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Home >> Geo >> 1993 >> Prizm Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> DIAGNOSTIC CODE CHARTS (EXCEPT LSi) >> Code 12, No Rpm Signal >> Diagnostic Aids
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Diagnostic Aids

Check for cracks in distributor cap and rotor. Check for properly adjusted signal rotor air gap.

An intermittent condition may be caused by poor connection, rubbed-through insulation, or a broken wire inside insulation. Check ECM harness connectors for backed-out, improperly mated, broken locks, improperly formed, or damaged terminals, and poor terminal-to-wire connections before component replacement.

Fig 1: Code 12 Schematic (Except LSi) No RPM Signal
G93G78812
Fig 2: Code 12 Flow Chart (Except LSi) No RPM Signal
G93H78813