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Cadillac
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1991
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Seville Base
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Repair and Diagnosis
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Engine Performance
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System
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Engine Controls - Tests W/Codes
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Diagnostic Tests
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Pcm Code EO23, Est Circuit Problem (1 Of 2)
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Test Conditions (Run):
Test Conditions (Run):
By-pass line high (5 volts) and reference pulses being sent to PCM from HEI module.