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HOMESERVICE MANUALSFORD1988AEROSTAR VAN PASSENGER, AUTOMATICREPAIR AND DIAGNOSISTRANSMISSIONAUTOMATIC TRANSDIAGNOSIS - A4LDQUICK TESTKOEO SELF-TEST
1988 Ford Aerostar Van Passenger, Automatic

KOEO Self-Test

1988 Ford Aerostar Van Passenger, AutomaticSECTION KOEO Self-Test

Ensure engine is at normal operating temperature. If engine does not start (or stalls after starting), continue KOEO SELF-TEST. DO NOT depress throttle on gasoline engines. Turn ignition off. Wait 10 seconds. Ensure test equipment is properly attached. Turn ignition on (engine off). Record all KOEO and Continuous Memory Codes.

If a Code 11 or 111 (pass code) is not retrieved in KOEO portion of test, service KOEO codes at this time. Service any engine codes recorded before servicing transmission codes (codes No. 86, 89, 566 and 629). If ECA will not output codes, see TESTS W/CODES - EEC-IV article in ENGINE PERFORMANCE section. If service codes are retrieved, observe the following procedures:

  • If CHECK ENGINE or SERVICE ENGINE SOON light is on, service codes in order retrieved.
  • On vehicles equipped with DIS and EDIS ignition systems, see SYSTEM/COMPONENT TESTS article in ENGINE PERFORMANCE if Continuous Memory Code 45, 46, 48, 215, 216, 217, 232 or 238 is retrieved during KOEO SELF-TEST. Repair ignition system as necessary.
  • If vehicle has a no-start condition, go to CIRCUIT TESTS in appropriate TESTS W/CODES - EEC-IV article in ENGINE PERFORMANCE.
  • If vehicle displays a Code 11 or 111 (pass code) and does not have any of symptoms described in previous steps, go to COMPUTED TIMING CHECK  .

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.