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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1350 (Engine Control System (Troubleshooting & Diagnosis) -- 1.8L (LNK)) >> Troubleshooting >> Electronic Ignition (EI) System Diagnosis >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 2:  If there is a fault in either the crankshaft position (CKP) sensor or camshaft position (CMP) sensor circuits, the ignition system can malfunction. Repair the cause of a DTC P0335 or DTC P0340 first.
  2. 3:  If there is a fault in the electrical circuits between the PCM and the ignition coil assemblies, a DTC P0351-P0354 will set. Use the DTC P0351-P0354 diagnostic table in order to repair the ignition system failure.
  3. 7:  This step checks for a condition that can cause a loss of spark, even though the test in step 4 indicated that there was good spark.
  4. 10:  This step checks whether the engine will start and run. A repair that has been performed leading to this step may only have been a contributing cause of a no start condition. Returning to the Engine Cranks but Does Not Run diagnostic table will locate additional causes of the no start condition.
Electronic Ignition (EI) System Diagnosis

Step Action Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Powertrain Control Module (PCM) Connector End Views  or  Engine Controls Connector End Views 
1 Did you perform the Diagnostic System Check-Engine Controls? Go to Step 2  Go to Diagnostic System Check - Engine Controls
2  Check for DTCs with a scan tool.
Is a DTC P0335 or P0340 set?		 Go to DTC P0335 and DTC P0340 Go to Step 3 
3  Is DTC P0351, P0352, P0353, or P0354 set? Go to DTC P0351-P0354 Go to Step 4 
4
  1. Disconnect the electrical connector of each fuel injector.
  2. Disconnect the electrical connector at an ignition coil assembly.
  3. Remove the ignition coil assembly. Refer to Ignition Coil(s) Replacement . Do not remove the spark plugs.
  4. Connect a J 26792  Spark Tester or an equivalent to the spark plug boot of the ignition coil assembly.
  5. Clip the spark tester to ground.
  6. Connect the coil assembly electrical connector.
  7. Crank the engine and observe the spark tester.
  8. Repeat this test for each ignition coil assembly.
Is a crisp blue spark available at all ignition coil assemblies?		 Go to Step 7  Go to Step 5 
5 Is a crisp blue spark available at one or more ignition coil assemblies? Go to Step 6  Go to Step 9 
6
  1. Turn OFF the ignition.
  2. Replace the suspected faulty ignition coil with a known good ignition coil.
  3. Repeat the test for spark with the J 26792  described in step 4.
Was a crisp blue spark present while cranking the engine?		 Go to Step 8  Go to Step 9 
7  Inspect the ignition coil assembly boot and terminals for the following conditions:
  • Cracks
  • Corrosion
  • Carbon tracking

Did you find any of the listed conditions?		 Go to Step 8  Go to Step 10 
8 Replace the faulty ignition coil assembly or assemblies. Refer to Ignition Coil(s) Replacement .
Did you complete the replacement?		 Go to Step 10  -
9 Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .
Did you complete the replacement?		 Go to Step 10  -
10 
  1. Assemble the ignition system.
  2. Start the engine.
Does the engine start and run?		 Go to Step 11  Go to Engine Cranks but Does Not Run 
11 Check for DTCs.
Are any DTCs set?		 Go to Diagnostic Trouble Code (DTC) List System OK
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