Subaru ecu I Have a 2003 Subaru Baja 2.5 litre Automatic.That suddenly stopped running when I was pulling into a parking lot and is giving me a P0122 error code (Throttle position sensor circuit low input). It will sometimes start idle high for a few minutes then start to idle rough and die. I replaced the throttle position sensor same thing happens. While adjusting the position sensor with the key in the ignition on position I hear a humming coming from underneath car. and when I attempt to start it will flash The AT oil temp light on dash. Any thoughts or ideas? Thanks, Badchicken425 I reset the ecu and got it started it idled rough then smoothed out after time but I could not accelerate otherwise it would die. the error code and transmission light have now vanished

Jeff Barton

• 520 Answers
• Posted on Jul 14, 2009

SOURCE: Driveshaft Lubrication Points 1996 Subaru Legacy

There are no greases zerks or lube points on that model .You actually aren't moving anything while in this state. I have seen exhaust components cause this if there is any contact to chassis or rubber mounts missing.The engine vibration through the exhaust system can resonate noise.

Mike Butler

• 6674 Answers
• Posted on Aug 23, 2009

SOURCE: 2004 subaru forester, 99,000 miles. Check engine

Drop in to an Autozone, or Pep Boys, or similar big parts store & they will usually scan for codes free. This will hopefully eliminate all the guess work, or at least point everyone in right direction for better diagnosis. If not obvious from codes what the problem is, get back to us and we'll help you out.

Testimonial: "Thanks for the great suggestion . I'll have Autozone read the codes on Monday. Thanks again!"

SOURCE: having trouble starting my 2003 subaru wrx

The sensor is not in your key. It is in the Key Fob, unless your car is not equipped with keyless entry. If there is no key fob than your car is not equipped with vehicle immobilization.

SOURCE: subaru impreza rs 2.5 insanely high idle

check you dont have a split in the corrugated pipe from the maf to the swirl chamber (the big black plastic tank attached to the inlet manifold) or a leak into the intake somewhere, doesnt have to be a small vac tube.

Also you may have a sticking TB butterfly as my learned friend suggested.

Dan Martin

• 252 Answers
• Posted on Jul 18, 2010

SOURCE: 1998 subaru rs impreza 2.5

Hi

Usually a vacuum leak will make the idle bog down rather than speed up, even if the ECU is compensating. It will be rough, but as you say, it's fine through the revs.

This leads me to think the PCV (postive crankcase valve) is not connected or is leaking. This raises the idle, although the ECU will suspect the IAC to be the problem. Check the PCV valve first.

Check the MAF sensor for dirt too.

Another point to make is the throttle body might be clogged/dirty. Get the intake manifold off again and clean it with petrol/carb cleaner and a toothbrush, check the condition of the rubber seals, if they are gunked up, the air speed will increase, causing a high idle. Check the exhaust manifolds for any build up/rust.

Finally, when were the O2 sensors last changed? If recently, are they the right way around? If not recently, try those, but make this the last resort as they can cost a lot.

I hope I have covered every eventuality as I can see how annoying this is for you. As you already mentioned, reset the ECu after each attempt.

Good luck, fire any questions back if you need.