P1516

DTC P1516

Circuit Description

The commanded throttle position is compared to the actual throttle position based on accelerator pedal position (APP) and possibly other limiting factors. Both values should be within a calibrated range of each other. The powertrain control module (PCM) continuously monitors the commanded and actual throttle positions. This DTC sets if the values are greater than the calibrated range.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P1516 Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance

Conditions for Running the DTC

* The ignition is ON.
* The ignition voltage is greater than 8 volts.
* The system is not in the Battery Save mode.
* The engine is running.
* DTC P0068 is not set.
* DTC P1516 runs continuously when the above conditions are met.

Conditions for Setting the DTC

The difference between the predicted and the actual throttle position is more than a calibrated amount for more than 0.5 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.
* A message center or an indicator displays Reduced Engine Power.
* Under certain conditions the control module commands the engine OFF.

Conditions for Clearing the MIL/DTC

* The PCM turns OFF the MIL after 3 consecutive drive trips that the diagnostic runs and passes.
* A History DTC clears after 40 consecutive warm-up cycles in which there are no failures reported of this diagnostic or any other emission related diagnostic.
* The scan tool clears the MIL/DTC.

Diagnostic Aids

* The throttle valve are spring loaded to a slightly open position.
* The throttle valve should be open approximately 20 percent. This is referred to as the rest position.
* The throttle valve should not be completely closed nor should they be open any more than the specified amount.
* The throttle valve should move open and to the closed position without binding under the normal spring pressure.
* The throttle should NOT be free to move open or closed WITHOUT spring pressure.
* Replace the throttle body if any of these conditions are found.

Important: Operating the throttle blade with the Throttle Blade Control function of the scan tool may cause additional DTCs to set. Do not attempt to diagnose DTCs set during this function.

* The scan tool has the ability to operate the throttle control system using Special Functions. Actuate the throttle valve using the throttle blade control function located in the throttle actuator control (TAC) system menu. This function will operate the throttle valve through the entire range in order to determine if the throttle body and system operate correctly.
* Inspect for the following conditions:

- Use the J 35616 Connector Test Adapter Kit for any test that requires probing the PCM harness connector or a component harness connector.
- Poor connections at the PCM or at the component-Inspect the harness connectors for a poor terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections in Diagnostic Aids for the proper procedure. Component Tests and General Diagnostics
- If the condition is intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Diagnostic Aids. Component Tests and General Diagnostics

Test Description

Step 1 - Step 8:

Step 9 - Step 15:

Step 16 - Step 27:

The numbers below refer to the step numbers on the diagnostic table.
8. The throttle valve is spring loaded in a slightly open position and should move in either direction without binding. The throttle valve should always be under spring pressure.
11. When the ignition is turned ON, the PCM operates the throttle control motor to verify the integrity of the system prior to start-up. This can be seen by the momentary flash of the test lamp as the ignition is turned ON.