Circuit Description

An ignition voltage circuit and a ground circuit are supplied to the fuel pump control module. When the ignition switch is in the ON position, the fuel pump control module turns ON the fuel pump to full power within 24 milliseconds. This facilitates rapid fuel prime for 500 milliseconds. The engine control module (ECM) supplies a pulse width modulated (PWM) signal to the fuel pump control module on the fuel pump relay control circuit. The fuel pump control module varies the voltage to the fuel pump based on the signal from the ECM. If the fuel pump control module receives no fuel pump control signal from the ECM within 500 milliseconds, the fuel pump control module will turn OFF output to the fuel pump.

At idle speed, the fuel pump control module sets the voltage potential to the fuel pump to 9.5 volts. This reduces fuel pump noise and vehicle system power requirements. When higher fuel volume is required, such as engine operation above idle, the fuel pump control module increases the voltage potential to the fuel pump to battery voltage.

The fuel pump control module also supplies the fuel pump speed output circuit and the fuel pump motor low reference circuit, which allows for enhanced fuel pump diagnostics. Therefore, the fuel pump control module is capable of diagnosing itself, the fuel pump relay control circuit, and the fuel pump performance. The diagnostic information is communicated from the fuel pump control module to the ECM through the fuel pump speed control feedback signal circuit.

If the fuel pump control module detects a high voltage between the fuel pump control module and the fuel pump, DTC P0232 sets.