Circuit Description
The ignition control module (ICM) has independent power and ground circuits. The circuits between the ICM and the powertrain control module (PCM) consists of the following circuits:
| • | The ignition control (IC) timing signal |
| • | The IC timing control |
| • | The low resolution engine speed signal |
| • | The medium resolution engine signal |
| • | The camshaft position signal |
| • | The low reference |
Both the camshaft position (CMP) sensor and crankshaft position (CKP) sensor signals are input directly to the ICM. The ICM sends 3X signals to the PCM and controls the timing advance during engine cranking. The timing advance changes to PCM control after the following actions occur:
| • | The PCM receives the second 3X signal |
| • | The PCM applies 5 volts to the ignition control (IC) timing signal circuit. |
If the PCM detects an open in the IC timing control circuit, DTC P1351 sets.
Conditions for Running the DTC
The engine speed is more than 600 RPM.
Conditions for Setting the DTC
| • | The PCM detects an open in the IC timing control circuit. |
| • | The condition is present for 300 3X reference periods, 100 crankshaft revolutions. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
| • | The engine will start and may run with the ICM controlling spark timing. |
| • | If the condition is intermittent, 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 |
Did the DTC fail this ignition? | -- | Go to Step 3 | Go to Intermittent Conditions |
3 |
Is the voltage within the specified value? | 20-40 mV | Go to Step 5 | Go to Step 4 |
4 |
Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 6 |
5 | Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8 |
6 | Test for an intermittent and for a poor connection at the ICM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 7 |
7 | Replace the ICM. Refer to Ignition Control Module Replacement . Did you complete the replacement? | -- | Go to Step 9 | -- |
8 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 9 | -- |
9 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 10 |
10 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |
