like this before, regardless of the code. I will try to find the code out next time it occurs.

The code is the key.

There are a lot of factors that could cause what you describe. When the car is first started the ECM carries out a warm up cycle which includes high idle. As the engine runs, the idle will gradually settle down with increase in engine temperature. It does this for a variety of reasons: Warm up the engine quick, warm up the trans, heat up the CATS and provide quick use of the temperature controls in the passenger compartment.

Once the idle settles down to a regulated 650-750 rpm range, it shouldn't just idle up on its own unless the AC is on and then its only a change of about 50-100 rpm.

So, you need to be more specific. Don't clear the codes, post them. No need in spinning your wheels searching for an answer you want to hear.

Your car is talking. LISTEN to it.

 

[ggsouber]

I have 157k on my 01 H6 Outback and you described exactly what it does upon warm up.
Only sometimes the check engine light comes on right after I tap the accelerator. I'm looking into getting a code reader from Auto Zone or O'Rielly.

Thanks
Rick

 

[ggsouber]

I have 157k on my 01 H6 Outback and you described exactly what it does upon warm up.
Only sometimes the check engine light comes on right after I tap the accelerator. I'm looking into getting a code reader from Auto Zone or O'Rielly.

Thanks
Rick

 

[mhoward]

I would try cleaning your IAC valve (Idle Air Control). I cleaned mine and it idled so much better. It's a simple thing to check at least to see if it's dirty. Then you may as well clean it while its out. Two screws and it's out and visible. Disconnect the battery before cleaning it though. On my truck, whenever someone has an idle problem it's related to the IAC that needs to be replaced or cleaned. Whether that holds true to subarus to is yet to be determined

 

[ggsouber]

With the engine not running and the ignition turned on, I floored the gas pedal 3X. Heard a slight buzz at full throttle each time. I then started the engine and have not had a problem since, no check engine light either. Cold start idle hops right to 1300 RPM until it warms slightly and starts coming down after a couple minutes.

 

[1 Lucky Texan]

there was a clip installed on the CC cable as part of a recall. I THINK to help prevent some tangling or other issue with the throttle cables. Might be a good idea to confirm yours got he clip.

But I don't know if it would create a CEL - maybe a TPS code?

even if my guess is wrong, getting the code next time might help diagnose the car.

 

[eagleeye]

With the engine not running and the ignition turned on, I floored the gas pedal 3X. Heard a slight buzz at full throttle each time. I then started the engine and have not had a problem since, no check engine light either. Cold start idle hops right to 1300 RPM until it warms slightly and starts coming down after a couple minutes.

I don't even think it should take minutes for the idle to drop in a H6. -what is the ambient air temp in your part of the golden state?

I wonder if you are just getting a gummy throttle body just enough to screw up the telemetry intermittently enough to throw a code.

Are you using 93 octane? Have you ever used Seafoam or Techtron? (see threads, put a pint can in on top of a whole tank of 93 octane gas a few times).

You might need to take it to the next level and add it right to the intake, but get the code first. In the old days of tearing into the intakes you could find some brown deposits, seafoam takes it away and makes it passable and burnable.

 

[jogosub]

Try cleaning or replacing Subaru Idle Air Control Valve (IACV) OEM P/N A33-661-R02 - as mhoward mentioned earlier.
You can get them on eBay for about $ 50.00
It's located at throttle body, held in just by 2 screws, with blue label showing the above P/N....make sure to disconnect the battery, when you are changing or cleaning it!