How to Test your Fuel Injectors using a YOUCANIC Scanner
Is your engine running rough? Has your gas mileage dropped? If replacing your mass airflow sensor didn’t fix the issue, your car might have a faulty fuel injector! Before you start blindly swapping parts, figure out which injector is faulty using a YOUCANIC scanner!
Demo model: Mercedes-Benz
Step-by-step guide
These steps will not work on all cars. Cars made before the year 2000 might not have active test capabilities, so you will not be able to follow these steps to determine which fuel injector is faulty.
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The steps below mainly apply to Mercedes vehicles. The YOUCANIC scanner is able to perform this function on many different makes and models, but the exact steps and pathway may vary, as different manufacturers have different naming systems.
- Connect your VCI adapter to your OBD-II port.
- Select Diagnostic on the home screen of your scanner.
- On the following screen, find and select your vehicle make, then select the SmartVIN option.
- Select Diagnosis, then Control Modules on the following screens. Next, select Drive.
- Select Active Test, and scroll until you see a Fuel Injectors option.NOTE: The location and name of this active test will vary by vehicle. Different makes will have different names for various systems.
- Follow the on-screen prompts. For this particular active test, your scanner will have you turn your engine on. RPMs should not exceed 1000.
- The following screen allows you to turn different injectors on and off to determine which one is faulty.
- To turn off an injector, select the cylinder number on the bottom of the screen. If your car starts running rough and you notice a change in RPMs, the injector is working. If you turn off a cylinder and you don’t notice a change in engine performance, that fuel injector might be faulty.
- To turn injectors back on, scroll to the bottom of the screen and select the Switch on all cylinders option. In the demo video above, the number 7 was selected because this Mercedes-Benz only has six fuel injectors.
- For further troubleshooting, check live data values. Exit the Active Tests page, and select Live Data.
- Next, select Test values while idling, and press Select All.
- Under Live Data, you can observe different values and compare them to the range they should fall within.
NOTE: The location and name of this active test will vary by vehicle. Different makes will have different names for various systems.
If your Fuel Injectors are Good
After running active tests to check for a faulty injector didn’t help narrow down the issue, check your mass airflow sensor or spark plugs. Spark plugs should be replaced every 30,000 to 90,000 miles, so if your car is experiencing misfires and you haven’t replaced them in a while, that could also be the problem. Not sure how? Visit YOUCANIC’s YouTube channel! There are plenty of how-to and DIY guides, including videos on spark plug replacement.
Disclaimer: This guide may not apply to all vehicle makes and models. If you need to verify coverage for your particular vehicle, please contact YOUCANIC support or use our Compatibility Checker.
