how to adjust idle speed on 2007 toyota corolla
You can't. The idle speed is sent to throttle body from the ECU from several inputs, the MAF, Etc. Some sensor is sending a false signal to ECU or has failed. You need an OBDII scan, no matter if the Check Engine Light is lit up or not, that hopefully point you to what sensor is fooling the ECU. Your car has drive-by-wire, or electronic throttle control so there is no adjustment as on a cable. My Corolla idles at about 900 to 1000 warm, 1200 cold, so it's not that bad. Needs attention yes but not critical OR--- You have a vacuum leak somewhere. If you are a DIY guy use an UNLIT propane torch and wave it around the intake and see if it idles even higher... and look for any vacuum hoses disconnected or broken
You can try cleaning the IAC and throttle body. Just might work https://www.youtube.com/watch?v=mfauGoGXCmo https://www.youtube.com/watch?v=mGs0j5FT220
I've been toying with this problem for a few months with all previous and current answers: Check engine mounts; Check vacuum hoses and air manifold for leaks; Clean throttle body; Clean and test idle air control. No change to idle speed or engine vibration. No ECU problems indicated. By the many member entries with the same or similar problems, I am beginning to believe that this is a cronic and non-adjusting or reversing problem, and "normal behavior" of Toyota cars. A friend with a 2004 Camry has been battling the same problem (high idle and engine vibration) for a few years with no solution from a local Toyota dealer or local repair shop. My question now is, "Can the accelerator pedal sensor positioning be adjusted to lower/raise the idle speed?" Anybody?
No. It can not. I highly wish somebody else will chime in on this thread and either agree or say I am wrong and explain. But the 'drive by-wire' electronic throttle is a rheostat. Non adjustable But as stated. my '06 Corolla, which is identical except trim same engine idles at 900 to 1000 warm. Is your car warming up to middle of gauge? I am beginning to think it's stuck in open loop, when the 02 signals are ignored by ECU for cold start, but not going to closed loop when warm - IF- If that is the case would explain it - the ECU 'thinks' the car is cold
Sounds like all the usual bases have been covered here. I can think of one more though. Reflash the computer with more current software. It's possible that, since this sounds like a reoccurring problem with some Toyotas, a sensor has shifted value. But not enough to trigger the check engine light. Another thought that comes to mind is the battery. Has it recently been replaced or disconnected for some reason. On my '08 Grand Marquis (different car, I know) if the battery is disconnected a first time start up procedure must be followed or the idle can be excessively high due to the mispositioning of the IAC (Idle Air Control) valve. Excessive output of the alternator can result in a high idle speed as well. But you'd have overcharging of the battery as evidenced by gassing (foul odor near the battery) and excessive water usage. Frequent light bulb burn outs are a sign of overcharging as well. HTH. -Jim
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