Volt air valve malfunction

I own a Chevrolet Volt as well. I had a similar issue with the check engine light and it turned out to be related to the air system. Have you inspected the throttle body for any signs of unusual wear or damage? A malfunctioning throttle body can sometimes trigger similar symptoms. It might also be beneficial to check the Mass Airflow (MAF) sensor, as a faulty sensor can also lead to the check engine light illuminating.

Thank you for the information. I have not yet examined the throttle body in detail, but I will include it in my inspection. Could you elaborate on the specific symptoms you experienced, and whether they were consistently present? Were there any noticeable idle problems accompanying the illuminated check engine light? Any additional insights would be greatly appreciated.

My Volt presented with sporadic idle fluctuations and the check engine light would appear intermittently. After a few weeks, it became constant. Given your description, it's advisable to have a qualified technician diagnose the issue thoroughly. I spent many hours troubleshooting without any result. So I would strongly suggest bringing your car to the workshop. It might be worth the money.

I appreciate the confirmation and advice. As you suggested, I consulted with a certified mechanic. The diagnosis confirmed a defective hose connection from the pump to the air valve, consistent with my initial suspicion. The repair cost amounted to 175€.