2006-2012 Toyota Idle Relearn Procedure
Modern vehicles, such as those manufactured by Chevy, work in unison with computer modules within the engine compartment. An idle relearn procedure must be performed if a computer, or chip, is replaced in the vehicle. An idle relearn procedure is a way to reprogram the vehicle's computer memory to idle at a specified RPM, or revolutions per minute. Without the programmed idle, the vehicle can run arbitrarily, resulting in unnecessary engine wear.
Chevy uses a simple idle relearn process. After you replace the computer chip, it will automatically reset itself when you turn the ignition key from the "on" position to the "off" position.
Blue Streak Electronics recommends to warm the engine after the idle relearn procedure, without use of the air conditioner.
After the engine is warm, switch the air conditioning on and off, and then put the transmission into the "drive" position. These actions complete the full idle relearn procedure. It is imperative that a technician verifies that the car's battery is fully charged. If power fails during a relearn procedure, the technician must reprogram the computer chip.
This article was written by the It Still Works team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information. To submit your questions or ideas, or to simply learn more about It Still Works, contact us.
Considerations It is imperative that a technician verifies that the car's battery is fully charged. About the Author This article was written by the It Still Works team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.See all 11 photos. Walk to the edge, look down, and you'll see heaps of brand-new throttle-position sensors, mass airflow meters, manifold-absolute-pressure sensors, manifold-air-temperature sensors, coolant-temperature sensors, oxygen sensors, idle-air control motors, knock sensors, and electronic control modules.
Among skeletons and empty wallets, a gentle stream flows around the discarded heaps of high-tech gadgets. We're not bashing on TPI cars, in fact, we love 'em for delivering massive amounts lb-ft of low- and midrange power while delivering fuel economy in excess of 18 mpg around town.
But you can visit TPI Gulch if something goes wrong and you attempt to repair your Corvette, Camaro, or Firebird without the proper resources. Fortunately, my trip into TPI Gulch was a brief one. In keeping with the low-buck theme, I removed, repaired, and reinstalled the engine myself, but instead of a clean startup and a tire-smoking drive-off, the darned SES light appeared for the first time in my ownership of the car.
Something was screwed up again. But what? Being a good car crafter, when I fixed the crank, I was very careful to completely document the engine removal process with no less than digital pictures so I could put the unfamiliar C4 back together just the way it left Bowling Green, Kentucky, 22 years ago. I practically wore out a pair of shoes running between the car and my home computer screen to review the pictures during the painstaking reassembly process.
The problem wasn't in the machine work either. The thing fired right up, and the oil-pressure gauge showed 65 psi. What's more, the sounded great at idle and drove like new at part throttle on surface streets. But at anything over half throttle, which is where Corvettes come to life, the motor would hiccup, the SES light would turn on, and the engine would turn into a pig.
Oh, it'd run up to its 5,rpm shift point, but it was laboring and sure didn't feel like net horsepower. Clearly it was in "limp home mode," a self-preservation tactic where the ECM triggers stinky-rich fuel metering and retards the spark curve to prevent damage.
Worse, the dash-mounted instantaneous fuel-economy readout showed single digits. With a fresh set of piston rings, I knew the obvious gas wash would quickly dilute the oil, making every mile traveled equal to 1, miles of wear. I parked it after two frustrating days of repeatedly disconnecting the battery to clear the codes and defeat the SES.
Having little experience with ailing EFI cars, I searched the Internet and quickly found out that everybody has an opinion. It's the computer, it's the knock sensor, it's the mass airflow meter MAFthe catalytic converter is clogged, the fuel injectors are bad, it's the oxygen sensor, it's the EGR valve, it's the fuel pump, it's Duntov's ghost.
But the thing I heard most was nightmare stories of how TPI cars can nickel and dime you to death. If I followed all the advice, I'd join the parts changers, spend more than a grand on dead-end leads, and end up in Gulchville. I braced myself for the decision to either cut my losses and sell the thing as a fatally flawed parts car or dig in and make the needed repairs. Having come so far, I dug in.
My first task was to read the trouble codes stored in the ECM. Wow, how easy is this?Before continuing, we recommend you clean your IAC valve. What you will need is a paperclip, torx screwdriver T to make adjustments and an accurate RPM gauge.
Start the car and let it warm to operating temperature. The down side to this is the heat emitted from the engine as you try to disconnect the IAC in the following instructions. But, the engine has to be warmed up. This terminal is part of a wiring connector located just underneath the dashboard, next to the steering column. A small plate is used to cover the connector and must be removed to gain access to the terminals.
Once the terminals are shorted, turn the ignition to the ON position without starting the vehicle. Wait 30 seconds. Start engine. Check the RPM gauge for the proper idle speed setting minimum air. This information can be obtained from Specifications, Tune Up Specs for any year you select. This is what needs to be turned to adjust minimum air or idle speed.
It comes from the factory with a protective metal cap over it. If the cap is still there, use a small punch to knock it out. Set the idle speed to specifications, rotating the torx screw clockwise to raise RPM, and counter-clockwise to lower RPM. Once again, the desired RPM and needle were highlighted for ease of viewing. Once the idle RPM is set, turn off the engine.
Reconnect the connector onto the IAC.
Remove the ALDL jumper. Idle speed is now once again governed by the ECM, but your idle should be smooth and steady at about RPM in Drive for unmodified cars. Before going too far, you should adjust your Throttle Position Sensor TPS if any adjustments were made to the idle speed. If you set a Check Engine light by having the IAC disconnected, ensure the engine is off, disconnect the negative battery terminal and wait 5 minutes. This should clear the ECM of all trouble codes. Skip to content.Remember Me?
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If you go to the end of the log, the TPS is at zero and the car is in park. My IAC count is arount What should it be at and how do I adjust this? It should be at with a cammed car. Your throttle position will now be reset to 0 degrees and about. Any higher can put you into the wrong fueling cell. HP Tuner tuned by me. I don't think there's anything wrong with IAC at It's less than half of full scale.
The thing that will bring IAC down aside from more bypass air is more spark and proper fueling. Fueling is going to be bugged by O2 sensor fidelity cold from headers and airflow VE fidelity, tending to overfuel after a cam swap. But there's nothing wrong with IAC counts in itself. Originally Posted by jimmyblue.
IAC counts are adjusted by moving the set screw in the throttle body or enlarging the hole in the throttle body blade. Allowing more airflow into the engine by enlarging the hole or opening the blade with the set screw will reduce IAC counts.
The trick to using the set screw is having to reset your TPS after you make the changes. Opened it up, and a lot better. Originally Posted by ws6ick. Mine is not surging. If you say IAC count is good then I am leaving it alone. How do I get my scanner to read the throttle position voltage?By using this procedure you can obtain the proper adjustment between the throttle positioning sensor, distributor timing and the throttle body accelerator cable. Adjusting these components will give you the smoothest possible idle and the correct factory settings for your car.
You may purchase an AB jumper plug at your local parts store, but a simple jumper wire is all you need! Turn on the ignition switch without starting the car. You should hear the cooling fan begin to run and the check engine soon light should start to flash. After about 45 seconds with the key on unplug the idle air control solenoid.
Remove the ALDL jumper wire at this point. Unplug the tan and black distributor wire located on the driver side of the car beside the wiper motor.
Idle Relearn Procedures for a Chevy
This is the wire that sends the distributor to standard timing when the car is in open loop. Start the engine and adjust the timing to 6 degrees. When looking at the timing tab you will see a large V in the tab. This V is 0 degrees; count over three marks to the passenger side to obtain 6 degrees of timing. If the marks are not visible, 6 degrees is the first v toward the passenger side. The factory timing and settings for your car is located on a label located on the driver side of the fan shroud and it should be 6 degrees.
The car may try to stumble and fall while doing this, but get it as close to as possible. Re-connect the IAC connector and the distributor wire. Set the throttle positioning sensor voltage. Many times this is confused with 5. This is not correct and you should make sure the voltage is within the range mentioned first. To know what the setting is on your sensor you will need to purchase a voltage ohms meter and test across the black and dark blue wires located in the connector.
You must have the engine key in the on position to test the adjustment voltage and not running. We have a connector available part number for testing which will keep you from piercing your wires or you can probe the wires with your ohms meter. When you are finished setting the throttle sensor voltage you will need to erase the code 42 from your ECM that will set by having the distributor bypass wire unplugged.Couple months ago corresponding with one of the FiTech reps he provided me with a IAC adjustment instructions that I haven't seen before.
These ones take into account adjustments of both the front and rear butterflies. There are a few threads going on in regards to adjustment of secondaries.
I am copying here the instructions as I received them. I followed this procedure and it worked well. Didn't completely eliminate my fluctuating idle issue but it made an improvement. One thing I want to make sure is that the IAC is set correctly and that you were adjusting both throttle blades front and rear using both adjustment throttle screws. It is commonly done that this is set using only the front throttle screw and if it is not set with the back it can create all types of issues.
Here is the procedure to do that. Disconnect the throttle peddle from the throttle body, so we know it is not moving or holding the throttle. Unscrew both front and rear adjustment screws so they just come off of the pivot arm stop.
This will set the blades close enough to start and warm up for final adjustment. We just want the engine to idle, if it is high that is ok until it warms up if it is low and wont idle go in a small amount on both screws until it will idle.
Turn the key on do not start, at this point we want to clear the leaned data that the car has learned previously this way we can have a clean slate when we start. This will erase all leaned data but will not change any of your base settings. Turn the key off for 30 ish seconds. Start engine and let it warm up to degrees F then look at the IAC steps on your dashboard. With the engine running and the temp at or above adjust accordingly.
If the IAC is above 10 you will screw in both screws equally until the IAC steps falls below 10 but does not sit on zero. If the IAC steps are staying on Zero and the idle is above the desired setting you will unscrew both screws equally until the IAC jumps back and forth from a number under 10 but not staying on zero and the idle is at your target RPM.
While you are making your fine adjustments keep an eye on the TPS value, if it goes above 0 shut the engine off and let it sit for seconds.
Continue with the throttle blade adjustment. Let us know if you have any issues or questions. Thank you for this. I found a very helpful youtube video from a bronco guy in Nashville about the FiTech, but his model must only have had front blade adjustment back then? After trying this and spending time adjusting both blade sets simultaneously, I have it bouncing from regularly now. This is a very logical procedure.
I wonder why it took Fitech so long to come out with it. My car seems to idle fine setting it the original way. Do you think there is any point resetting it this way? A lot of people have posted that they have issues with the adjustment of the rear blades. This procedure takes care of it. In my case, even before I followed this procedure, I had an issue where the rear butterflies would stay open slightly in idle, which left the idle high until they finally closed.
This was happening because the rear set screw was not topping against the rear blade's rod so it left "play" in the system, which caused the butterflies to stay slightly open in idle. Forum Members Activity Login Register. June 22,pm. Quote from tony-muscle on June 22,pm. Click for thumbs down. Quote from mlrtyme on June 22,pm. June 23,pm.What you will need for the following procedure is carburetor cleaner and a wrench big enough to remove the IAC valve.
Ensure your ignition if OFF. Remove the connector to the IAC valve, located right below the Throttle Position Sensor TPS on the left side of the throttle body as you are looking at it from the front of the car. Using a wrench, remove the IAC valve by turning it counter-clockwise loosen and remove the valve. You can use a soft brush like a toothbrush to help with the cleaning. Generally, carburetor cleaner adds enough coating to the valve, so WD may be a little overkill.
Before reinstalling the IAC valve, measure the distance that the valve is extended, from the motor housing to the end of the cone. You should use a new gasket when possible. If the valve exceeds the specified measurement, press firmly on the valve to retract it. Reinstall the IAC valve, reconnect the IAC connector and reassemble all components removed to gain access to the IAC valve air intake snorkel assembly, hoses, vacuum lines, etc.
If you removed the air intake, ensure you reconnect the MAF sensor if equipped. You should be good to go.
If you need to adjust your minimum air idle speedclick here.
FiTech EFI Tuning Forum
Any adjustments made to the idle speed, should be followed by adjusting your throttle position sensor TPS. I will try to follow up with some additional images in the days to come. Skip to content.