Fuel Pressure-Up System Test
- Ensure coolant temperature switch is operating correctly. Switch is in side of engine block and has a Pink wire attached. There should be no continuity between switch terminal and body when coolant is below 208°F (98°C). There should be continuity between switch terminal and body when coolant is above 220°F (105°C).NOTE: On Land Cruiser, ECU uses signal from coolant temperature switch rather than the coolant temperature sensor to control ground circuit for fuel pressure-up vacuum switching valve.
- Fuel pressure-up system is controlled by ECU through a vacuum switching valve. The vacuum switching valve is fed current through the EFI main relay when the ignition is turned on. ECU controls the ground circuit. ECU will activate vacuum switching valve for 90-180 seconds when restarting engine at normal operating temperature.
- Check operation of vacuum switching valve using 17 as a reference. Switching valve is located on left fender (rear most vacuum switching valve).