Powertrain Control Module (PCM)

The PCM is responsible for maintaining proper spark and fuel injection timing for all driving conditions. To provide optimum driveability and emissions, the PCM monitors input signals from the following components in calculating Ignition Control (IC) spark timing:
^ Engine Coolant Temperature (ECT) sensor
^ Intake Air Temperature (IAT) sensor
^ Mass Air Flow (MAF) sensor
^ Trans range inputs from transaxle range switch
^ Throttle Position (TP) sensor
^ Vehicle Speed Sensor (VSS)

Reference Low Circuits
The reference low circuits provide a common ground between the PCM, and the ignition control modules. These circuits reduce the electrical ground shifts that may occur between the PCM and the ignition control modules. A malfunction in the reference low circuits may cause a poor driveability condition.

Results of Incorrect Operation
An Ignition control circuit that is open, grounded, or short to voltage will set an ignition control circuit DTC. If a fault occurs in the IC output circuit when the engine is running, the engine will experience a misfire. DTCs P0351-P0358 indicate that a malfunction has been detected on an Ignition Control circuit. DTCs P1359 and P1360 will set when the PCM detects random malfunctions in ignition control circuit.