Circuit Description
The commanded throttle position (TP), based on accelerator pedal position (APP), is compared to the actual throttle position. The TP values should be within a calibrated range of each other. The throttle actuator control (TAC) module monitors the commanded and actual throttle position. If the TAC module detects that the commanded and actual throttle positions are not within a calibrated range of each other or the TAC module or the powertrain control module (PCM) cannot determine throttle position or if both TP sensors are invalid a message is sent to the PCM across serial data and DTC P1516 is set.
Conditions for Running the DTC
| • | The ignition is in the crank or run position. |
| • | The system is not in battery saver mode. |
| • | The ignition voltage is more than 5.23 volts. |
| • | The communication between the TAC module and the PCM must be valid. |
Conditions for Setting the DTC
| • | The TAC module detects that the commanded and the actual throttle positions are not within a calibrated range of each other. |
| OR |
| • | The TAC module or the PCM cannot determine throttle position. |
| OR |
| • | Both TP sensors are invalid. |
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 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. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
| • | Inspect for mechanical conditions or for binding that may be temperature related. Components may not move freely in extreme heat or cold due to the presence of contaminants or ice formation. |
| • | If the condition is intermittent, refer to Intermittent Conditions . |
Test Description
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Both TP sensor DTCs active at the same time will result in DTC P1516 also set. It is necessary to diagnose both sensor faults individually.
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A DTC P1518 set along with a sensor DTC may indicate a sensor fault, refer to the sensor diagnostic table first.
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views and Engine Controls Connector End Views | ||||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||||
2 | Is DTC P2108 also set? | -- | Go to Step 3 | |||||||||
Are DTCs P0120 and P0220 both set? | -- | Go to Step 4 | ||||||||||
Is DTC P1518 set along with one of the following DTCs?
| -- | Go to Step 6 | Go to Step 5 | |||||||||
5 | Is DTC P1518 also set? | -- | Go to Step 8 | |||||||||
6 | Diagnose the appropriate sensor DTC first. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 7 | ||||||||
7 |
Does the throttle position (TP) sensor 1 and TP sensor 2 angle increase to near the specified value as the pedal is depressed and decrease as the pedal is released? | 100% | Go to Diagnostic Aids | Go to Step 8 | ||||||||
8 | Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement? | -- | Go to Step 9 | -- | ||||||||
9 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 10 | ||||||||
10 |
Important: Be aware that repairing 1 individual condition may correct more than 1 DTC. Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||||
