Firstly, check the vehicle for any pre-existing trouble codes and make the appropriate repairs. Inspect the PCB system. Inspect the engine for any damaged hoses that could cause a vacuum leak. Special attention should be given to the PCV system, oil dipstick, and filler cap seals for damage. Disconnect the negative battery terminal for 30 seconds to reset the onboard computer. Do not perform the relearn if the service engine soon light is on and codes related to the mass airflow sensor, manifold absolute pressure, or incorrect idle speed are found. If everything is in order, we can begin.
First, bring the engine to normal operating temperature, 160-203°F or 70-95°C. Second, make sure that ignition timing is at the recommended manufacturer’s specifications. Third, turn off all accessories such as the air conditioning, rear window defogger, radio, and heater blower to prevent a load on the engine which would cause erroneous positioning of the throttle plate. Finally, make sure the front wheels of the vehicle are in the neutral position pointing straight ahead. We are now ready to perform the required relearn procedure.
Make sure the accelerator pedal is fully released. Turn the ignition switch on without starting the engine for at least 2 seconds. Turn the ignition switch off for at least 10 seconds. Again, turn the ignition on for at least 2 seconds. Turn the ignition off for at least 10 seconds. This action will inform the computer on the new release position of the accelerator pedal and the closed position. Now that this is done, we can move on to the next step. Please make sure to follow these next instructions precisely as every action is performed within a few seconds. Turn the ignition switch on and wait 3 seconds. Immediately after the 3 seconds, the accelerator pedal must be pressed and released 5 times within 5 seconds. Wait 7 seconds and fully press the accelerator pedal and hold for approximately 20 seconds until the check engine light stops blinking and stays on. Within 3 seconds after the check engine light stays constantly on, release the accelerator pedal. Now start the engine and let it idle. After 20 seconds, rev up the engine a couple of times to ensure idle speed is within specifications. If the relearn was unsuccessful, turn the key to the off position wait 60 seconds and restart the process.
There is no IACV these days, the whole throttle body is now electronic, the svc manual in chptr EC gives you the relearn procedure for both idle and position. read it carefully, it states it must be followed exactly or you'll have to start over, again and again