Circuit Description
The Electronic Ignition (EI) System uses a waste spark method of spark distribution. The crankshaft position (CKP) sensor sends reference pulses to the engine control module (ECM). The ECM then triggers the EI system ignition coil. Once the ECM triggers the ignition coil, both of the connected spark plugs ignite at the same time. One cylinder is on its compression stroke at the same time that the other is on the exhaust stroke, resulting in lower energy needed to ignite the spark plug in the cylinder on its exhaust stroke. This leaves the remainder of the high voltage to be used to ignite the spark plug in the cylinder on its compression stroke. The ignition coil consists of the following circuits:
| • | The ignition 1 voltage |
| • | The ignition control 1 and 4 |
| • | The ignition control 2 and 3 |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step tests for a short to ground in the ignition 1 voltage circuit.
-
This step tests for a fault in the ignition 1 voltage circuit. It is necessary to command the fuel pump relay ON, because the fuel pump relay supplies the voltage to the ignition coil.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connect End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | |
2 |
Important: Do not perform this diagnostic procedure if you were not sent here from a misfire DTC or the Engine Cranks but Does Not Run diagnostic. Attempt to start the engine. Does the engine start and run? | -- | Go to Step 3 | Go to Step 4 |
3 | Observe the misfire current counters with a scan tool. Does the scan tool display any misfire current counters incrementing? | -- | Go to Step 7 | Go to Intermittent Conditions |
Inspect the fuse that supplies the ignition 1 voltage to the ignition coil. Is the fuse open? | -- | Go to Step 9 | Go to Step 5 | |
Does the test lamp illuminate? | -- | Go to Step 6 | Go to Step 8 | |
Test for high resistance in the ignition 1 voltage circuit of the ignition coil. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Is the resistance more than the specified value? | 4 ohms | Go to Step 10 | Go to Step 11 | |
7 | 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 12 | Go to Step 11 |
8 | Repair the open in the ignition 1 voltage circuit of the coil. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 12 | -- |
9 |
Important: The ignition 1 voltage circuit is shared with other components. Review the electrical schematic and diagnose the shared circuits and components.
Did you complete the repair? | -- | Go to Step 12 | -- |
10 | Repair the 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 12 | -- |
11 | Replace the ignition coil. Refer to Ignition Coil Replacement . Did you complete the replacement? | -- | Go to Step 12 | -- |
12 |
Did you correct the condition? | -- | Go to Step 13 | Go to Step 2 |
13 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |
