ECM Power and Ground Supply Circuits

OPERATION

While the ignition switch is ON, battery power supply is supplied to the engine control module, injectors, volume air flow sensor, etc.

When the ignition switch is switched ON, current flows from the ignition switch, via the MFI relay coil to ground.

As a result, the MFI relay switch is switched ON, and power is supplied, by way of the MFI relay switch, from the battery to the engine control module.

INSPECTION








MULTIPORT FUEL INJECTION RELAY

Fig. 1 Control Relay Test:

Fig. 1

COMPONENT TEST
1. Remove the control relay.
2. Using an Ohm meter, check the resistance between the terminals as shown in FIG. 1.

Fig. 2 Control Relay Test:

Fig. 2

3. Using an Ohm meter, check the resistance terminals 1 and 4, when Voltage is supplied and not supplied between terminals 6 and 7 as shown in FIG. 2.

Fig. 3 Control Relay Test:

Fig. 3

4. Using an Ohm meter, check the resistance terminals 2 and 4, when Voltage is supplied and not supplied between terminals 6 and 8 as shown in FIG. 3
5. If not as specified, replace multiport fuel injection relay.

ENGINE CONTROL MODULE POWER GROUND





OPERATION

Grounding of the engine control module.

TROUBLESHOOTING HINTS

If there is incorrect or incomplete contact of the engine control module's ground line, the engine control module will not function correctly.





HARNESS INSPECTION