Throttle Body - Relearn Procedure

The ECM stores values that include the lowest possible TP sensor positions (0%), the rest positions (7%) and the return rate of both springs. These values will only be erased or overwritten if the ECM is reprogrammed or if a throttle body relearn procedure has been performed. NOTE: If the battery is disconnected, the ECM will immediately perform a throttle body relearn procedure upon key-up.

A throttle body relearn procedure will be performed anytime the ignition is turned On with the engine Off for longer than 29 seconds when the following conditions have been met:
^ Engine speed is less than 40 rpm
^ Vehicle speed = 0 mph
^ ECT is between 5 and 100°C (41-212°F)
^ IAT is greater than 5°C (41°F)
^ Accelerator pedal angle is less than 15%
^ Main relay voltage is greater than 10 volts

After 29 seconds, the ECM will move the throttle plate from the rest position to full closed, then to around 10% open. This will take about 2-3 seconds. If any faults occur in the TAC system, a DTC will be set. At the start of this procedure, the Scan tool TAC LEARN COUNTER parameter should display 0, then count up to 11 after the procedure has been completed. If the counter did not start at 0, or if the counter did not end at II, a fault has occurred and a DTC should be set.