Circuit Description

The DTC P1500 Start Switch Circuit diagnostic monitors the voltage signal that is sent from the ignition switch when starting the engine. When the engine is being cranked, battery voltage is applied to the Powertrain Control Module (PCM). The starter signal is mainly used to increase the fuel injection volume for the starting injection control. This signal passes through the Transmission Range (TR) switch or the Clutch Pedal Position (CPP) switch. If this signal is not detected during engine cranking, the PCM will still allow the engine to start.