Circuit Description
The PCM controls dwell and spark timing during all engine running conditions. The electronic ignition (EI) module charges the coil pack when the PCM supplies 5 volts to the 1/4 coil. The coil will then discharge or fire through its secondary coil towers whenever the voltage supply has been turned OFF by the PCM.
Conditions for Setting the DTC
During cranking the PCM pulses the ignition control (IC) circuit high and low. The PCM monitors the diagnostic feedback circuit to diagnose circuit faults.
Important: IC circuit 1 and 4 are checked continuously whenever the crankshaft position sensor pulses are received by the PCM during cranking mode only.
DTC P0351 will set if there is an open, short to voltage, or short to ground in IC 1 and 4, circuit 423.
OR
DTC P0351 and DTC P1351 will set if there is a short to voltage in IC 1 and 4, circuit 423, when the engine is in cranking mode.
Diagnostic Aids
The IC circuit 1 and 4 consists of an ignition module, circuit 423, and the PCM.
Important: If there is an open in the IC 1 and 4 circuit, a misfire on those cylinders will occur.
| • | A malfunctioning 1 and 4 coil, 1 and 4 secondary wire, or 1 or 4 spark plug will not cause a DTC P0351 and/or P1351 to set. |
| • | A blown EIS fuse will cause a no start condition but an IC 1 and 4 DTC may not set. |
| • | An IC 1 and 4 circuit fault may set a cam missing code DTC P0340. |
| • | If the engine starts with a fault on the IC circuit, a misfire DTC P0300 may also be set. |
