The Check Engine Light (CEL) or Engine Management Light (EML) first started to appear in cars and vans in the 1980’s. The CEL is paired with the Engine Control Unit (ECU), the main onboard computer of most vehicles. The ECU monitors the engine for changes and issues, and if it finds one that cannot be remedied by tweaking the operation of parts itself, then it will trigger the CEL to illuminate. Alongside illuminating the check-engine light, the ECU will also send out trouble codes which are used to inform the mechanic what has happened. There are many reasons why the CEL can light up, so let’s narrow things down to those you’ll be most likely to experience.

Ill-fitting Gas Cap

Driver error is always the first place to start when faced with an illuminated CEL, as the problem can typically be easily remedied without the need for a mechanic. When refuelling your Sprinter, you should always pay full attention. This can be difficult during rush hour or if you’re running late, but taking a few seconds of extra time to make sure the gas cap is securely fitted can save you the trouble of an illuminated CEL. A loose-fitting gas cap allows fuel vapors to escape and impacts engine performance and fuel efficiency. If the gas cap is the issue, once it is resecured, the CEL should turn off within a day. However, if this does not happen, then you should bring your Sprinter to the professionals for diagnostic work.

Contaminated O2 Sensor

The O2 sensor, or oxygen sensor, is used by your Sprinter to monitor the amount of unburned oxygen that is present in the exhaust fumes. This is needed to make engine adjustments that balance the air-to-fuel ratio, making the engine perform better. Over time, the O2 sensor can get covered with ash. This prevents it from working correctly, which increases your emissions, reduces MPG, and triggers the CEL.

Catalytic Converter

This is a part problem you want to avoid if possible, as the catalytic converter is an expensive part to replace. The catalytic converter turns the toxic exhaust gases into cleaner emissions. Without this working correctly, you’ll probably notice a rotten egg (sulphurous) smell and you will also fail your emissions test and trigger the check engine light.

MAF Sensor

The Mass Airflow (MAF) sensor measures the amount of air entering your Sprinter’s engine, using the hot or cold wire method. It relays this information to other systems inside your engine, which allows for the precise amount of gas to be added to the combustion chamber for optimal running and ignition. The MAF sensor can become dirty or fail over time, leading to reduced performance, increased emissions, and engine stalling, which commonly triggers the CEL.

Spark Plugs/Wires

The spark plugs can trigger the CEL because when they become worn out or ineffective, they can lead to frequent ignition misfires. When the surface of the plugs becomes worn down, the gap between each set widens. The wider the gap becomes, the harder it is to successfully pass a spark between them, leading to misfire.

Aftermarket Alarm

When it isn’t installed correctly, the aftermarket alarm can trigger a range of problems to surface through the electrical system of your Sprinter. For example, it may drain the battery and cause the CEL to illuminate.

Vacuum Leak

Your Sprinter uses a vacuum system to reduce emissions, and help boost the brakes. When the CEL illuminates and your engine starts to surge when idle, a vacuum leak is the likely cause.

EGR Valve Failure

The EGR system is needed to reduce the levels of nitrogen oxide found within the exhaust fumes. When this becomes clogged or develops faults, the CEL will illuminate.

Flat Battery

The battery is needed to power your Sprinter’s electrical systems. If the charge is low, such as when the alternator fails, the CEL will illuminate to indicate a problem. The battery may either need to be charged or replaced.

Hayes European

If your Sprinter is dealing with unresolved Sprinter Engine Issue Check check engine light illumination, then don’t delay in speaking to our friendly team at Hayes European. We are perfectly located for drivers in Santa Cruz, Aptos, Soquel, and Capitola, CA communities. We’ll work hard to get to the bottom of the problem and will have you safely back on the road in no time.