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Home >> Cadillac >> 2017 >> Escalade ESV Base, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 14 (Engine Controls And Fuel - 6.0L (L96) - DTC P0351 To DTC P2636 And Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> Fuel Injector Diagnosis >> Circuit/System Verification

Circuit/System Verification

WARNING: This page is about a different car, the 2017 Chevrolet Suburban 3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
  • The resistance test must be performed at the fuel injector or mis-diagnosis will occur.
  • The DMM and test leads must be calibrated to 0 Ω in order to prevent mis-diagnosis.

Verify the resistance of each fuel injector:

Fuel Injector Coil Test

  1. Ignition ON, verify the scan tool ECT temperature is between 10 - 32°C (50 - 90°F).
    • If not between 10 - 32°C (50 - 90°F) 
    1. Measure and record the resistance of each Q17 Fuel Injector with a DMM.
    2. Subtract the lowest resistance value from the highest resistance value.
    3. Verify the difference between the lowest value and the highest value is 3 Ω or less.
      • If the difference is greater than 3 Ω
      1. Add all of the Q17 Fuel Injector resistance values to obtain a total resistance value.
      2. Divide the total resistance by the number of fuel injectors to obtain an average resistance value.
      3. Subtract the lowest individual fuel injector resistance value from the average resistance value
      4. Subtract the average resistance value from the highest individual fuel injector resistance value.
      5. Replace the Q17 Fuel Injector that displays the greatest difference above or below the average value.
    • If between 10 - 32°C (50 - 90°F) 
  2. Test for 11 - 14 Ω between terminal A and terminal B of each Q17 Fuel Injector.
    • If not between 11 - 14 Ω 

      Replace the Q17 Fuel Injector.

    • If between 11 - 14 Ω 
  3. Verify infinite resistance between each terminal at the Q17 Fuel Injector and the fuel injector housing/case.
    • If less than infinite resistance 

      Replace the Q17 Fuel Injector

    • If infinite resistance 
  4. Perform the Fuel Injector Balance Test - Fuel Pressure Test.

Fuel Injector Balance Test - Fuel Pressure Test

    NOTE:
    • DO NOT perform this test if the engine coolant temperature (ECT) is above 94°C (201°F). Irregular fuel pressure readings may result due to hot soak fuel boiling.
    • Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic.
    • Before proceeding with this test review the User Manual CH 48027-5 for Safety Information and Instructions.
  1. Install a CH-48027  pressure gauge. Refer to Fuel Pressure Gauge Installation and Removal .
  2. Ignition ON, engine OFF.
    3. NOTE:
    • The fuel pump relay may need to be commanded ON a few times in order to obtain the highest possible fuel pressure.
    • DO NOT start the engine.
  3. Command the Fuel Pump Enable ON with a scan tool.
  4. Verify the fuel pressure is 345 - 414 kPa (50 - 60 psi) with the fuel pump commanded ON.
    • If within 345 - 414 kPa (50 - 60 psi) 
  5. Verify the fuel pressure does not decrease greater than 34 kPa (5 psi) within 1 minute.
    • If the fuel pressure does not decreases greater than 34 kPa (5 psi) 
  6. Perform the appropriate Fuel Injector Balance Test.
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