Circuit Description
WARNING: This page is about a different variant/trim than selected.
Each ignition coil supplies secondary voltage to a pair of spark plugs. This is called a waste spark ignition system. The powertrain control module (PCM) supplies a signal on each of the ignition control (IC) timing circuits to the ignition control module (ICM). The ICM fires the correct ignition coil at the correct time based on the signals. The ICM detects if cylinder 1 or cylinder 3 is on the compression stroke by sensing the secondary voltage and polarity of each side of the ignition coil. The ICM detects this voltage with sensing circuitry integrated into each ignition coil. The higher voltage is on the compressing cylinder. This is called compression sense ignition. The ICM provides a synthesized cam signal to the PCM based on these inputs. The PCM uses the cam signals to synchronize fuel injection.
This system consists of the following circuits:
- An ignition voltage circuit
- A ground circuit
- A camshaft position (CMP) sensor signal circuit
- An IC timing control circuit for cylinders #1 and #4
- An IC timing control B circuit for cylinders #2 and #3
Electronic Ignition (EI) System Diagnosis (With Special Tool)
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) Connector End Views or Engine Controls 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 |
|
- | Go to Step 5 | Go to Step 3 |
| 3 | Is the no spark condition only present on one cylinder? | - | Go to Step 15 | Go to Step 4 |
| 4 | Is the no spark condition only present on companion cylinders 1-4 or 2-3? | - | Go to Step 11 | Go to Step 7 |
| 5 | Does the spark tester indicate a bright blue spark on all cylinders? | - | Go to Step 6 | Go to Step 15 |
| 6 |
|
- | System OK | Go to Step 22 |
| 7 |
|
- | Go to Step 8 | Go to Step 18 |
| 8 | Connect a test lamp from the ignition voltage circuit to the ground circuit of the ICM. Does the test lamp illuminate? |
- | Go to Step 9 | Go to Step 19 |
| 9 |
|
3 Ω | Go to Step 10 | Go to Step 20 |
| 10 | Measure the resistance of the ground circuit of the ICM from the harness connector of the ICM to a good ground. Is the resistance less than the specified value? |
3 Ω | Go to Step 11 | Go to Step 21 |
| 11 |
|
- | Go to Step 15 | Go to Step 12 |
| 12 | Does only one of the LEDs flash on the tester? | - | Go to Step 13 | Go to Step 16 |
| 13 |
|
- | Go to Step 14 | Go to Step 16 |
| 14 | Test the IC timing control circuit for the affected coil of the ICM for one of the following conditions:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 26 | Go to Step 17 |
| 15 | Test for shorted terminals or a poor connection at the ignition coil housing. 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 26 | Go to Step 23 |
| 16 | Test for shorted terminals or 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 26 | Go to Step 24 |
| 17 | Test for shorted terminals or poor connections 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 26 | Go to Step 25 |
| 18 | Repair an open or short to ground in the ignition voltage circuit of the ICM. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 26 | - |
| 19 | Repair an open in the ground circuit of the ICM. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 26 | - |
| 20 | Repair the high resistance in the ignition voltage circuit of the ICM. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 26 | - |
| 21 | Repair the high resistance in the ground circuit of the ICM. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 26 | - |
| 22 | Replace the spark plugs. Refer to Spark Plug Replacement
. Did you complete the replacement? |
- | Go to Step 26 | - |
| 23 | Replace the ignition coil housing. Refer to Ignition Coil Housing Replacement
. Did you complete the replacement? |
- | Go to Step 26 | - |
| 24 | Replace the ICM. Refer to Ignition Control Module Replacement
. Did you complete the replacement? |
- | Go to Step 26 | - |
| 25 | 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 26 | - |
| 26 |
|
- | System OK | Go to Step 2 |