Circuit Description
The throttle actuator control (TAC) motor is a DC motor that is part of the throttle body assembly. The TAC motor drives the throttle valve. The engine control module (ECM) controls the TAC motor based on throttle position (TP) sensor input. The idle speed is controlled by the ECM based on various inputs. The ECM commands the throttle actuator control motor to open or close the throttle valve in order to maintain the desired idle speed. If the ECM detects the actual idle speed and the desired idle speed are not within a predetermined amount, this DTC sets.
DTC Descriptors
This diagnostic procedure supports the following DTCs.
| • | DTC P0506 Idle Speed Low |
| • | DTC P0507 Idle Speed High |
Conditions for Running the DTC
| • | Before the ECM can report DTC P0506 or P0507 failed, transmission DTCs P0722 and P0723 must run and pass. |
| • | DTCs P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0221, P0222, P0223, P0442, P0443, P0446, P0455, P0458, P0459, P0496, P0722, and P0723 are not set. |
| • | The engine coolant temperature (ECT) is more than 60°C (140°F). |
| • | The intake air temperature (IAT) is more than -10.5°C (+13°F). |
| • | The volumetric efficiency is less than 35 percent, DTC P0506 only. |
| • | The evaporative emission (EVAP) canister purge valve is OFF. |
| • | A vehicle speed was detected prior to the diagnostic running. |
| • | The vehicle speed is 0 km/h (0 mph). |
| • | DTC P0506 and P0507 run continuously once the above conditions are met. |
Conditions for Setting DTC P0506
The actual engine speed is less than the desired idle speed by at least 100 RPM for 10 seconds.
Conditions for Setting DTC P0507
The actual engine speed is more than the desired idle speed by at least 200 RPM for 10 seconds.
Or
The ECM detects 3 fuel cut-offs due to an engine over speed condition while the engine is idling.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 4 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
| • | Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector. |
| • | The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to Engine Controls Component Views . |
| • | For an intermittent condition, refer to Intermittent Conditions . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
If any of the listed DTCs are present, correct the condition before returning to this table.
-
This test determines whether the engine can achieve the commanded RPM, and if not, whether the engine speed is too high or too low.
Step | Action | Values | Yes | No | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | ||||||||||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |||||||||||||
Are any throttle actuator control (TAC), throttle position (TP) sensor, or accelerator pedal position (APP) sensor DTCs set? | -- | Go to Step 3 | ||||||||||||||
Is the actual engine speed within the specified value of the commanded engine speed, with each command? | 100 RPM | Go to Step 4 | Go to Step 5 | |||||||||||||
4 |
Did the DTC fail this ignition? | -- | Go to Step 5 | Go to Intermittent Conditions | ||||||||||||
5 | Is the engine speed more than the specified value above the desired RPM? | 100 RPM | Go to Step 6 | Go to Step 7 | ||||||||||||
6 |
Did you complete the repair? | -- | Go to Step 8 | -- | ||||||||||||
7 |
Did you complete the repair? | -- | Go to Step 8 | -- | ||||||||||||
8 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 9 | ||||||||||||
9 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||||||||
