The throttle actuator control (TAC) module contains data which is essential for proper electronic throttle control (ETC) 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 random access memory (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 communicated to the powertrain control module (PCM) across serial data and this DTC sets.
• | The ignition is in the crank or run position. |
• | DTC P1518 is not present. |
The TAC module determines that an internal data test did not pass.
• | 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/Failure Records. |
• | 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. |
Important: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing/replacing a component. Verify that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |
2 |
Important: If any other DTCs are set, refer to the appropriate DTC first for further diagnosis. Replace the TAC module. Refer to Accelerator Pedal Position Sensor Replacement . Did you complete the replacement? | Go to Step 3 | -- |
3 |
Does the DTC run, and pass? | Go to Step 2 | Go to Step 4 |
With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | System OK |