Actron 9640 User Manual

The Output State Options are 

displayed. The fourth option is “High 

Speed Fan.” Select an option and press 

ENTER.

✓

Listen for devices turn on and off.

After a brief Command Sent screen, an 

Output State screen is displayed for the 

duration of the test. Select CHANGE to 

toggle the state to On/Off or QUIT to 

return to the Quick Tests screen.

a 7.3L Powerstroke Diesel engine. 

The KOEO Inj. Buzz is a functional test performed on demand with the ignition 

key ON and Engine OFF. The test determines if the injector circuits and 

solenoids are operating electrically correct and without faults. 

All injectors are buzzed initially (audible feedback of solenoids energizing the 

valves) for approximately 2 seconds. Then each injector will buzz individually 

for approximately 1 second, in numerical order (1 – 8).

Select KOEO Inj. Buzz from the Quick 

Tests screen, press 

ENTER.

Perform the following:

1) Set Parking Brake.
2) Transmission In Park Or Neutral.
3) Turn A/C Off.
4) Start Engine — Let Idle Until Hot.
5) Turn Ign Key Off.
6) Wait 10 Seconds. Turn Key On-Engine Off. (Do Not Start). 

Press 

ENTER to start the test. Listen for 

one long buzz and then 8 short equal 

buzzes as each fuel injector is 

energized. 

Press the 

FUNC key to return to the 

Ford Function List or 

BACK to return to the Quick Tests screen.

Output State Option
` 1)All Off

2)All But Fans/Inj [
3)Low Speed Fan  ~

All But Fans/Inj ?

State: ON

<Change>  Quit  ~

Quick Tests      ? 

 

 

 

KOEO On Demand

]

` KOEO Inj. Buzz   [

KOEO Output State ~

Test In Progress
Approximate
Time Left   3:00
Press BACK to Quit ~