Refer to Engine Controls Schematics
Ignition Control Inputs
.
Circuit Description
The ignition control module (ICM) sends signals that the powertrain control module (PCM) requires for fuel control and spark advance calculations. At the start of engine crank, the ICM controls spark advance (bypass mode.) When the second 3X reference pulse is recognized by the PCM, the PCM applies 5 volts to the bypass circuit, commanding the ICM to switch the spark advance to PCM control (IC mode). If the PCM detects an open in the bypass circuit, DTC P1351 will set. The engine will start and may run in bypass mode timing.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
The PCM detects an open in the IC circuit.
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has run and passed. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using a scan tool. |
Diagnostic Aids
Check for the following conditions:
| • | Check for a faulty connection at the PCM. Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connections. Use a corresponding mating terminal to test for proper terminal tension. |
| • | Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the ICM, turn the ignition ON and observe a digital multimeter connected between the IC circuit and ignition positive feed voltage while moving the connectors and wiring harnesses related to the ICM. A change in voltage will indicate the location of the malfunction. |
Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
Test Description
The numbers below refer to the step numbers on the diagnostic table:
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain On Board Diagnostic (OBD) System Check performed? | -- | ||
2 |
Is the voltage within the specified range? | 20-40 mV | ||
3 |
Was a problem found? | -- | ||
4 |
Was a problem found? | -- | ||
5 |
Was a problem found? | -- | ||
6 | Replace the ignition control module. Refer to Ignition Control Module Replacement . Did you complete the repair? | -- | -- | |
|
Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the repair? | -- | -- | ||
8 |
Does the scan tool indicate DTC P1351 failed this ignition? | -- | System OK |
