Circuit Description
The idle speed is controlled by the engine control module (ECM). The ECM will command the throttle valve motor to open or close the throttle valve in order to maintain the desired idle speed.
Conditions for Running the DTC
| • | DTCs P0110, P0115, P0116, P0411, P0440, P0442, P0443, P0446, P0455, P0500, P1120, or P1220 are not set. |
| • | The intake air temperature (IAT) is more than 0°C (32°F). |
| • | The engine coolant temperature (ECT) is more than 80°C (176°F). |
| • | The engine load is less than 2 percent. |
| • | The evaporative emissions (EVAP) diagnostic is not running. |
| • | The EVAP is not purging. |
| • | The vehicle speed is 0 km/h (0 mph). |
| • | The secondary air injection (AIR) diagnostic is not running. |
Conditions for Setting P0506
The actual engine RPM is lower than the desired idle speed by at least 100 RPM.
Conditions for Setting P0507
The actual engine RPM is more than the desired idle speed by at least 200 RPM.
OR
The fuel cut-off occurs more than 3 times when the diagnostic is performed.
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 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
For an intermittent, refer to Symptoms - Engine Controls .
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.
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This test determines whether the engine can achieve the commanded RPM, and if not, whether the RPM is too high or too low.
Step | Action | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||||||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |||||||
Are any throttle actuator control (TAC), throttle position (TP), or accelerator pedal position (APP) DTCs set? | Go to Step 3 | ||||||||
Does the engine speed correspond within 100 RPM, with each command? | Go to Diagnostic Aids | Go to Step 4 | |||||||
4 | Is the engine RPM more than 100 RPM above the desired RPM? | Go to Step 5 | Go to Step 6 | ||||||
5 | Check for the following conditions:
Did you find and correct the condition? | Go to Step 7 | -- | ||||||
6 | Check for the following conditions:
Did you find and correct the condition? | Go to Step 7 | -- | ||||||
7 |
Does the DTC run and pass? | Go to Step 8 | Go to Step 2 | ||||||
8 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | System OK | |||||||
