Circuit Description

The 2-speed fuel pump is operated by the fuel pump ECU which receives a signal from ECM to compensate fuel pressure for start, light engine load or high engine load. DTC is set during the following 3 conditions:

1. Open or short in fuel pump circut is detected for 1 second or more with engine speed of 1000 RPM or less.
2. Open in input circuit of fuel pump ECU with engine speed of 1000 RPM or less.
3. Open or short in fuel pump ECU diagnostic signal line with engine speed of 1000 RPM or less. Possible causes for all conditions are:
   • Fuel pump ECU open or short circuit.
   • Fuel pump ECU.
   • ECM power supply circuit.
   • Fuel pump.
   • ECM.