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Home >> Jeep >> 2021 >> Gladiator Mojave, Part Time T/Case Control, Automatic Trans >> Repair and Diagnosis >> Engine Performance >> System >> DRIVEABILITY - Gas - Non-DTC Based Diagnostics >> Diagnosis And Testing >> Checking The Ignition Coil Operation >> Diagnostic Test

Diagnostic Test

  1. IGNITION COIL WIRING OR CONNECTORS 
    NOTE:

    Diagnose and repair any ignition coil, Camshaft Position (CMP) Sensor, or Crankshaft Position (CKP) Sensor DTCs before proceeding with this test.

    1. Turn the ignition off.
    2. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Ignition Coil for the cylinder being tested and the PCM.
    3. Look for any chafed, pierced, pinched, or partially broken wires.
    4. Look for broken, bent, pushed out or corroded terminals.
      NOTE:

      If the vehicle is not equipped with the coil on plug ignition system, check the resistance of the ignition wire(s) before checking the cylinder with a spark tester. The resistance should be below 10k ohms.

      Were any problems found?

      Yes 

      • Repair as necessary in accordance with the Service Information.
      • Perform the Powertrain Verification Test. Refer to the appropriate service information .

      No 

      • Go To  2
  2. VERIFY ENGINE SPEED INPUT FROM THE CKP SENSOR 
    1. Turn the ignition on.
    2. With a scan tool, navigate to Data Display and monitor the engine speed.
    3. Crank the engine for up to 10.0 seconds.

      Was there any engine speed input detected on the scan tool during cranking?

      Yes 

      • Go To  3

      No 

      • Verify that the CKP Sensor is properly mounted. Replace the CKP Sensor if no mounting issues are found.
      • Perform the Powertrain Verification Test. Refer to the appropriate service information .
  3. IGNITION COIL OPERATION 
    NOTE:

    Inspect the ignition coil for damage, carbon tracking on the coil or a damaged spark plug insulator boot. If a problem is found, replace the ignition coil.

    NOTE:

    Some coils must have a spark tester installed on both sides of the coil during the following test. During the test, each side of the coil should output a crisp blue spark that is able to jump the gap of the spark tester.

    NOTE:

    On some engines, it may be necessary to remove the upper intake manifold to access the ignition coils. Once the ignition coil has been removed, the intake must be installed in order to crank the engine. Move the ignition coil harness connector through the slots in the upper intake and then connect the coil to the harness connector. Secure the upper intake to the lower intake in accordance with the Service Information.

    1. Turn the ignition off.
    2. If the vehicle is equipped with coil on plug ignition system, remove the ignition coil for the cylinder being tested.
    3. Disconnect the fuel injector harness connector for the cylinder being tested.
    4. For coil on plug ignition systems, install a spark tester(s) on the ignition coil, otherwise install the spark tester to the ignition wire.
    5. While cranking the engine observe the spark coming from the spark tester.
      NOTE:

      A crisp blue spark that jumps the gap of the spark tester should be generated.

      Is good spark present?

      Yes 

      • Go To  8

      No 

      • Go To  4
  4. CHECK THE ASD RELAY OUTPUT CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Disconnect the Ignition Coil harness connector.
    3. Turn the ignition on.
    4. With the scan tool, actuate the ASD Relay to on.
    5. Using a 12 volt test light connected to ground, check the ASD Relay output circuit at the ignition coil harness connector.
      NOTE:

      The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.

      Is the test light illuminated and bright during the actuation?

      Yes 

      • Go To  5

      No 

      • Repair the ASD Relay output circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  5. IGNITION COIL 
    WARNING:

    When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in possible serious or fatal injury.

    1. Using a 12 volt test light connected to 12 volts, check the Ignition Coil Control circuit for the cylinder being tested in the Ignition Coil harness connector.
    2. Crank the engine for five seconds.
      NOTE:

      The test light should blink each time the circuit is activated by the PCM.

      Does the test light blink each time the circuit is activated by the PCM?

      Yes 

      • Replace the Ignition Coil in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  6
  6. CHECK THE IGNITION COIL CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the Ignition Coil control circuit for the cylinder being tested between the Ignition Coil harness connector and the PCM harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  7

      No 

      • Repair the Ignition Coil Control circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  7. POWERTRAIN CONTROL MODULE (PCM) 
    1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Ignition Coil for the cylinder being tested and the PCM.
    2. Look for any chafed, pierced, pinched, or partially broken wires.
    3. Look for broken, bent, pushed out or corroded terminals.
    4. Perform any Service Bulletins that may apply.

      Were any problems found?

      Yes 

      No 

  8. SPARK PLUG(S) 
    1. Turn the ignition off.
    2. Remove the spark plug.
    3. Inspect the spark plug for any of the following conditions:
      • Cracks or damage
      • Carbon tracking
      • Foreign material
      • Gap not within specification
      • Loose or broken electrode
      • Fuel fouled
      NOTE:

      Lightly tap the bottom of the spark plug on a solid surface. The electrode in the spark plug should not move.

      Were any problems found?

      Yes 

      No 

      • Test Complete.
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