Note On Intermittents

If Code EO12 is stored as a history code, start engine and allow it to idle. Manipulate circuits No. 430 and 453. An intermittent open will cause the engine to stumble or stall when ECM loses distributor reference. If wiring and ECM connectors are okay, check HEI pick-up coil leads for intermittent open circuit.

Fig 1: ECM Code EO12 Circuit Diagram

Fig 2: ECM Code EO12 Flow Chart