Description
The throttle valve in the throttle body utilizes a throttle return spring to assist in positioning the throttle valve at a resting or default position. The powertrain control module (PCM) uses driver input from the accelerator pedal position (APP) sensor in order to calculate the desired throttle position. The PCM sends the desired throttle position or target value to the throttle actuator control (TAC) module. The TAC module achieves the desired throttle position by commanding the throttle control motor to position the throttle valve at the target value. The TAC module then compares the throttle position (TP) sensor 1 value to the target value. If necessary, the throttle control motor is moved slightly in order to obtain the exact target value position.
The PCM is supplied with ignition positive voltage through the ETCS fuse for the operation of the TAC motor. If the PCM does not receive this positive voltage, a DTC P2118 sets. For additional information on the operation of the TAC system, refer to Throttle Actuator Control (TAC) System Description .
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P2118 Throttle Actuator Control Motor Current Performance
Conditions for Running the DTC
| • | Battery voltage is more than 8 volts. |
| • | DTC P2118 runs continuously once the above condition has been met. |
Conditions for Setting the DTC
The voltage of the power supply to the TAC motor is less than 4 volts for 1 second.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL). |
| • | The PCM stores the conditions that were present when the DTC set as Freeze Frame data. |
| • | The engine will operate in the reduced power mode and the TP sensor angle will default to 19 percent. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL on the third consecutive trip in which the diagnostic runs without a fault. |
| • | The PCM clears a History DTC after 40 consecutive warm-up cycles without a fault. |
| • | You use the scan tool Clear DTC Information function. |
Diagnostic Aids
| • | TAC Motor Current is displayed on the scan tool, but the displayed value freezes when the MIL illuminates and the DTC sets. |
| • | DTC P2118 sets when there is an open or a short to ground in the TAC Ignition positive voltage circuit. When this fault occurs, a sudden surge of current can be detected in the TAC motor control circuits, causing a DTC P2103 to also set. |
| • | For an intermittent condition, refer to Intermittent Conditions . |
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 Reference: 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 | |
Did the DTC fail this ignition? | Go to Step 4 | Go to Step 3 | |
3 |
Did the DTC fail this ignition cycle? | Go to Step 4 | Go to Diagnostic Aids |
4 | Inspect the ETCS fuse for an open. Was the ETCS fuse open? | Go to Step 8 | Go to Step 5 |
5 |
Did you find and repair a condition? | Go to Step 9 | Go to Step 6 |
6 |
Did you find and repair a condition? | Go to Step 9 | Go to Step 7 |
7 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 9 | -- |
8 | Replace the ETCS fuse and repair the short to ground in the TAC ignition positive volage circuit. Refer to Wiring Repairs . Did you complete the repair? | Go to Step 9 | -- |
9 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 10 |
10 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | System OK | |
