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HOMESERVICE MANUALSFORD1993PICKUP F250, 2D PICKUP, 5.0 N, STANDARD, M5OD-R2REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT VARIANT/TRIMSECTION 2 (ENGINE CONTROLS - TESTS W/CODES - 4.9L)QUICK TESTKOER SELF-TEST
1993 Ford Pickup F250, 2D Pickup, 5.0 N, Standard, M5OD-R2

KOER Self-Test

1993 Ford Pickup F250, 2D Pickup, 5.0 N, Standard, M5OD-R2SECTION KOER Self-Test
WARNING: This page is about a different variant/trim than selected.

DO NOT enter this test sequence until a Code 11 or 111 (pass code) has been retrieved in KOEO SELF-TEST. If system has not passed KOEO SELF-TEST, codes received from KOER SELF-TEST may not be valid.

Deactivate self-test by removing and reconnecting jumper wire or by procedure specified by manufacturer of test equipment in use. Start engine, and run it for 2 minutes at 2000 RPM to warm Heated Oxygen Sensor (HO2S). Turn engine off, and wait 10 seconds. Activate KOER SELF-TEST using a jumper wire or appropriate procedure for test equipment used. Start engine. Record all service codes displayed. Check following items:

  • If engine starts and stalls (or stalls during self-test), go to CIRCUIT TEST S.
  • If Code 98 or 998 is displayed, EEC-IV system is operating in Failure Management Effects Mode (FMEM). PCM has detected an out-of-range sensor and has substituted a fixed value to enable vehicle to continue operation.
  • If vehicle is equipped with a Brake On-Off (BOO) switch, brake pedal must be depressed and released after ID code portion of test.
  • On vehicles with Power Steering Pressure (PSP) Switch, turn steering wheel at least 1/2 turn and release within 1-2 seconds after ID code portion of test.
  • On vehicles with Transmission Control Switch (TCS), cycle TCS switch after vehicle ID code is given.
  • If Dynamic Response Code appears, perform a brief Wide Open Throttle (WOT). DO NOT perform WOT unless requested.
  • If a Code 11 or 111 (pass code) is retrieved during KOER SELF-TEST, service Continuous Memory Codes retrieved in KOEO SELF-TEST. See SERVICE CODE REFERENCE CHARTS.
  • If a Code 11 or 111 (pass code) is retrieved during Continuous Memory Code portion of KOEO SELF-TEST and no driveability problem exists, EEC-IV testing is complete. If driveability problems are still present, go to TESTS W/O CODES article in the ENGINE PERFORMANCE Section.
  • If KOER codes are present, see SERVICE CODE REFERENCE CHARTS. If system will not output codes, go to CIRCUIT TEST QA.
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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.