Diagnostic Check Operation

The solenoid disables the EGR system periodically, to allow the PCM to perform a diagnostic check.

- During a diagnostic check, (activated only during select engine/driving conditions), the PCM tests the entire EGR system for failures.

- If the PCM detects an EGR system failure, the Malfunction Indicator Lamp (MIL), (previously called the Check Engine Lamp), in the instrument panel will be illuminated, indicating that immediate service is required.