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2003 Lancer ES, need advise

I have a 2003 Lancer ES, it has 86k miles on it all driven by me.

Last week I noticed a buzzing sound coming from the engine area when shifting from P to R or from N to D or R. It’s like a buzzing, it only lasts a few seconds and happens even when car is off (engine off and key in on position) sound goes away after a few seconds without me doing anything. Here is me doing it twice back to back from P to R -

I also noticed that when after driving when I put it in park the engine will rev to about 2 to 2.5k rpm and go back down immediately (and doesn’t do it again). From my research it seems to be a transmission solenoid? There is no check engine light and when I took it to AAMCO they tried to read stuff with a computer but it was clear. They recommended I drive on it until CEL comes on, is this good advise? What about revving when parked is that the behavior of sticking solenoid? I took it to another AAMCO and they recommended I change it. Both places quoted me $360 for labor plus the part.

My questions are, should I change it? If so should I do all of the solenoids or just the failing one? Should I drive till CEL? Do symptoms sound like solenoid? It does it from P to R and from N to D are those the same solenoid?

When I’m driving normally the car feels fine shifts seem good and every gear works.

I did the following at 65k miles:

  • Changed Power Steering fluid
  • Transmission Flush
  • Spark plugs
  • Ingition wires
  • Cam positioning sensor (both of them)
  • Alternator belt
  • Power steering belt
  • Timing Belt
  • Ignition wires
  • Spark coils


This is not normal and I suspect that it’s being caused by your IAC circuit.
The IAC motor is probably also causing your buzzing, since the ECU uses that to change the idle whenever the circuit is enabled and your transmission is shifted from Neutral to Park or Drive.

Not generally, but in this case I don’t think it’ll cause any harm. The idle simply won’t be properly controlled until you get the IAC fixed.

Those are my guesses. I’m sure you’ll get others.
Oh, and for the record, the item I’m alluding to is NOT a transmission solenoid. .I believe that to be a bad guess.

Thanks for the reply. IAC is something that is engaged even when car is off? Engine not running? Because the sound is there when engine is off and I shift gears, so it has to be purely electrical.

Also the rev in RPM does not happen every time when I shift to park, only sometimes, also seems to happen sometimes if I shift from Reverse to Drive (going through neutral).

If Im idling and turn on the A/C then the car compensates appropriately and there is no rise or loss of RPM the needle stays where it was, so whatever is responsible for that is working fine.

Also do you know if on 2003 Lancer ES if IAC is on the left or right side of the engine? The sound is coming from the right side.

if it is the IAC, how much would replacement cost and what are the consequences of keeping driving like this? Worse gas milage or anything like that?

I understood you to say that the engine was off but the key was ON. In this configuration, the ECU is enabled as are the circuits that drive the IAC motor.

Here are some prices from one supplier:,2003,lancer,2.0l+l4,1417238,fuel/air,idle+air+control+(iac)+valve,6072
You may want to do a bit of shopping.

It’ll be mounted to the throttle body. I’m not sure on that engine which side of the car that’s on.

Thanks! If IAC was the issue would it manifest somehow while actually driving? Like if I pull up to a stop light and stop there are no issues at all, generally while normally driving there are zero issues and everything seems normal. Only that weird sound switching from P or N and sometimes rev in RPM when shifting from R to D or from D to P.

Not necessarily.
However I’d get a friend’s help and see if the sound you describe is coming from the IAC when the conditions you describe are in effect. Have the friend shift with the engine off and the key ON and see if with your head under the hood you can tell where the sound is coming from.

I cannot say I KNOW it’s the IAC, I’m saying that is IMHO a likely suspect. Verify it before changing any parts.

I’m just amazed you got out of AAMCO without your transmission being disassembled and a ransom being demanded for putting it back together.


lol … thanks for the chuckle :wink:

I agree.
AAMCO is an acronym for All Automatics Must Come Out. :relaxed:


Well unfortunately without a CEL Im a bit reluctant to take the car elsewhere and pay $100+ dollars for a diagnostic. Since its most likely any mechanic will be just guessing about what the problem is and possibly changing parts that arent needing changing.

Like I said I took it to two different AAMCO shops completely independent shops and both said its likely a solenoid in the transmission.

I can almost guarantee that if you use AAMCO you will end up with a complete transmission charge.


I ended up unplugging the IAC completely from power and tying it and the sound is still there, so it cant be the IAC. I did the same thing with Air Intake sensor since its kind of in the same area just to make sure that wasnt it.

Lancer… is that the make or model? Is there a make or model that’s missing?

Its a 2003 Mitsubishi Lancer -