EEC IV - Code 18 Misdiagnosis

88ford13

Article No. 88-12-14

EEC IV QUICK TEST - 5.0L SEFI - SERVICE CODE "18" - MISDIAGNOSIS ON VEHICLES BUILT 2/16/87 TO 6/01/87

LINCOLN-MERCURY: 1988 LINCOLN TOWN CAR

This article is being republished to expand the vehicle build date range and correct the model year application.


ISSUE: The EEC IV service code "18" may be in error "KEY ON/ENGINE RUNNING" (KOER) self-test. The service code "18" is characteristic for this EEC IV calibration.

ACTION: To prevent misdiagnosis of service code "18", use the following diagnostic procedure.

NOTE: "KOER" SERVICE CODE "18" SHOULD NOT BE CONFUSED WITH "KEY ON/ENGINE OFF" (KOEO) SERVICE CODE "18".

1. If service code "18" is displayed "KOER" self-test, check the engine ignition timing with a timing light.

2. If the ignition timing changes when the throttle is moved (WITH THE SPOUT CONNECTED), then service code "18" is in error and should be ignored.

3. If the timing does not change when the throttle is moved, then service code "18" is correct. Refer to the 1987 Engine/Emissions Diagnosis Manual Supplement, Volume H for additional diagnostic assistance.

OTHER APPLICABLE ARTICLES: Supersedes 87-5-25
WARRANTY STATUS: "INFORMATION ONLY"