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Home › Chevrolet › 1998 › Forward Control P12 › Repair and Diagnosis › External Pages › Different variant/trim › Section 13 (Instrument Panel - Commercial Van) › System Tests › Service Engine Soon Indicator Always On

Service Engine Soon Indicator Always On

WARNING: This page is about a different variant/trim than selected.
  1. Disconnect Powertrain Control Module (PCM) or Vehicle Control Module (VCM) harness connectors. Turn ignition switch to RUN position. If indicator goes out, problem is in PCM or VCM. See TESTS W/CODES article in ENGINE PERFORMANCE section. If indicator remains lit, go to next step.
  2. Using test light, backprobe instrument cluster harness connector terminal No. 23 (Brown/White wire) to battery power. If test light lights, repair short to ground in Brown/White wire. If test light does not light, repair and/or replace instrument cluster.
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