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Home >> Chevrolet >> 1995 >> Corvette Base, 2D Convertible, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> ECM/Pcm Code Charts >> Code 91, 1-4 Upshift Light >> Test Description
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Test Description

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. The 1-4 upshift light should not turn on. If light is on, circuit is shorted to ground or PCM is faulty.
  2. PCM should turn on 1-4 upshift light.
  3. Checks 1-4 upshift light circuit up to PCM connector. If light illuminates, PCM connector is faulty or PCM does not have ability to ground circuit.
Fig 1: Code 91 Schematic (Corvette) 1-4 Upshift Light
G95F14378
Fig 2: Code 91 Diagnostic Flow Chart (Corvette) 1-4 Upshift Light
G94I35178
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