Test Description

The number below refers to the step number on the diagnostic table.

2: If the actual CKP variation values are not within the learned values, the misfire counters may increment.

DTC P0300

Step	Action	Values	Yes	No
1	Did you perform the Diagnostic System Check - Vehicle?	-	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	IMPORTANT: You must perform the crankshaft position (CKP) system variation learn procedure before proceeding with this diagnostic table. Refer to CKP System Variation Learn Procedure . Start the engine. Allow the engine to idle or operate within the conditions listed in the Freeze Frame/Failure Records. Monitor all of the Misfire counters with the scan tool. Are any of the Misfire counters incrementing?	-	Go to Step 3	Go to Diagnostic Aids
3	Are any other DTCs set?	-	Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information	Go to Step 4
4	Can any abnormal engine noise be heard?	-	Go to Symptoms - Engine Mechanical in Engine Mechanical	Go to Step 5
5	Inspect the following components: The vacuum hoses and seals for splits, restrictions, and improper connections The throttle body and intake manifold for vacuum leaks The exhaust gas recirculation (EGR) system components for vacuum leaks or excessive flow The crankcase ventilation system for vacuum leaks-Refer to Crankcase Ventilation System Inspection/Diagnosis in Engine Mechanical. The engine control module (ECM) grounds for corrosion and loose connections-Refer to Ground Distribution Schematics in Wiring Systems. The exhaust system for restrictions-Refer to Restricted Exhaust in Engine Exhaust. The fuel for contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) . Did you find and correct the condition?	-	Go to Step 16	Go to Step 6
6	Turn OFF the ignition. Remove the fuel fuse. Remove the ignition coil assembly from the affected bank cylinder. Do not disconnect any electrical connectors from the ignition coil assembly. Refer to Ignition Coil(s) Replacement - Bank 1 or Ignition Coil(s) Replacement - Bank 2 . Install the J 36012-A Ignition Diagnostic Harness. See Special Tools . Install the J 26792 Spark Tester on one of the spark plug jumper wires of the affected cylinders. See Special Tools . Crank the engine with the remaining spark plug jumper wires connected. Did the spark tester spark on all cylinders?	-	Go to Step 7	Go to Electronic Ignition (EI) System Diagnosis
7	Remove the spark plugs from the cylinders that indicated a misfire. Inspect the spark plug. Refer to Spark Plug Inspection . Does the spark plug appear to be OK?	-	Go to Step 8	Go to Step 9
8	Exchange the suspected spark plug with another cylinder that is operating properly. Refer to Spark Plug Replacement . Operate the vehicle under the same conditions that the misfire occurred. Did the misfire move with the spark plug?	-	Go to Step 15	Go to Step 12
9	Are the spark plugs oil or coolant fouled?	-	Go to Symptoms - Engine Mechanical in Engine Mechanical	Go to Step 10
10	Are the spark plugs gas fouled?	-	Go to Step 13	Go to Step 11
11	Do the spark plugs show any signs of being cracked, worn, or improperly gapped?	-	Go to Step 14	Go to Step 12
12	Perform the fuel injector coil test. Refer to Fuel Injector Coil Test . Did you find and correct the condition?	-	Go to Step 16	Go to Symptoms - Engine Mechanical in Engine Mechanical
13	Perform the fuel system diagnosis. Refer to Fuel System Diagnosis . Did you find and correct the condition?	-	Go to Step 16	Go to Symptoms - Engine Mechanical in Engine Mechanical
14	Replace or gap the spark plug. Refer to Spark Plug Replacement . Did you complete the action?	-	Go to Step 16	-
15	Replace the faulty spark plugs. Refer to Spark Plug Replacement . Did you complete the replacement?	-	Go to Step 16	-
16	Was the customer concern the malfunction indicator lamp (MIL) flashing?	-	Go to Step 17	Go to Step 18
17	Operate the vehicle at the specified value for 4 minutes. Operate the vehicle within the Conditions for Running the DTC P0420 or P0430 as specified in the supporting text. Refer to DTC P0420 or P0430 . Does the DTC run and pass?	2,500 RPM	Go to Step 18	Go to DTC P0420 or P0430
18	Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	-	Go to Step 2	Go to Step 19
19	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?	-	Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information	System OK