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.
• | One or more of the following DTCs are not set: P0110, P0115, P0116, P0411, P0440, P0442, P0443, P0446, P0455, P0500, P1120, P1220. |
• | 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 emission (EVAP) diagnostic is not running. |
• | The EVAP is not purging. |
• | The vehicle speed is 0 km/h (0 mph). |
• | Secondary air diagnostic is not running. |
The actual engine RPM is more than the desired idle speed by at least 200 RPM.
OR
The fuel cutoff occurs more than 3 times when the diagnostic is performed.
The ECM illuminates the malfunction indicator lamp (MIL) and records the operating conditions in the Freeze Frame on the second consecutive drive trip that the diagnostic runs and fails.
• | The ECM turns OFF the MIL after three consecutive drive trips that the diagnostic runs and passes. |
• | A History DTC clears after forty consecutive warm-up cycles in which no failures are reported by this diagnostic or any other emission related diagnostic. |
• | The scan tool clears the MIL/DTC. |
For an intermittent, refer to Symptoms . If the idle is high inspect the o-rings at the throttle body and upper intake plenum. Inspect the crankcase vent tube adapters o-ring that seals the adapter to the upper intake plenum.
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 or not the engine can achieve the commanded RPM, and if not, whether the RPM is too high or too low.
Step | Action | Values | Yes | No | ||||||
---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | |||||||
Are any TAC, TP, or APP DTCs set? | -- | Go to the applicable DTC table | 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 greater than 100 RPM above the desired RPM? | -- | Go to Step 5 | Go to Step 6 | ||||||
5 | Check for the following conditions:
Is the action complete? | -- | Go to Step 7 | -- | ||||||
6 | Check for the following conditions:
Is the action complete? | -- | Go to Step 7 | -- | ||||||
7 |
Does the scan tool indicate the diagnostic Passed? | Go to Step 8 | Go to Step 2 | |||||||
8 | Does the scan tool display any additional, undiagnosed DTCs? | -- | Go to the applicable DTC table | System OK |