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Home › Chevrolet › 2005 › Optra5 Base, Standard › Repair and Diagnosis › Engine Performance › System › Engine Controls - 1.8L (L79) - DTC P0301 To DTC P1114 › DTC P0301-P0304 › Test Description

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. 5:  This step tests the condition of the spark plug wire. You may also swap the suspected spark plug wire with a wire from a cylinder that is operating correctly, to verify whether a condition exists.
Step Action Values Yes No
1 Did you perform the Diagnostic System Check - Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2 Were you sent here from DTC P0300? - Go to Step 3  Go to DTC P0300
3
  1. Turn OFF the ignition.
  2. Disconnect the appropriate spark plug wire from the spark plug.
  3. Connect the J 26792  Spark Tester to the spark plug wire and a good ground.
  4. Crank or start the engine.
IMPORTANT: If the spark tester sparks once or twice and then quits, this is considered no spark.
Does the J 26792  spark and is the spark consistent?		 - Go to Step 4  Go to Step 5 
4
  1. Turn OFF the ignition.
  2. Remove the spark plug from the cylinder that indicated a misfire.
  3. Inspect the spark plug. Refer to Spark Plug Inspection .
Does the spark plug appear to be OK?		 - Go to Step 9  Go to Step 6 
5 
  1. Remove the spark plug wire for the affected cylinder. Refer to Spark Plug Wire Replacement .
  2. Inspect the spark plug wire. Refer to Spark Plug Wire Inspection .
  3. Measure the resistance of the spark plug wire with a DMM.
Is the spark plug wire resistance less than the specified value, but more than zero?		 1,000 Ω per 30 cm (per ft) Go to Electronic Ignition (EI) System Diagnosis Go to Step 12 
6 Is the spark plug oil or coolant fouled? - Go to Symptoms - Engine Mechanical in Engine Mechanical - 1.8L (L79) Go to Step 7 
7 Is the spark plug gas fouled? - Go to Step 10  Go to Step 8 
8 Does the spark plug show any signs of being cracked, worn, or incorrectly gapped? - Go to Step 11  Go to Step 9 
9
  1. Swap the suspected spark plug with another cylinder that is operating correctly.
  2. Operate the engine within the conditions that the misfire occurred.
  3. Observe the Misfire Current Cylinder parameters with a scan tool.
Did the misfire move with the spark plug?		 - Go to Step 11  Go to Step 10 
10
IMPORTANT:
  • Make sure all the fuel injectors operate. High resistance in a fuel injector circuit causes the fuel injector to be inoperative without setting a fuel injector DTC.
  • Return to this diagnostic after you complete the Fuel Injector Coil Test.
Perform the fuel injector coil test. Refer to Fuel Injector Coil Test .Did you find and correct the condition?		 - Go to Step 13  Go to Symptoms - Engine Mechanical in Engine Mechanical - 1.8L (L79)
11 Replace the spark plug. Refer to Spark Plug Replacement
Did you complete the replacement?		 - Go to Step 13  -
12
IMPORTANT: An open or failed spark plug wire could cause damage to the ignition coil. Verify that the ignition coil can fire the J 26792  for the affected cylinder after the spark plug wire is replaced.
Replace the spark plug wire. Refer to Spark Plug Wire ReplacementDid you complete the replacement?		 - Go to Step 13  -
13
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. 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 14 
14 Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List System OK
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