2014 Jeep Wrangler JK Factory Service Manual 28 - DTC-Based Diagnostics

P2308-IGNITION COIL 3 SECONDARY CIRCUIT - INSUFFICIENT IONIZATION

For a complete wiring diagram, refer to the Wiring Information.



Possible Causes

(F344) ASD RELAY OUTPUT CIRCUIT
(K18) COIL CONTROL NO.3 CIRCUIT OPEN
(K18) COIL CONTROL NO.3 CIRCUIT SHORTED TO GROUND
COIL ON PLUG
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).


1. ACTIVE DTC



NOTE: Diagnose any ASD related DTCs before continuing.
1. Start the engine.
2. With a scan tool, select View DTCs.

NOTE: It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.


Is the DTC Active at this time?

Yes


No


2. (F344) ASD RELAY OUTPUT CIRCUIT
1. Turn the ignition off.
2. Disconnect the Coil on Plug harness connector.
3. Ignition on, engine not running.
4. With a scan tool, actuate the ASD Relay.
5. Using a 12-Volt test light connected to ground, probe the (F344) ASD Relay Output circuit in the Coil on Plug harness connector.


Does the test light illuminate brightly?

Yes


No


3. 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 may result in possible serious or fatal injury.

1. Using a 12-Volt test light connected to a 12 Volt source, probe the (K18) Coil Control No.3 circuit.
2. Crank the engine for 5.0 seconds while observing the test light.


What is the condition of the test light while cranking the engine?

Brightly blinking.


ON constantly.


OFF constantly.


4. SPARK PLUG

1. Turn the ignition off.
2. Remove the Spark Plug(s) in accordance with the Service Information.
3. Inspect the Spark Plug(s) for the following conditions:

  • Cracks
  • Carbon Tracking
  • Foreign Material
  • Gap size out of specifications
  • Loose or broken electrode


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


Were any of the above conditions present?

Yes


No


5. (K18) COIL CONTROL NO.3 CIRCUIT SHORTED TO GROUND
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Measure the resistance between ground and the (K18) Coil Control No.3 circuit in the Coil on Plug harness connector.


Is the resistance below 100 Ohms?

Yes


No


6. (K18) COIL CONTROL NO.3 CIRCUIT OPEN
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Measure the resistance of the (K18) Coil Control No.3 circuit from the Coil on Plug harness connector to the PCM C2 harness connector.


Is the resistance below 5.0 Ohms?

Yes


No


7. POWERTRAIN CONTROL MODULE (PCM)

1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Ignition Coil and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Ignition Coil and the Powertrain Control Module connectors.
4. Perform any Technical Service Bulletins that may apply.


Were there any problems found?

Yes


No