ECU Power Transistor and Control Relay

CONTROL RELAY INSPECTION

Caution: When applying battery voltage directly, make sure that it is applied to correct terminal. Otherwise, the relay could be damaged.

Note: Failure of the control relay prevents power supply to the fuel pump. injectors and engine control unit, resulting in start failure.

(1) Check continuity between terminals for both when the relay coil is energized and when not.

Note: In the following tables, the arrows indicate direction of current flow. Confirm circuit tester polarity before checking continuity.





- Coils L(1) and L(2)

Note: "Energized" means voltage applied across terminals 6 and 7.

- Coil L(3).





Note: "Energized" means voltage applied across terminals 8 and 6.





(2) If the result is not satisfactory, replace the control relay.

POWER TRANSISTOR INSPECTION

(1) Disconnect the power transistor connector.









(2) Connect a power supply of 1.5 V to terminals l (+) and 2 (-) of the power transistor and then check for continuity between terminals 3 and 2 under power ON and power OFF conditions.





Note:
(1) For continuity check, use an analog type circuit tester.
(2) When checking the continuity, connect the circuit tester to terminal 2 on the positive side and terminal 3 on the negative side.