Why is my Chevy Volt check engine light on?
A Chevy Volt's check engine light indicates the onboard computer has detected a fault; it can be something simple like a loose gas cap or a more complex issue with the gasoline engine, emissions system, or the high‑voltage hybrid components. The fastest way to know what's wrong is to read the diagnostic trouble codes (DTCs) with an OBD‑II scanner or at a Chevy service center.
What the light means on a Volt
The Volt is a plug‑in hybrid that uses a gasoline engine to generate electricity and an electric drive to move the car. The check engine light is triggered whenever a fault is logged in either the internal combustion engine management system, the emissions control system, or the hybrid/high‑voltage subsystem that GM uses to manage battery charging and inverter operations. In many cases the issue is minor, but some faults can affect performance or emissions and should be diagnosed promptly.
How OBD codes map to Volt systems
Like other vehicles, Volt codes begin with P (powertrain), B (body), C (chassis), or U (network). For a Volt, common P‑codes relate to engine misfires, oxygen sensors, evaporative emission system leaks, catalytic converter efficiency, and hybrid‑drive components such as the inverter or battery sensors. A professional scan is the reliable way to identify the exact part and required repair.
Common causes of a Volt check engine light
Below are the typical categories of faults that trigger the light on a Chevy Volt. The list is not exhaustive, but it covers the issues you’re most likely to encounter.
- Loose or faulty gas cap, which can trigger evap leak codes (often P0455 or P0456).
- Emissions system faults, including oxygen sensors, catalytic converter efficiency, or EVAP purge valve leaks.
- Mass airflow sensor or intake issues that disturb the air‑fuel mixture.
- Ignition and fuel delivery problems that can cause misfires (spark plugs, ignition coils) and related codes.
- High‑voltage battery pack or charging system problems (battery temperature, BMS faults, inverter issues) that affect hybrid operation.
- Cooling system or thermostat sensor faults that affect engine temperature management.
- Hybrid transmission control or software glitches that trigger powertrain codes.
- Electrical wiring and sensor faults within engine bay or underhood harnesses.
Most of these are routine to diagnose and repair, but some indicate more significant issues that should be inspected promptly to avoid reduced efficiency or potential damage.
How to diagnose and what to do now
If you see the light, follow a careful diagnostic approach to determine severity and urgency. Start with basic checks and then move to code reading and professional service as needed.
- Check for a loose or damaged gas cap and reseat or replace it if needed; then clear codes and see if the light returns.
- Observe driving behavior and symptoms: rough running, reduced power, strange noises, misfiring, or abnormal battery range changes.
- Scan for diagnostic trouble codes using an OBD‑II scanner or have a technician read the codes; note any freeze‑frame data and pending codes.
- Research the code(s) using a trusted source (service manual, dealer portal, or reputable automotive sites) to identify likely causes and recommended repairs.
- Check for GM service bulletins or recalls related to your VIN that might cover the issue; discuss with your dealer or shop.
- Decide on next steps: if codes point to a minor evap leak or sensor, you may be able to schedule a repair visit soon; if codes indicate misfire or high‑voltage/hybrid system faults, limit driving and seek immediate service.
Note: A flashing check engine light typically indicates a severe misfire or other critical fault that can cause damage if driven; in that case, pull over safely and arrange towing or roadside assistance.
Warranty and service considerations
The Chevy Volt’s high‑voltage battery and hybrid components are typically covered by GM’s warranty terms for a substantial period (commonly 8 years/100,000 miles in many regions). Emissions control components and the powertrain may have separate coverage. Always check your specific vehicle warranty booklet and confirm with your dealer, as coverage can vary by year, trim, and location. If your light is related to the battery or inverter, a dealership visit is usually required for diagnosis and potential replacement.
What to tell a mechanic
To help the mechanic diagnose quickly, provide the exact code(s), the approximate mileage, any symptoms you observed, whether the engine ran smoothly or there was misfiring, and whether you noticed anything unusual about battery charging and range. If you’ve recently filled up with fuel or popped the gas cap while fueling, mention that as well.
Summary
In short, a Chevy Volt check engine light signals a fault in either the engine, emissions, or hybrid systems. While many triggers are minor (like a loose gas cap), others can involve the high‑voltage battery or hybrid inverter. The right first step is to read the stored diagnostic trouble codes and have a qualified technician diagnose and repair the root cause. Addressing issues early can prevent more costly damage and ensure safe, efficient operation of your plug‑in hybrid.
If you’d like, I can tailor the guidance to your exact model year and the codes you’re seeing.
What are the most common problems with Chevy Volt?
Common Chevy Volt problems include battery degradation, issues with the gasoline engine due to carbon buildup from short run cycles, charging system malfunctions, and electrical system faults like failed control modules. Other reported issues involve brake problems like premature wear and noise, and various software glitches.
This video discusses potential issues to watch out for when buying a used Chevy Volt: 1mThe Disgruntled MechanicYouTube · Jul 18, 2020
Battery and charging
- Battery degradation: Over time, the high-voltage battery can lose capacity, which results in a shorter electric-only range.
- Charging problems: Owners have reported the car won't charge at home, won't fully charge, or doesn't work with certain public chargers. A failed condenser in the charging system can also be a problem.
- High-voltage cooling system issues: A problem with the cooling system can prevent the battery from charging.
Gasoline engine
- Carbon buildup: The direct-injection engine can develop carbon buildup on the valves due to frequent, short run cycles, leading to rough idle, misfires, and reduced performance.
- Stuck valves: Owners have reported a stuck valve in the engine, sometimes related to the oil pressure control solenoid.
Brakes
- Premature wear: Owners have noted that brake pads and rotors wear out sooner than expected.
- Noise and vibration: Common issues include brake noise or vibrations and pulsations in the brake pedal.
- System failure: In some cases, problems with the master cylinder, calipers, or anti-lock system have been reported.
- Regenerative braking issues: Some owners have experienced problems related to the regenerative braking system.
This video shows an example of a common problem with the Chevy Volt's shifter: 56sWatchJRGoYouTube · May 30, 2025
Electrical and software
- Control module failure: The Battery Energy Control Module (BECM) or Battery Control Module (BCM) can fail, causing significant reliability issues, including the car stopping unexpectedly.
- Software glitches: Various software glitches can occur, leading to problems like display screen flickering or intermittent satellite radio reception.
- Electric drive motor malfunction: At least one owner has reported a malfunction of the electric drive motor.
Why is my Chevy Volt engine light on?
A Chevy Volt's check engine light can be on for various reasons, ranging from simple issues like a loose gas cap to more complex problems with the engine, emissions, or hybrid system. The specific cause is identified by a stored diagnostic trouble code, which can be retrieved by using an on-board diagnostics (OBD-II) scanner. For a blinking light, pull over as soon as it is safe to do so, and for a solid light, schedule service soon.
This video explains the different reasons for a check engine light on a Chevy Volt, including issues with the high-voltage powertrain: 59sSeidelRanchYouTube · Jun 5, 2024
Common causes
- Loose gas cap: This is one of the simplest and most common reasons. A loose or faulty cap can cause an evaporative emissions system leak.
- Faulty oxygen sensor: This sensor helps regulate the fuel mixture. If it fails, it can lead to poor fuel economy and increased emissions.
- Bad spark plugs: Worn-out or fouled spark plugs can cause engine misfires.
- Issues with the catalytic converter: This part of the exhaust system is responsible for reducing harmful emissions. A failing one can trigger the light and negatively affect performance.
- Emissions system problems: Issues with the evaporative emission control (EVAP) system or other components can trigger the light.
- Mass Airflow (MAF) sensor failure: A dirty or faulty MAF sensor can affect the engine's air-fuel mixture.
- Hybrid system faults: On a Chevy Volt, a check engine light can also indicate a problem with the high-voltage battery or regenerative braking system, especially if the light is blinking.
This video demonstrates how to resolve an engine maintenance message on a Chevy Volt by running the engine: 1mTom LeemanYouTube · Mar 26, 2021
What to do
- Check the gas cap: Make sure it is tightened securely. If it's loose, tighten it and see if the light turns off after a short drive.
- Note the light's behavior:
- Blinking: This indicates a more severe issue. Pull over to a safe spot as soon as possible and turn off the engine.
- Solid: Drive normally but get it checked soon. However, if you notice any performance issues, take it in immediately.
- Get the trouble code read: To determine the exact cause, you need to have the vehicle's onboard computer scanned for fault codes.
- Many auto parts stores offer this service for free.
- You can also use a personal OBD-II scanner.
- A mechanic can also retrieve the codes for you.
- Avoid guessing: Don't start replacing parts based on assumptions. The fault code will provide the necessary information to guide the diagnosis.
- Service the vehicle: Once you have the code, you can use it to get the correct repair done.
What is the most common cause for a check engine light to come on?
The most common reasons for a check engine light are a loose or faulty gas cap, a failing oxygen sensor, or bad spark plugs. Other frequent causes include a malfunctioning catalytic converter, a dirty mass airflow sensor, or vacuum leaks.
Common causes
This video explains the top reasons for the check engine light: 47sThe Auto BrainYouTube · May 5, 2025
- Loose or damaged gas cap: A loose or cracked gas cap can allow fuel vapors to escape, triggering the light. This is often one of the easiest fixes.
- Failing oxygen sensor: The oxygen sensor measures the amount of oxygen in your exhaust. If it's failing, it can lead to a drop in fuel efficiency and turn on the light.
- Bad spark plugs or ignition coils: Worn-out spark plugs or a failing ignition coil can cause engine misfires, leading to poor performance and triggering the light.
- Faulty catalytic converter: This component converts harmful exhaust gases into less harmful ones. A failing catalytic converter can cause a significant drop in fuel efficiency and performance.
- Dirty or faulty mass airflow sensor (MAF): The MAF sensor measures the amount of air entering the engine. Contamination or a malfunction can cause the light to come on.
- Vacuum leaks: Cracks or leaks in vacuum hoses can disrupt the air-fuel mixture and trigger the light.
What to do
- First, check that your gas cap is on tightly and is not damaged.
- If the light remains on, you can use an OBD-II scanner to read the specific code from your car's computer to diagnose the problem more accurately.
- Some issues, like a loose gas cap or minor vacuum leaks, can be fixed yourself. Others, like a failing catalytic converter or oxygen sensor, may require a professional mechanic.
How to clear check engine light Chevy Volt?
To reset the check engine light on a Chevy Volt, first resolve the underlying issue, as the light will often turn off on its own after a few drive cycles. If the light persists after fixing the problem, you can manually reset it by using an OBD-II scanner to clear the codes, or by disconnecting the negative terminal of the 12-volt battery for about 10-15 minutes to clear the car's computer memory.
This video demonstrates how to reset the check engine light on a Chevy Volt using a diagnostic tool: 49sHidalgo Motors Co TVYouTube · Dec 28, 2023
Method 1: Using an OBD-II scanner
- Plug the scanner: into the OBD-II port, usually located under the dashboard.
- Turn the ignition: to the "on" or "accessory" position, without starting the engine.
- Use the scanner: to read the fault codes and then select the option to "clear" or "erase" the codes.
- Turn the vehicle off and back on: to see if the light has gone out.
Method 2: Disconnecting the battery
- Turn off the vehicle: and open the hood.
- Locate the negative terminal: on the 12-volt battery, which is typically black and marked with a minus (-) sign.
- Loosen the bolt: on the negative terminal with a wrench and disconnect the negative cable.
- Wait 10 to 15 minutes: for the vehicle's computer to fully power down.
- Reconnect the negative cable: and tighten the bolt securely.
- Start the vehicle: to see if the check engine light has been reset.
This video shows how to reset the check engine light on a Chevy Volt by disconnecting the battery: 58sMechanic BaseYouTube · May 24, 2023
Important considerations
- Fix the problem first: Both of these methods will only temporarily turn off the light. If the underlying issue isn't resolved, the check engine light will likely come back on.
- Drive cycles: After fixing a simple problem like a loose gas cap, the light may automatically reset itself after several miles of driving as the car's computer re-evaluates the system.
- Diagnostic services: If the light returns or you are unsure of the cause, it is best to have a qualified mechanic diagnose and fix the problem to prevent potential damage to your vehicle.
You can also watch this video to learn about the potential cause of the check engine light on a Chevy Volt: 55sAuto Scholar with Mr BYouTube · Aug 1, 2023
