Circuit Description
The powertrain control module (PCM) controls the 6 individual coil assemblies using reference pulses from the crankshaft position (CKP) sensor and other sensor inputs. Ignition 1 voltage is applied to the ignition coil assemblies when the ignition switch is in the ON or START positions. The ignition control module within each coil assembly toggles the primary windings, inducing a high voltage in the secondary windings. The high voltage induced in the secondary windings of the ignition coils is applied through the coil boots to the spark plugs.
Diagnostic Aids
Inspect for the following conditions:
If the operation of the ignition system is intermittent, check for a reliable reference signal from the crankshaft position (CKP) sensor while cranking the engine. The PCM relies on the CKP sensor for engine reference. Without continuous accurate reference signals, there is no reliable spark or fuel injector pulse. The scan tool engine speed display should be more than 200 RPM while cranking. If erratic values, such as sudden spikes in engine speed are displayed, the engine reference signal may not be stable enough for the engine to start and run properly. Inspect the CKP sensor signal circuits for electromagnetic interference (EMI) or poor electrical connections.
A vehicle that starts and runs after being brought to the shop for an engine cranks but will not run concern, 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 engine miss or stall.
An intermittent malfunction may be caused by a condition in the ignition system electrical circuit. Inspect the wiring harness and components for an intermittent condition. Refer to Intermittent Conditions .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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If the PCM does not detect a signal from either CKP sensor, the engine will not start. Damage wiring or a sensor that is disconnect causes this condition. If an engine speed is observed, there is no voltage available to the ignition coils. An open fuse in the supply circuit causes a no start and no communication with the scan tool.
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This step is tests for a condition with the control circuit of the ignition coil. If the voltage is not within the specified range, There is a condition with the control circuit of the ignition coil.
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After replacing the PCM, a new minimum throttle position and idle speed must be established.
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views | ||||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||||
2 |
Important: This diagnostic procedure only diagnosis an inoperative ignition coil or a no start condition. Were you sent here from Engine Cranks but Does Not Start? | -- | Go to Step 4 | Go to Step 3 | ||||||||
3 | Were you sent here from DTC P0301-P0306? | -- | Go to Step 5 | |||||||||
Crank the engine over for 10 seconds, while you observe the engine speed parameter with a scan tool. Is engine speed displayed on the scan tool? | -- | Go to Step 12 | Go to Step 13 | |||||||||
Is the voltage within the specified range? | 6.5-7.5 V | Go to Step 6 | Go to Step 8 | |||||||||
6 | Probe the ignition 1 voltage circuit of the ignition coil with a test lamp connected to a good ground. Does the test lamp illuminate? | -- | Go to Step 7 | Go to Step 11 | ||||||||
7 | Probe the ground circuit of the ignition coil with a test lamp connected to B+. Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 14 | ||||||||
8 | Test the control circuit of the ignition coil for an open, short to ground, short to voltage, or for high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 17 | 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 . Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 15 | ||||||||
10 | Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 16 | ||||||||
11 |
Did you complete the repair? | -- | Go to Step 17 | -- | ||||||||
12 | Repair the open ignition 1 voltage circuit between the splice pack 113 and the fuse. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 17 | -- | ||||||||
13 | Repair the damage circuits of the crankshaft position (CKP) sensor or connect the CKP sensor. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 17 | -- | ||||||||
14 | Repair the open ground circuit of the ignition coil. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 17 | -- | ||||||||
15 | Replace the ignition coil. Refer to the appropriate procedure: Did you complete the replacement? | -- | Go to Step 17 | -- | ||||||||
Did you complete the replacement? | -- | Go to Step 17 | -- | |||||||||
17 | Operate the vehicle in order to verify the repair Does a driveability condition still exist? | -- | Go to Step 2 | Go to Step 18 | ||||||||
18 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||||
