Refer to
IC Module, CMP and CKP Sensors
in Engine Controls Schematics.
Circuit Description
The ignition control module (ICM) sends signals that the PCM requires for fuel control and spark advance calculations. At the start of engine crank, the ICM controls the spark advance. This is called the 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. This is called the IC mode. If the PCM detects an open in the IC 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 illuminates the MIL during the second consecutive trip in which the diagnostic test runs and fails. |
| • | The PCM stores the conditions that were present when the DTC set as Freeze Frame and Fail Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns the MIL OFF during the third consecutive trip in which the diagnostic runs and passes. |
| • | The history DTC clears after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using the scan tool Clear Information function or by disconnecting the PCM battery feed. |
Diagnostic Aids
Check for the following conditions:
| • | A faulty connection at the PCM or ICM--Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. Use a corresponding mating terminal to test for proper terminal tension. |
| • | A damaged harness--Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the ICM, turn the ignition ON and observe a DMM connected between the IC circuit and B+ while moving connectors and wiring harnesses related to the ICM. A change in voltage will indicate the location of the malfunction. |
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set. This may assist in diagnosing the condition.
Test Description
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 |
Does the DMM display 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 . Is the action complete? | -- | -- | |
|
Important: Replacement PCM must be reprogrammed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | ||
8 |
Does the scan tool indicate DTC P1351 failed this ignition? | -- | System OK |
