Circuit Description
The ignition control (IC) module has independent power and ground circuits. The circuits between the IC module and the powertrain control module (PCM) consist of the following circuits:
| • | The IC timing signal |
| • | The IC timing control |
| • | The low-resolution engine speed signal |
| • | A low reference signal |
The IC module sends 3X signals to the PCM. The IC module controls the timing advance during engine cranking. The timing advance changes to PCM control after the following actions:
| • | The PCM receives the second 3X signal. |
| • | The PCM applies 5-volts to the IC timing signal circuit. |
Diagnostic Aids
An arcing spark plug wire or an arcing ignition coil to the IC module may cause a stall, misfire or a no start condition.
For an intermittent condition refer to Intermittent Conditions .
Step | Action | Values | 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-Engine Controls? | -- | Go to Step 2 | |||||||||||
2 | Attempt to start the engine. Does the engine start and run? | -- | Go to Step 3 | Go to Step 4 | ||||||||||
3 |
Is the resistance within the specified range? | 800-1200 ohms | Go to Step 4 | Go to Step 28 | ||||||||||
4 |
Does the scan tool indicate a 3X crank sensor signal present? | -- | Go to Step 5 | Go to Step 11 | ||||||||||
5 |
Did you observe any non-sparking cylinders? | -- | Go to Step 6 | Go to Step 9 | ||||||||||
6 |
Important: An arching spark plug wire or an arching ignition coil to the ignition control (IC) module may cause a stall or a no start condition.
Did you find and correct the condition? | -- | Go to Step 32 | Go to Step 7 | ||||||||||
7 | Test the resistance of the spark plug wires. Is the resistance more than the specified value? | 9868 ohms per meter (3,000 ohms per foot) | Go to Step 30 | Go to Step 8 | ||||||||||
8 | Measure the secondary resistance of the ignition coils. Is the resistance within the specified range? | 5,000-8,000 ohms | Go to Step 25 | Go to Step 29 | ||||||||||
9 |
Did you find and correct the condition? | -- | Go to Step 32 | Go to Step 10 | ||||||||||
10 |
Did you find the problem? | -- | Go to Step 31 | Go to Diagnostic Aids | ||||||||||
11 |
Does the test lamp illuminate? | -- | Go to Step 12 | Go to Step 24 | ||||||||||
12 | Connect a test lamp between the IC module ignition 1 voltage circuit and the IC module ground circuit. Does the test lamp illuminate? | -- | Go to Step 13 | Go to Step 26 | ||||||||||
13 | Test for an intermittent and for a poor connection at the ICM. 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 32 | Go to Step 14 | ||||||||||
14 |
Does the test lamp illuminate? | -- | Go to Step 17 | Go to Step 15 | ||||||||||
15 | Probe the CKP sensor 1 signal circuit of the CKP sensor B with a test lamp connected to a good ground. Refer to Troubleshooting with a Test Lamp and Probing Electrical Connectors in Wiring Systems. Does the test lamp illuminate? | -- | Go to Step 18 | Go to Step 16 | ||||||||||
16 |
Is the resistance between the specified value? | 800-1200 ohms | Go to Step 27 | Go to Step 19 | ||||||||||
17 | Test the CKP sensor 1 signal circuit for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 32 | Go to Step 20 | ||||||||||
18 | Test the CKP sensor 1 signal circuit for a short to voltage. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 32 | Go to Step 20 | ||||||||||
19 | Test the CKP sensor B circuits for the following conditions:
Did you find and correct the condition? | -- | Go to Step 32 | Go to Step 20 | ||||||||||
20 | Test for an intermittent and for a poor connection at the ICM. 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 32 | Go to Step 21 | ||||||||||
21 | 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 32 | Go to Step 22 | ||||||||||
22 |
Did you find and correct the condition? | -- | Go to Step 32 | Go to Step 23 | ||||||||||
23 | Visually inspect the reluctor wheel for the following conditions:
Refer to Crankshaft and Bearing Removal in Engine Mechanical. Did you find and correct the condition? | -- | Go to Step 32 | Go to Step 28 | ||||||||||
24 |
Did you complete the repair? | -- | Go to Step 32 | -- | ||||||||||
25 |
Does the test lamp flash continuously while the engine is being cranked? | -- | Go to Step 29 | Go to Step 27 | ||||||||||
26 | Repair the open in the IC module ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 32 | -- | ||||||||||
27 | Replace the IC module. Refer to Ignition Control Module Replacement . Did you complete the replacement? | -- | Go to Step 32 | -- | ||||||||||
28 | Replace the CKP sensor B. Refer to Crankshaft Position Sensor Replacement . Did you complete the replacement? | -- | Go to Step 32 | -- | ||||||||||
29 | Replace the affected Ignition Coils. Refer to Ignition Coil Replacement . Did you complete the replacement? | -- | Go to Step 32 | -- | ||||||||||
30 | Replace the Spark Plug Wires. Refer to Spark Plug Wire Replacement . Did you complete the replacement? | -- | Go to Step 32 | -- | ||||||||||
31 | Replace the Spark Plugs. Refer to Spark Plug Replacement . Did you complete the replacement? | -- | Go to Step 32 | -- | ||||||||||
32 |
Does the vehicle operate normally, with no MIL? | -- | System OK | Go to Step 2 | ||||||||||
