Circuit Description
Ignition 1 voltage is supplied to the ignition coil. The engine control module (ECM) provides a ground for the ignition coil (IC) control circuits. When the ECM removes the ground path of the ignition primary coil, the magnetic field produced by the coil collapses. The collapsing magnetic field produces a voltage in the secondary coil which ignites the spark plugs. The sequencing and timing are controlled by the ECM. The ignition coil consists of the following circuits:
| • | The ignition 1 voltage |
| • | The IC 1 and 4 control |
| • | The IC 2 and 3 control |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests for an open in the ignition 1 voltage circuit.
-
This step test for high resistance in the ignition 1 voltage circuit.
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views | ||||||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | |||||
2 |
Important:
Attempt to start the engine. Does the engine start and run? | -- | Go to Step 3 | Go to Step 4 | ||||
3 | Does the engine misfire? | -- | Go to Step 6 | Go to Intermittent Conditions | ||||
Does the test lamp illuminate? | -- | Go to Step 5 | Go to Step 11 | |||||
Is the resistance less than the specified value? | 2 ohms | Go to Step 9 | Go to Step 11 | |||||
6 |
Important: An erratic or weak spark is considered a no spark condition. Important: The companion cylinders are 1/4 and 2/3. Does the spark tester spark on the misfiring cylinder | -- | System OK | Go to Step 7 | ||||
Does the spark tester spark on the misfiring cylinder | -- | Go to Step 8 | Go to Step 9 | |||||
8 | Test the appropriate ignition control circuit of the ignition coil for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 10 | ||||
9 | Test for an intermittent and for a poor connection at the ignition coil. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 12 | ||||
10 | Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 13 | ||||
11 | Repair an open or high resistance in the ignition 1 voltage circuit of the ignition coil. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 14 | -- | ||||
12 | Replace the ignition coil. Refer to Ignition Coil Replacement . Did you complete the replacement? | -- | Go to Step 14 | -- | ||||
13 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 14 | -- | ||||
14 |
Did you correct the condition? | -- | Go to Step 15 | Go to Step 2 | ||||
15 | Are there any DTCs that have not been diagnosed? | -- | System OK | |||||
