Fuel Pump Feedback

On some models, the fuel pump circuit between the relay and fuel pump is monitored by PCM. This enables PCM to determine when the fuel pump relay is energized and voltage is being delivered to fuel pump. Voltage monitored on this circuit is also used in calculations to determine changes in idle speed, air/fuel ratio and ignition dwell. A failure in this monitored circuit will result in the setting of a related trouble code in PCM memory.