Circuit Description
The Throttle Actuator Control (TAC) Module contains data which is essential for proper TAC System operation. The TAC Module continuously checks the integrity of this data. When the TAC module is unable to write or read data to and from RAM or the TAC module is unable to correctly read data from the flash memory or an internal TAC module processor fault is detected, this DTC will set.
Conditions for Running the DTC
| • | DTC P1518 not set. |
| • | Ignition switch is in the crank or run position. |
| • | Ignition voltage greater than 5.23 volts. |
Conditions for Setting the DTC
| • | The TAC Module determines that an internal data test did not pass. |
| • | All above conditions met for less than 1 second. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the MIL and the Reduced Engine Power light will be on when this diagnostic fails. |
| • | The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and/or Failure Records. |
| • | If no other TAC System DTCs are set, the TAC System will operate 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 will either default to a more tightly restricted mode of operation if it is determined that limited safe operation is possible, or command engine shut down. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL off after three consecutive drive trips that the diagnostic runs and does not fail. |
| • | A History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | A last test failed (Current DTC) will clear when the diagnostic runs and does not fail. |
| • | PCM battery voltage is interrupted. |
| Important: The clear DTC info function may have to be performed twice in order to clear a Throttle Actuator Control System DTC. |
| • | Using a scan tool. |
Diagnostic Aids
| • | Refer to Intermittents under service category Symptoms . |
| • | If a repair is completed and the DTC was cleared using a scan tool on the same ignition cycle, the default action will not clear until an ignition cycle has occurred. |
Test Description
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
2 | Replace the TAC Module. Refer to Electronic Throttle Actuator Control Module Replacement . Is the action complete? | -- | -- | |
3 |
Does the scan tool indicate that this diagnostic ran and passed? | -- | ||
4 | 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 |
