2000 S40 downshifting

bryan59 · Post by **bryan59** » 16 Jan 2013, 13:21

Hi everyone,hoping for some input for my wifes 2000 S40.
While driving, the car will randomly downshift without warning. She usually has to pull over and shut of the car for about 5 minutes. She than can continue on her way. She has said, sometimes, when she turns the car off for the 5 minutes and restarts the car will idle at around 3000 rpm. She again turns off the car and it will usually idle normally after that, until the next time it downshifts. Until last week, it has been a year of driving with no problems. Has happened twice in the past week again.
Had it scanned for codes, and none came up.
fluids are clean and full
I'm kinda stumped.

thx, bryan

keithatcpt · Post by **keithatcpt** » 21 Jan 2013, 07:54

Check the Idle air control valve. I don't know why or if it would cause downshifting, but the high idle could definitely be caused by the IAC valve.

musicman · Post by **musicman** » 21 Jan 2013, 10:27

i had an 850 with the exact same issue. Ended up being a faulty sensor, try hooking it up to an obd-ii. Auto Zone will scan for free. Very annoying, good luck, want to hear the results.

bryan59 · Post by **bryan59** » 08 Feb 2013, 08:49

Did the obd scan, nothing came up. Do you remember what sensor was faulty? \Thanks for the reply guys. I will definitely clean the IAC valve