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 Throttle Position Sensor (TPS) 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.