Circuit Description
The throttle actuator control (TAC) module contains data which is essential for proper TAC system operation. The TAC module continuously tests the integrity of this data. When the TAC module is unable to write or read data to and from random access memory (RAM) or when the TAC module is unable to correctly read data from the flash memory, or when an internal TAC module processor fault is detected, this DTC sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P2108 Throttle Actuator Control (TAC) Module Performance
Conditions for Running the DTC
| • | DTC U0107 is not set. |
| • | The ignition switch is in the crank or the run position. |
| • | The ignition voltage is greater than 5.23 volts. |
| • | DTC P2108 runs continuously once the above conditions are met. |
Conditions for Setting the DTC
| • | The TAC module determines that an internal data test did not pass. |
| • | The above condition is present between 0.8-60 seconds. |
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
| • | Ensure the starting and charging systems are operating properly. Low system voltage can cause this DTC to set. |
| • | Inspect the TAC module connectors for signs of water intrusion. When water intrusion occurs, multiple DTCs could be set with no DTC circuit or component conditions found during diagnostic testing. |
| • | 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 that run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting the components during testing may set additional DTCs. Keep this in mind when reviewing the Capture Info. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View References: Powertrain Control Module Connector End Views , or Engine Controls Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 | Replace the throttle actuator control (TAC) Module. Refer to Electronic Throttle Actuator Control Module Replacement . Did you complete the replacement? | Go to Step 3 | -- |
3 |
Does the DTC run and pass? | Go to Step 4 | Go to Step 2 |
Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK | |
