Fuel Injector Coil Test

Verify the resistance of each fuel injector with one of the following methods:

• If the engine coolant temperature (ECT) sensor is between 10-32°C (50-90°F), the resistance of each fuel injector should be 11-14 ohms.
  • If the injectors measure OK, perform the AFIT Test Procedure.
  • If not within the specified range, replace the fuel injector.
• If the ECT sensor is not between 10-32°C (50-90°F), measure and record the resistance of each fuel injector with a DMM. Subtract the lowest resistance value from the highest resistance value. The difference between the lowest value and the highest value should be equal to or less than 3 ohms.
  • If the difference is equal to or less than 3 ohms, refer to AFIT Test Procedure.
  • If the difference is more than 3 ohms, add all of the fuel injector resistance values to obtain a total resistance value. Divide the total resistance value by the number of fuel injectors to obtain an average resistance value. Subtract the lowest individual fuel injector resistance value from the average resistance value. Compute the difference between the highest individual fuel injector resistance value and the average resistance value. Replace the fuel injector that displays the greatest difference above or below the average.

AFIT Test Procedure

IMPORTANT: DO NOT perform the AFIT Test Procedure if the ECT is above 60°C (150°F). High fuel pressure readings may result due to hot soak fuel boiling. With the engine OFF, the fuel pressure may increase to the setting of the pressure relief regulator valve, 550 kPa ± 5 percent (80 psi ± 5 percent).
IMPORTANT: Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic.
1. Turn OFF all accessories.
2. Turn OFF the ignition.
3. Install the AFIT. Refer to the AFIT User Guide.
4. Turn ON the AFIT and select the vehicle.
5. Turn ON the ignition and perform the Injector Test.
   • If the AFIT aborts testing due to fuel pressure or fuel leak down, refer to Fuel System Diagnosis .
6. View the test results.
   • If any injector exceeds the recommended tolerance, replace the injectors.