Analog Volt-Ohmmeter (VOM)

1)  Turn ignition off. To initiate KOEO self-test, connect a jumper wire from STI terminal of self-test connector to ground. The STI connector is located at the left rear of the engine compartment. See Figure and Figure .

2)  Set VOM to 0-20V DC range. Connect positive (+) lead of VOM to STO terminal of self-test connector. See Figure and Figure . Connect the negative (-) test lead to engine ground.

3)  Turn ignition on, and observe voltmeter. Count voltmeter needle sweeps (between 0-12 volts) to determine code. See Fig 1 .

4)  If no code is present, go to step 6). If code(s) is present, record code(s). Turn ignition off, and go to next step.

5)  Erase code(s) from ECA memory. See CLEARING CODES under SELF-DIAGNOSTIC SYSTEM. Repeat step 3) to identify hard faults. If code(s) does not reappear, fault is intermittent. Go to step 8) to begin KOER self-test. If code(s) reappears, indicating hard fault, repair fault as necessary. Refer to CODE REFERENCE CHART  to determine the correct CIRCUIT TEST to perform. Go to step 7).

6)  If engine starts, go to step 8) to begin KOER self-test. If engine does not start, go to BASIC TESTING article in the ENGINE PERFORMANCE Section.

7)  Repeat step 5) until no code appears. Terminate KOEO self-test by turning ignition off and disconnecting STI jumper wire from ground. Go to next step to begin KOER self-test.

8)  Start and operate engine at 2000 RPM for 2 MINUTES to ensure EGO sensor is operating. Ensure vehicle is at normal operating temperature. Turn ignition off. Jumper STI connector to ground to activate KOER self-test. Turn ignition on, and wait 10 SECONDS.

9)  Start engine and allow it to idle. Ensure VOM is connected as described in step 2). Record all codes displayed, and repair fault as necessary. Refer to CODE REFERENCE CHART  to determine the correct CIRCUIT TEST to perform. If no code is present, go to ANALOG VOLT-OHMMETER (VOM) under SWITCH MONITOR TEST.

Fig 1: Reading Code Using Analog Voltmeter

Courtesy of FORD MOTOR CO.