Circuit Description
The electronic ignition system uses an individual ignition coil for each cylinder. The powertrain control module (PCM) controls the ignition operation through 8 individual ignition control (IC) circuits. Each bank of four ignition coils is connected to the PCM, power, and ground by the following circuits:
| • | The low reference |
| • | The ground |
| • | The Ignition 1 voltage |
| • | The appropriate IC circuit |
The PCM triggers an ignition coil by grounding the appropriate IC control using information from the crankshaft position (CKP) and camshaft position (CMP) sensors.
Diagnostic Aids
| Important: A missing CMP sensor signal may cause a long crank condition. |
| • | The CKP signal must be available for the engine to start. The CMP signal is not needed to start and operate the engine. The PCM can determine when a cylinder is on either the firing or exhaust stroke by the 24X signal. |
| • | Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM. |
| • | For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections . |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the scan tool display engine RPM? | -- | Go to Step 3 | Go to Step 15 |
3 | Is DTC P0335, P0336, P0351, or P0358 also set? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 4 |
Does the scan tool display any misfire current counters incrementing? | -- | Go to Step 5 | Go to Diagnostic Aids | |
5 | Do the misfire current counters increment for most cylinders on one bank of the engine? | -- | Go to Step 11 | Go to Step 6 |
6 |
Is adequate spark present? | -- | Go to Step 32 | Go to Step 7 |
7 | Measure the spark plug wire resistance. Refer to Spark Plug Wire Inspection . Is the resistance more than the specified value? | 1,000 ohms/ft | Go to Step 31 | Go to Step 8 |
8 |
Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 12 |
9 | Probe the ignition 1 voltage circuit at the ignition coil with a test lamp connected to the ground circuit of the ignition coil. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 13 |
10 | Probe the ignition 1 voltage circuit at the ignition coil with a test lamp connected to the low reference circuit of the ignition coil. Refer to Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate? | -- | Go to Step 19 | Go to Step 14 |
11 | Inspect for an open ENG 1 or ENG 2 fuse. Is the fuse open? | -- | Go to Step 28 | Go to Step 22 |
12 |
Does the test lamp illuminate? | -- | Go to Step 23 | Go to Step 22 |
13 |
Does the test lamp illuminate? | -- | Go to Step 17 | Go to Step 25 |
14 |
Does the test lamp illuminate? | -- | Go to Step 18 | Go to Step 27 |
15 |
Is the difference in the voltage more than the specified value? | 0.5 V | Go to Step 16 | Go to Step 29 |
16 | Test for a short to ground in the CKP 12-volt reference circuit or the camshaft position (CMP) sensor 12-volt reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 34 | Go to Step 21 |
17 | Test for an intermittent and for a poor connection at the ignition coil 8-way connector. 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 34 | Go to Step 24 |
18 | Test for an intermittent and for a poor connection at the ignition coil 8-way connector. 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 34 | Go to Step 26 |
19 | 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 34 | Go to Step 30 |
20 | Test for an intermittent and for a poor connection at the CKP sensor. 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 34 | Go to Step 29 |
21 | Test for an intermittent and for a poor connection at the powertrain control module (PCM). 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 34 | Go to Step 33 |
22 | 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 34 | -- |
23 | Repair the open in the ignition 1 voltage circuit between the splice and the ignition coil connector. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 34 | -- |
24 | Repair the open in the ground circuit between the main 8-way connector and the ignition coil. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 34 | -- |
25 | Repair the open in the ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 34 | -- |
26 | Repair the open low reference circuit between the main 8-way connector and the ignition coil. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 34 | -- |
27 | 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 34 | -- |
28 |
Did you complete the repair? | -- | Go to Step 34 | -- |
29 | Replace the CKP sensor. Refer to Crankshaft Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 34 | -- |
30 | Replace the ignition coil. Refer to Ignition Coil Replacement . Did you complete the replacement? | -- | Go to Step 34 | -- |
31 | Replace the spark plug wire. Refer to Spark Plug Wire Replacement . Did you complete the replacement? | -- | Go to Step 34 | -- |
32 | Replace the spark plug. Refer to Spark Plug Replacement . Did you complete the replacement? | -- | Go to Step 34 | -- |
33 | Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 34 | -- |
34 | Attempt to start the engine. Does the engine start and continue to run? | -- | Go to Step 35 | Go to Step 2 |
35 |
Are there any DTCs that have not been diagnosed? | -- | System OK | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information |
