Operation CHARM
: Car repair manuals for everyone.
Home
>>
Pontiac
>>
1990
>>
Grand Prix V6-191 3.1L
>>
Repair and Diagnosis
>>
A L L Diagnostic Trouble Codes ( DTC )
>>
Testing and Inspection
>>
Manufacturer Code Charts
>>
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.