DTC P1526: TP Sensor Learn Not Done After Reprogramming: Description

The Throttle Actuator Control (TAC) module contains a direct current actuator motor controlled by the ECM used to move the throttle plate (in either direction) and two throttle position sensors to determine throttle plate position. The throttle plate is held at a 7 percent rest position to a mechanical stop by a constant force return spring. This spring will hold the throttle plate to the stop when there is no current flowing to the actuator motor. There is another return spring, which creates constant force on the throttle plate only when the throttle plate is moved towards the full closed position. The ECM will monitor both the actuator motor and TP sensors for circuit faults, as well as check to make sure both springs can return the throttle to the 7 percent position no matter where the throttle plate remains. The ECM will go through a throttle relearn procedure 29 seconds after the ignition is turned on with the engine off as long as certain conditions have been met. During this learn procedure, the ECM will move the throttle from the rest to full closed position, then to around 14 percent. During this period, the TP sensors lower limits, rest position of the TP sensors, the actuator motor force to overcome both spring pressures as well as the return rates of both springs are learned. If any of these parameters are out of range, a DTC will be set. DTC P1526 will set if the throttle has not been learned after the ECM has been reprogrammed; or the learned rest position TP values do not match the stored learned values within a certain range.