Refer to Engine Controls Schematics .
Circuit Description
The ignition control (IC) Module sends signals that the PCM requires for fuel control and spark advance calculations. At the start of engine crank, the IC Module controls spark advance. When the second 3X reference pulse is recognized by the PCM, the PCM applies 5.0 volts to the Bypass circuit, commanding the IC Module to switch spark advance to PCM control . If the PCM detects an open in the IC circuit, DTC P1351 will set. The engine will start and may run with IC Module controlling spark timing.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
| • | The PCM detects an open in the IC circuit. |
| • | The condition is present for 300 3X reference periods (100 crankshaft revolutions). |
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
Inspect for the following conditions:
Many situations may lead to an intermittent condition. Perform each inspection or test as directed.
Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Loose terminal connection |
| - | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| - | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
| • | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||
2 |
Does the DMM display a resistance below the specified value? | 500ohms | ||
3 |
Did you find and correct the condition? | -- | ||
4 | Test for poor terminal connections at the PCM. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
5 | Test for poor terminal connections at the ignition control (IC) module. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition? | -- | ||
6 | Replace the Ignition Control Module. Refer to Ignition Control Module Replacement . Did you complete the replacement? | -- | -- | |
7 |
Important: : The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | -- | |
8 |
Does the scan tool indicate DTC P1351 failed this ignition? | -- | System OK |
