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Oldsmobile
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1991
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Cutlass Supreme FWD V6-189 3.1L
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Repair and Diagnosis
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A L L Diagnostic Trouble Codes ( DTC )
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Testing and Inspection
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Manufacturer Code Charts
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DTC 55
DTC 55
CODE 55
Be sure ECM grounds are OK and that the MEM-CAL is properly latched. If OK, replace electronic control module ECM.
Clear Codes and confirm "Closed Loop" Operation and No "SERVICE ENGINE SOON" Light.