P1350

DTC P1350:

Ignition Control Wiring Schematic:

CIRCUIT DESCRIPTION
Ignition control (IC) spark timing is provided by the Powertrain Control Module (PCM) on CKT 423. Inputs from a number of engine sensors allow the PCM to correctly calculate optimum spark timing. Engine load is calculated from the Mass Air Flow (MAF) sensor, engine RPM is derived from the 3X crankshaft position sensor, engine operating temperature from Engine Coolant Temperature (ECT) and Intake Air Temperature (IAT) sensors and engine knock activity from the knock sensor. Other engine functions modify spark to a lesser degree such as Torque Converter Clutch (TCC) engagement and Exhaust Gas Recirculation (EGR) activity.

The bypass circuit controls an internal switch in the electronic Ignition Control Module (ICM). Unless the vehicle is in backup spark (base timing mode), the bypass circuit will have 5 volts applied to it. This 5 volt signal from the PCM allows a solid state switch to direct the IC timing pulses to the ICM for sequencing and energizing the coil packs. If the bypass circuit is not energized, the IC pulses from the ICM are shunted to ground and the electronic ICM uses it's own base timing schedule to time and energize the coil packs.

DIAGNOSTIC TROUBLE CODE (DTC) P1350 WILL SET WHEN
Ignition Control (IC) pulses are detected on CKT 423 when the vehicle is in bypass (no voltage applied to bypass should allow IC pulses to be grounded by the electronic ICM). The test will either pass or fail within the first 100 milli seconds of engine running. If it passes, the test will not run until the next key cycle.

ACTION TAKEN (PCM WILL DEFAULT TO)
The PCM will allow the electronic ignition control module to control timing using it's own base timing schedule. The Malfunction Indicator Lamp (MIL) will become illuminated.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. This test confirms DTC P1350 and that the fault causing the DTC is present.
2. Checks for a normal IC ground path through the ignition control module. A DTC P1350 indicates the PCM has detected an open or short to voltage in the IC circuit, or a short to voltage in the bypass circuit. An IC CKT 423 shorted to ground will also read less than 500 ohms; however, this should set a DTC P1361.

DIAGNOSTIC AIDS
The scan tool does not have any ability to help diagnose a DTC P1350 problem.
Refer to "Intermittents" in Diagnosis by Symptom. - Intermittent Malfunctions

Ignition Control Line
When CKT 423 is shorted voltage or open during crank will set DTC 1350 also if CKT 424 is shorted to voltage during crank DTC 1350 will set.

Ignition Control Bypass Line
During engine run operation CKT 424 opens or shorts to ground DTC 1361 will set. When DTC 1361 is stored, DTC 1350 will not be set. If DTC 1350 is stored, DTC 1361 also can be set.