Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
There is a throttle learn procedure, that must be done after a throttle is replaced. Below are the instructions.
The engine control module (ECM) learns the idle position of the throttle plate to ensure the correct idle. Any time the throttle body is cleaned or replaced, the ECM must learn the new throttle position. The idle may be unstable or a DTC may set if the throttle position is not learned.
Important: Do not perform this procedure if DTCs are set. Refer to Diagnostic Trouble Code (DTC) List - Vehicle .
Important: During the drive cycle the check engine light may come on with idle speed DTCs. If idle speed codes are set, clear codes so the ECM can continue to learn.
Just tried the idle in PARK. The engine speed is now at 2500 RPM. Idling twice at 3 min with 60 second OFF intervals did not work. Drove the car for 10 KM. Idle seems to set at 680 RMP when stopped with brakes applied with trotter at 5% showing on data reader. As soon as brake is released and the vehicle starts rolling, the throttle opens to 10-12% and RPM goes up to 1000. At the final stop, placed the vehicle in park and the RPM stabilized at 800 (still bit high). When I tapped the accelerator, the engine speed went back up to 2500 rpm. Am I doing something wrong?
None appeared during the whole procedure..
What was the system doing that you needed to replace the throttle body in the first place?
Throttle position sensor was bad, and since the TPS is a part of the throttle body, the whole TB had to be replaced.
Ok. Try performing a capacitor discharge (remove battery cables, hold together for 10 seconds) and perform the relearn again. The App sensor is good then?
APP sensor seems to be ok, since the car was working fine before the new TB was put in. I will attempt the discharge. I have read other suggestions, which recommend just simply driving the car for about 30 minutes. Do u think a longer trip may be beneficial, since I've only driven for about 10 minutes.
It would be worth a try. Honestly, I have not seen one of these fails yet, so I am going by what the manual says.
Great!!! Have a great day!!
On my third restart, the problem came up again. Here is what happened:I drove about 60 KM. Every time I would stop at a traffic light, the RPM would first settle at 1000, then slowly go down to 680. As soon as I let go of the brake pedal, the car slowly starts rolling on idle. As it hits 5 km/h, the RPM jump to 1000 and the car begins to accelerate without my input.I stopped and took off the positive battery terminal, then plugged it back on. Started the car, the RPM went to 2000, then within 10 seconds came back to normal 680. As soon as I gently tap the accelerator, the RPM goes to 2500-3000 and stays like that. I've had it running like that for about 10 minutes and with no change.What do you think may be the problem? Faulty TB? I thought that maybe the APP is to blamed, but it worked fine before I replaced the TB.
I agree that the App should not be the issue. Let me do more looking.
I don't think I can do these mods with my computer. I have a superchips programmer which can give me readouts of various sensors, but I doubt that it would allow me to do these calibrations. Are you familiar with these?
I found a bulletin that says the ECM may need the throttle reset in the ECM.
It is an oiled filter from K&N Part 63-3058 on a Cold Air Intake. It has last been cleaned and oiled about a month ago.
Ok, clean the mass air flow sensor. Often too much oil will cause a false reading and most people over oil the filter.
No, this is likely a dealer or shop only scan tool procedure.