This multi-purpose relay switches power to vehicle sensors and actuators including airflow sensor, crank angle sensor, idle speed control, injectors and fuel pump, (not all sensors are used on all engines). When ignition switch is turned "ON" position, ECU energizes coils controlling injectors, airflow sensor and idle speed control. When ignition switch is turned to "START" position, ECU energizes coils (through inhibitor switch on automatic transmission) to supply power to fuel pump. Relay failure will cause a no-start condition. For additional testing see appropriate SYSTEM/COMPONENT TESTS article. Refer to the following list:

Fuel Injected, see: I - SYSTEM/COMPONENT TESTS - EFI

Carbureted, see: I - SYSTEM/COMPONENT TESTS - CARBURETED

Fig 1: Typical Fuel Injected Engine Fuel Pressure Testing Connection

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

FUEL PUMP TEST TERMINAL LOCATION

Application	Wire Color	Location
Galant	Yellow/Green	Left rear of engine compartment
Starion	Black/White	Right front of engine compartment
Van/Wagon	Red/Green	Left rear of battery compartment
Montero	Black/White	Behind right kick panel
Sigma	Black/Blue	Left rear engine compartment

FUEL PRESSURE SPECIFICATIONS

Application		psi (kg/cm² )
Regulator Hose On
All Engines		38 (2.7)
Starion		35-38 (2.5-2.7)
Regulator Hose Off
All Other Models		47-50 (3.3-3.5)
Montero		47-53 (3.3-3.5)

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Control Relay

Use the Manual With the Right Hardware

When to See a Mechanic

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