P1516

CIRCUIT DESCRIPTION
The predicted Throttle Position (TP), based on the Accelerator Pedal Position (APP) and possibly on other limiting factors, is compared to the actual throttle position. The 2 values should be within a calibrated range of each other. Both the PCM and the TAC module redundantly monitor the predicted and actual throttle positions. This DTC sets if the PCM detects an out-of-range condition between the predicted and the actual throttle positions.

CONDITIONS FOR RUNNING THE DTC
^ DTC P1518 is not set.
^ The ignition switch is in the crank or run position.
^ The ignition voltage is greater than 5.23 volts.
^ The Throttle Actuator Control (TAC) system is not in the battery saver mode.

CONDITIONS FOR SETTING THE DTC
^ The TAC module detects that the predicted and the actual throttle positions are not within a calibrated range of each other or the PCM, and the TAC cannot determine whether the throttle position or both TP sensors are invalid.
^ All of the above conditions met for less than 1 second.

ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
^ The control module commands the TAC system to operate in the Reduced Engine Power mode.

OR

^ Under certain conditions the control module commands the engine OFF.
^ The message center displays Reduced Engine Power.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
^ Use a scan tool in order to clear the MIL and the DTC.

DIAGNOSTIC AIDS
^ Inspect the TAC module connectors for signs of water intrusion. When this occurs, multiple DTCs could be set without circuit or component conditions found during diagnostic testing.
^ Ensure that the starting and charging systems are operating properly. Low system voltage can cause this DTC to set.
^ When the TAC module detects a condition within the TAC system, more than 1 TAC system-related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Be aware of this if you review the stored information in Capture Info.
^ For an intermittent, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-8:

Steps 9-18:

The numbers below refer to the step numbers on the diagnostic table.
7. If the TP Indicated Angle does not follow the movement of the throttle blade, and if TP sensor DTCs are not set, there is a mechanical condition with the throttle shaft or the TP sensor.
18. When the TAC module detects a condition within the TAC system, more than 1 TAC system related DTC may set. This condition is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Be aware of this if you review the stored information in Capture Info.