For ignition control circuit schematics, refer
to
Cell 21: Ignition Controls - Odd
or
Cell 21: Ignition Controls - Even
.
Circuit Description
A Crankshaft Position (CKP) sensor determines the engine crankshaft position. The sensor is mounted and protrudes into the right side of the engine block. The sensor is near a slotted wheel on the crankshaft. The rotation of the slotted wheel causes a magnetic flux change in the sensor. This produces a voltage signal from the electronic Ignition Control Module (ICM). The signal creates the reference pulses needed by the Powertrain Control Module (PCM). These signals trigger the correct ignition coil to fire, at the correct time.
The ignition system on this engine uses an individual ignition coil/module for each cylinder. The PCM controls the ignition system operation. There are eight Ignition Control (IC) circuits, one per cylinder, that connect the PCM and the ignition coil/modules. Each ignition coil/module has a power feed, a chassis ground circuit, and a reference low circuit. The PCM causes a spark to occur by grounding the IC circuit, which signals the ignition module to trigger the ignition coil and fire the spark plug. The PCM controls the sequencing and timing.
Diagnostic Aids
Important: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.
The following may cause an intermittent:
| • | Check for poor connections. Check for adequate terminal tension. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems. |
| • | Corrosion |
| • | Mis-routed harness |
| • | Rubbed through wire insulation |
| • | Broken wire inside the insulation |
For an intermittent condition, refer to Symptoms .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Monitoring the misfire current counters determines if a fault is present.
-
A good indication that the fuse is open is all the misfire current counters are incrementing on one side of the engine. Inspect the ignition feed circuit for a grounded circuit.
-
If the fuse is open and the ignition coil/module circuits are OK, inspect the injector circuits for being grounded. The INJ A fuse and INJ B fuse feed the ignition coil/module circuits and injector circuits.
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||
2 | Are DTCs P0335, P0336, P0351-P0358 set? | -- | Go to Applicable DTC Table | |||||
|
Important:
Are any of the Misfire Cur. counters incrementing? | -- | Go to Diagnostic Aids | ||||||
Are the misfire current counters incrementing for most cylinders on one bank of the engine? | -- | |||||||
5 |
Does the test lamp illuminate? | -- | ||||||
6 | Probe the ignition feed circuit at the ignition coil/module electrical connector to the ignition coil/module ground circuit using the test lamp J 35616-200 . Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate? | -- | ||||||
7 | Probe the ignition feed circuit at the ignition coil/module electrical connector to the ignition coil/module reference low circuit using the test lamp J 35616-200 . Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate? | -- | ||||||
Did you find and correct the condition? | -- | System OK | ||||||
9 | Repair the open in the ignition feed circuit between the fuse block and the splice. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | System OK | -- | ||||
10 |
Does the test lamp illuminate? | -- | ||||||
11 | Repair the open circuit between the splice and the ignition coil/module connector. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | System OK | -- | ||||
12 | Repair the open ignition feed circuit between the fuse block (open fuse) and splice. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | System OK | -- | ||||
13 |
Does the test lamp illuminate? | -- | ||||||
14 |
Did you find and correct the condition? | -- | System OK | |||||
15 | Repair the open ground circuit between the main 8-way connector and the ignition coil/module connector. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | System OK | -- | ||||
16 | Repair the open ground circuit between the ground and the main 8-way connector. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | System OK | -- | ||||
17 |
Does the test lamp illuminate? | -- | ||||||
18 |
Did you find and correct the condition? | -- | System OK | |||||
19 | Repair the open reference low circuit between the main 8-way connector and the ignition coil/module connector. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | System OK | -- | ||||
20 | Repair the open reference low circuit between the PCM and the splice. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | System OK | -- | ||||
21 |
Did you find a condition and correct it? | -- | System OK | |||||
22 | Replace ignition coil/module. Refer to Ignition Coil Replacement in Engine Electrical. Is the action complete? | -- | System OK
| -- |
