For 1990-2009 cars

### Circuit Description

Each engine cylinder has a dedicated ignition coil assembly. The ignition coil assembly contains the ignition module circuitry. The power distribution circuit supplies system voltage to each coil assembly when the ignition switch is in the ON or START positions. Each coil assembly regulates current flow through the primary coil windings, creating a magnetic field. The powertrain control module (PCM) signals each coil assembly to supply a spark in a cylinder through a trigger circuit. Each assembly does so by opening the primary circuit coil, inducing a high voltage in the secondary circuit coil. The high voltage in the secondary circuit grounds by arcing at the spark plug. This event creates a pulse on the fail safe circuit that the PCM recognizes as a confirmation of spark.

### Diagnostic Aids

Any circuit malfunction between the ignition coil assembly and the PCM should set a fail safe circuit DTC P1300, P1305, P1310, or P1315.

An ignition system that tests OK after sitting may have an ignition system that is susceptible to moisture. Spray water on the ignition system components and wiring in order to check for an intermittent failure.

### Test Description

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

1. 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. If there is a fault in the electrical circuits between the PCM and the ignition coil assemblies, a DTC P1300-P1315 will set. Use the DTC P1300-P1315 diagnostic table in order to repair the ignition system failure.

3. 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. 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.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Engine Controls Schematics
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 | Are DTCs P1300, P1305, P1310, or P1315 set? | Go to DTC P1300, P1305, P1310, P1315 | 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 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 Replacement . Did you complete the replacement? | Go to Step 10 | --
9 | Replace the PCM. Refer to Powertrain Control Module 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