FRT Sensor PWM Circuit (JL4)

The fuel rail temperature and pressure sensor information is required by the PCM for fuel trim adjustment. The PCM does not have the ability to supply and monitor the FRT sensor. The FICM performs this task by supplying the FRT sensor a low reference and signal circuit. The signal voltage of the FRT sensor is converted to an independent PWM signal. The PWM signal is sent to the PCM through a dedicated circuit. The PCM converts the PWM signal into a temperature value. The FICM also performs diagnosis of the FRT circuits as well as internal FICM diagnostic information. The FICM diagnostic information is converted into a PWM signal. The FICM PWM signal is sent to the PCM through a dedicated circuit. On vehicles equipped with JL4, the PCM directly supplies a 5 volt reference, low reference and signal circuit to the FRP sensor.