Input Rationality

While input signals to PCM are constantly being monitored for electrical opens and shorts, they are also tested for rationality. This means that input signal is compared against other inputs and information to see if it makes sense under current conditions. PCM sensor inputs that are checked for rationality include:

• Manifold Absolute Pressure (MAP) Sensor
• Oxygen Sensor (O2S)
• Engine Coolant Temperature (ECT) Sensor
• Camshaft Position (CMP) Sensor
• Vehicle Speed Sensor
• Crankshaft Position (CKP) Sensor
• Intake Air Temperature (IAT) Sensor
• Throttle Position (TPS) Sensor
• Ambient/Battery Temperature Sensors
• Power Steering Switch
• Oxygen Sensor Heater
• Engine Controller
• Brake Switch
• Leak Detection Pump Switch
• P/N Switch
• Trans Controls