Circuit Description
The PCM uses the TP, the BARO, the IAT and the engine RPM in order to calculate an expected Mass Airflow rate. The PCM compares this value to the Mass Airflow value and the speed density calculation in order to verify the proper throttle operation.
Conditions for Running the DTC
| • | DTCs P0601, P0602, P0604, P0606, P1515, P1516, P1517, P1518, are not set. |
| • | DTCs P1120, P1220 and P1221 are not set at the same time or DTCs P1120 and P1220 are not set at the same time. |
| • | The engine operates longer than 1 second. |
| • | The engine speed is greater than 500 RPM. |
Conditions for Setting the DTC
| • | The PCM detects that the difference between the actual airflow (MAF) and the Speed Density calculated airflow is greater than expected. |
| • | All of the above conditions met for less than 1 second. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the Malfunction Indicator Light (MIL) when this diagnostic runs and fails. |
| • | The Reduced Engine Power message displays on the driver's information center. |
| • | The PCM records the operating conditions at the time during which the diagnostic fails. The PCM stores this information in the Freeze Frame and/or Failure Records. |
| • | If no other TAC System DTCs are set, the TAC System operates in Reduced Engine Power mode, and this DTC will be stored. If certain TAC System DTCs are set at the same time, the TAC System either defaults to a more tightly restricted mode of operation if the TAC determines that limited safe operation is possible, or the TAC commands the engine to shut down. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns the MIL OFF after three consecutive drive trips during which the diagnostic runs and does not fail. |
| • | A last test failed (Current DTC) will clear when the diagnostic runs and does not fail. |
| • | A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures. |
| Important: The clear DTC info function may have to be performed twice in order to clear a Throttle Actuator Control System DTC. |
| • | Clear the MIL/DTC information with a scan tool. |
Diagnostic Aids
Important:
• Remove any debris from the PCM\TAC module connector surfaces before
servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets
when diagnosing/replacing the modules. Ensure that the gaskets are installed
correctly. The gaskets prevent contaminate intrusion into the PCM\TAC
modules. • For any test that requires probing the PCM or a component
harness connector, use the Connector Test Adapter Kit J 35616
. Using this kit prevents damage
to the harness/component terminals. Refer to
Using Connector Test Adapters
in Wiring Systems.
| • | Inspect the throttle blade for being broken, bent, or missing. |
| • | Inspect the TP sensor for proper installation. A sensor that is mis-aligned sets this DTC. |
| • | When the TAC module detects a problem within the TAC System, more than one TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual problem may correct more than one DTC. Keep this in mind when reviewing captured DTC info. |
| • | For an Intermittent condition, refer to Symptoms . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Physically/visually inspect the throttle body assembly and correct any problems that you observe. Manually move the throttle blade from closed to Wide Open Throttle (WOT). You should not need to use excessive force. The throttle blade should move smoothly through the full range and should return to a slightly open position on its own.
-
When the TAC module detects a problem within the TAC System, more than one TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual problem may correct more than one DTC. Keep this in mind when reviewing captured DTC info.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||||||
2 | Is DTC P0101, P0102, P0103, P0107, P0108, P0112, P0113, P1111, or P1112 set? | -- | Diagnose these DTCs first | |||||||||
|
Caution: Turn OFF the ignition before inserting fingers into the throttle bore. Unexpected movement of the throttle blade could cause personal injury. Important: If any of the conditions listed below exist, replace the throttle body. Inspect the throttle body for the following:
Did you find and correct the condition? | -- | Go to Diagnostic Aids | ||||||||||
4 |
Does the scan tool indicate that this diagnostic ran and passed? | -- | ||||||||||
Select the Capture Info option and the Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK |
