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How to check the electrical status of a Common Rail injector

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An electrical fault in a common rail injector can be one of the many reasons why the check engine light comes on in a car. A faulty CR injector would cause issues with the spray of fuel into the combustion chamber, or even stop it happening at all.

With this instructional video you can pick up a few tips on how to check the electrical status of a CR injector, courtesy of the experts at Delphi. Here you’ll find out:

• What equipment you’ll need
• How to measure resistance, inductance and insulation 
• How to replace a common rail injector
Diesel Fuel Systems How to Technicians 1 min read

What does the common rail injector do?

The common rail stores fuel that’s been pressurised inside the fuel pump, before the injector sprays it into the combustion chambers. With one injector per cylinder, each injector can be adjusted to the engine’s specification and optimum firing rate.

Why can common rail injectors fail?

Common rail injectors are pretty long-lasting in general, but wear and tear from issues such as deposit build-up and incorrect installation can affect them over time. There’s also the risk of water contamination from the fuel. Any of these can shorten a part’s lifespan. 

What does the electrical diagnostic tool do?

You can use the YDT720 electrical diagnostic tool to check the resistance, inductance and insulation of solenoid-type injectors. If these checks don’t return the desired results (depending on make and model), it’s possible that there’s an electrical problem with the injector.

What is the error code for a fuel injector?

If you’re checking for an issue with the fuel injector using an OBD tool, the error code will likely show up in the range beginning P0200. Other codes in this area tend to be related to engine misfire issues – which is one of the symptoms of a faulty common rail injector.

Why do I code the injector with a BlueTech tool?

If you’re fitting a replacement common rail injector, first make a note of the new correction code. Once it’s installed, reprogramme the ECU with the new correction code. You do this so that the engine knows it needs to adjust timings for the fuel spray.


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