Circuit Description
The electronic ignition system uses an individual ignition coil for each cylinder. The powertrain control module (PCM) controls the ignition operation through eight individual ignition control (IC) circuits. Each bank of four ignition coils is connected to the PCM, power, or ground by the following circuits:
| • | Low reference |
| • | Chassis ground |
| • | Ignition 1 voltage |
| • | The appropriate IC circuit |
The PCM triggers an ignition coil by grounding the appropriate IC circuit using information from the crankshaft position (CKP) and camshaft position (CMP) sensors.
Diagnostic Aids
Important:
• Remove any debris from the PCM connector surfaces before servicing the
PCM. Inspect the PCM connector gaskets if you diagnose or replace the
PCM. Verify that the gaskets are installed correctly. The gaskets
prevent water intrusion into the PCM. • For any test that requires probing the PCM or component harness connectors,
use the Connector Test Adapter Kit J 35616
. Using this kit prevents any damage to the harness connector
terminals. Refer to
Using Connector Test Adapters
in Wiring Systems.
Using the Freeze Frame/Failure Records may aid in locating an intermittent condition. If you cannot duplicate the condition, the information included in the Freeze Frame/Failure Records can help determine how many miles were driven since the condition occurred. Operate vehicle within the same Freeze Frame conditions which failed the test in the previous ignition cycle.
Inspect for the following conditions:
| • | The load |
| • | The RPM |
| • | The temperature |
For an intermittent condition, refer to Intermittent Conditions .
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 more than 2 of the Misfire Current Counters are incrementing on one side of the engine. Inspect the ignition 1 voltage circuit for a grounded circuit.
-
If the fuse is open and no condition can be found with the ignition coil module circuits, inspect the injector circuits for being grounded.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |
2 | Are any of these DTCs set: P0200, P0300, P0335, P0336, P0351-P0358? | Go to Step 3 | |
|
Important: This diagnostic test assumes that there are not any injector circuit malfunctions or mechanical malfunctions. If you were not referred to this diagnostic test from DTC P0300, refer DTC P0300 to before proceeding with this table. If more than 1 cylinder is misfiring on 1 side of the engine, inspect the ignition coil module ground circuit for an open.
Do any of the Misfire Current counters increment? | Go to Step 4 | Go to Intermittent Conditions | |
Do the Misfire Current Counters increment for 2 or more cylinders on 1 bank of the engine? | Go to Step 8 | Go to Step 5 | |
5 |
Does the test lamp illuminate? | Go to Step 6 | Go to Step 10 |
6 | Using the test lamp probe the ignition 1 voltage circuit at the electrical connector of the ignition coil to the ignition coil ground circuit. Does the test lamp illuminate? | Go to Step 7 | Go to Step 13 |
7 | Connect the test lamp and probe the ignition 1 voltage circuit to the low reference circuit of the ignition coil. Does the test lamp illuminate? | Go to Step 21 | Go to Step 17 |
Did you find and correct the condition? | Go to Step 23 | Go to Step 9 | |
9 | Repair the open in the ignition 1 voltage circuit between the fuse block and the splice. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 23 | -- |
10 |
Does the test lamp illuminate? | Go to Step 11 | Go to Step 12 |
11 | Repair the open circuit between the main 8-way harness connector and the ignition coil connector. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 23 | -- |
12 | Repair the open ignition 1 voltage circuit between the fuse block, the open fuse, and the 8-way harness connector of the ignition coils. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 23 | -- |
13 |
Does the test lamp illuminate? | Go to Step 14 | Go to Step 16 |
14 |
Did you find and correct the condition? | Go to Step 23 | Go to Step 15 |
15 | Repair the open ground circuit between the main 8-way connector and the ignition coil connector. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 23 | -- |
16 | Repair the open ground circuit between the ground and the main 8-way connector. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 23 | -- |
17 |
Does the test lamp illuminate? | Go to Step 18 | Go to Step 20 |
18 |
Did you find and correct the condition? | Go to Step 23 | Go to Step 19 |
19 | Repair the open low reference circuit between the main 8-way connector and the ignition coil connector. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 23 | -- |
20 | Repair the open low reference circuit between the PCM and the splice. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 23 | -- |
21 |
Did you find and correct the condition? | Go to Step 23 | Go to Step 22 |
22 | Replace the ignition coil. Refer to Ignition Coil Replacement . Did you complete the replacement? | Go to Step 23 | -- |
23 |
Does the vehicle operate normally, with no MIL illumination and no stored DTCs? | System OK | |
