The PCM/ECM monitors engine speed deviation from the target idle engine speed when the vehicle is stopped and the throttle valve opening is stable. The PCM/ECM sets DTC P0506 if the difference to the target idle engine speed is lower than the predetermined threshold.
| Item | Detecting Condition | Possible Cause | 
| DTC Strategy | 
										•
									 Monitoring deviation between target idle speed and actual engine speed | 1. Restriction in intake or exhaust system 2. Contact resistance in connectors 3. Faulty ETC | 
| Enable Conditions | 
										•
									 Coolant temp. > 165℉ 
										•
									 Time elapsed after ( pedal value = 0% and vehicle speed = 0mph) 
										•
									 11< Battery voltage <16 
										•
									 No relevant failure | |
| Threshold Value | 
										•
									 Current RPM < Target RPM -100rpm Engine speed too Low | |
| Diagnostic Time | 
										•
									 17 sec. | |
| Mil On Condition | 
										•
									 2 driving cycle |