Deceleration Mode

This is a CLOSED LOOP mode. During deceleration the following inputs are received by the PCM:

• A/C Status
• Battery Voltage
• Inlet/Intake Air Temperature
• Engine Coolant Temperature
• Crankshaft Position (Engine Speed)
• Exhaust Gas Oxygen Content (Upstream Heated Oxygen Sensor)
• Knock Sensor
• Manifold Absolute Pressure
• Throttle Position Sensor
• IAC motor (solenoid) control changes in response to MAP sensor feedback.

The PCM may receive a closed throttle input from the (TP) sensor when it senses an abrupt decrease in manifold pressure. This indicates a hard deceleration (Open Loop). In response, the PCM may momentarily turn off the injectors. This helps improve fuel economy, emissions and engine braking.