How To Test a Toyota Corolla Fuel Injector

How To Test a Toyota Corolla Fuel Injector


Over time one or more of the Corolla Fuel Injector in your sedan can become clogged or even fail. When this happens your 1.6 liter Corolla will idle poorly and lose power as well as run inefficiently. Chances are if your Corolla Fuel Injector fails your Toyota will misfire and throw a check engine code for a cylinder specific issue.

Today I’ll be showing you how to test a Corolla Fuel Injector in a 1.6 liter equipped 1997 Toyota Corolla. In order to complete this guide you will need to use a digital multimeter. If you are not sure what a multimeter is, or even how to use one check out the tutorial here.

How To Test a Toyota Corolla Fuel Injector

Over time your Corolla fuel filter may become clogged or lose it’s ability to filter your fuel effectively. When this happens the chances of your fuel injector clogging increase. There’s a whole host of issues that can arise from a clogged Corolla Fuel Injector.

Symptoms of a failed Corolla Fuel Injector

Because one or more of your injectors won’t fire or spray the fuel properly, your engine will misfire and idle poorly. When this happens some of the following symptoms can occur.

  • Poor idle
  • Hard to start condition
  • Corolla won’t start
  • Engine Misfire
  • Check Engine Light ON

In order to test your Corolla Fuel Injector, you may need to use a OBDII scan tool. These tools will plug into your OBDII port and retrieve the check engine code that’s stored. If you are lucky the engine computer will store a specific trouble code, from the following below :

  • P0301: Cylinder #1 Misfire
  • P0302: Cylinder #2 Misfire
  • P0303: Cylinder #3 Misfire
  • P0304: Cylinder #4 Misfire

Testing the Internal Resistance of your Corolla Fuel Injector

There are several ways in which your Corolla Fuel Injector can fail. It can become clogged, fail internally or lose it’s ability to atomize fuel properly. Using this test you will be able to see if the internal coil inside your Toyota fuel injector has gone bad.

Turn your digital multimeter to the OHMS position, and carefully unplug the Toyota fuel injector you suspect has failed. Once you have your Corolla Fuel Injector unplugged you can probe both 1 and 2 terminals on the injector.

Toyota Corolla Fuel Injector

By measuring the resistance between terminals 1 and 2, you can determine whether or not the Corolla Fuel Injector has gone bad. If your fuel injector is still good, the 1.6 liter Toyota injector will read between 13.4 to 14.2 Ohms.

If your Corolla Fuel Injector returns this value but the cylinder is still having issues, it means your injector is clogged. You can take it to a fuel balancing service or have it sent out to be cleaned. However if the resistance is outside these values, it means the injector has gone bad. You will need to replace your Corolla Fuel Injector with a proper replacement injector, and use a OBDII scan tool to clear your stored DTC code.

Have any questions about our Corolla Fuel Injector tutorial? Leave us a comment below and let us know!