View Full Version : Help!!! P0638

05-23-2010, 12:48 AM
Hello all,

I have 2006 Subaru Legacy Spec-b. In march of this year my wife and I were driving when our car when it faulted with a check engine/flashing cruise control light, and most noticeably; the car wouldn't rev more than 2000 RPMs (limiting our max speed to 10 mph). My car has been in and out of the Subaru Dealership for the past 2 months. Every time my car has gone in, a stored code of P0638 was present. The dealership has checked all the wire connections of my Electronic Throttle Control System, replaced my accelerator assembly, and replaced my throttle relay. I picked up my car (for the 7th time) on May 20th (2 days ago), and today my car faulted AGAIN!!!!!

Both the Subaru dealer and Subaru of America have told me they've done all they can do for my car, and they are unable to diagnose it because the car behaves itself when they have it. Basically they told me not to bring it back.

It is my understanding this problem is related to a mismatch in positions between the accelerator position and the throttle position.

Has anybody had this same error? If so, please help me out with some direction. I've already paid too much money to have a broken car, and cannot afford much more.

Thank you,


07-12-2010, 09:37 AM
i had one in my shop a few months back and i had to replace the ecm. im not sure for you but thats what i did here. good luck!