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Home >> Buick >> 1980 >> Skyhawk Base, Automatic Trans >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Computer Controlled Catalytic Converter System C-4 >> Testing & Diagnosis >> Diagnostic Memory
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Diagnostic Memory

C-4 system is designed with a short-term memory. It will store a trouble code as long as the ignition switch is on. When it is turned off, the memory will be erased. To remember intermittent problems, and because some trouble codes do not register for 5-18 minutes after engine warmup, a long-term memory is sometimes needed. To create a long-term memory, connect the orange terminal lead "S" ("R" on 3.8L V6) of the ECM to fuse block cavity marked "GAUGES".

NOTE: Some 1980 vehicles are equipped with a full-time long term memory. To erase memory on these, after repairs are completed, disconnect ECM terminal "S" ("R" on 3.8L V6) and reconnect to briefly interrupt power supply to memory.
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