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Home >> Ford >> 1989 >> Bronco 5.0 N, Standard, M5OD-R2 >> Repair and Diagnosis >> Engine Performance >> Theory and Operation >> EEC-IV Theory/Operation >> Quick Test >> Key On Engine Off (KOEO) Self-Test >> Test Procedure

Test Procedure

  1. Turn ignition switch to "OFF" position. Ensure all procedures of PREPARATION & EQUIPMENT HOOK-UP have been followed. Engine should be at normal operating temperature.
  2. Turn ignition on. On 7.3L diesel engines, depress the throttle, it must remain depressed throughout the entire KOEO test. On 4.9L engines with manual transmissions, the clutch must be depressed throughout the entire test. If using an analog VOM or the "Check Engine" (MIL) light, connect a jumper wire from Self-Test Input (STI) pigtail to pin No. 2 (Signal Return) on Self-Test connector, this will activate the KOEO Self-Test. If Star Tester is being used latch center button in down position at this time.
  3. The ECA will run through a test cycle, opening and closing various solenoids and switches. After the completion of the test cycle the codes will appear. Record all codes.
    NOTE: DO NOT depress the throttle during the KOEO SELF-TEST. Ensure ignition switch is in the "ON" position before jumping STI connector to pin No. 2 of the Self-Test connector.
  4. The first set of codes to appear are the KOEO SELF-TEST codes, they will be repeated twice, followed by the Separator Pulse signal and then the CONTINUOUS MEMORY codes. These codes will also be repeated twice.
  5. A KOEO Code 11 indicates the system has passed the self-test. A Code 11 must be present before continuing. Disregard any Continuous Memory Codes at this time. Service KOEO codes in the order they appear. Refer to the KOEO SELF-TEST CODES table to find the appropriate CIRCUIT TEST. After each repair, repeat KOEO SELF-TEST until a Code 11 is displayed.
  6. If no KOEO codes are displayed, a Code 11 (pass code) and a Code 10 (separator pulse) are present, record the Continuous Memory Codes. Service only the KOEO CONTINUOUS MEMORY CODE EXCEPTIONS at this time. All other Continuous Memory Codes will be serviced after a Code 11 is displayed during the KOER SELF-TEST.
KOEO CONTINUOUS MEMORY CODE EXCEPTIONS

Application/Code Circuit Test & Step
2.3L
11-10-28 or 48 D12 (13)
11-10-88 D12 (14)
All Engines
11-10-15 D15 (1)
Vehicles With E4OD Transmissions
11-10-49, 56, 59, 62, 66, 67, 69 or 99 D25 (30)
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