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MCU Power & Ground Circuits

  1. Check power and ground circuits. SEE MOTRONIC CONTROL UNIT (MCU) in this article.
  2. Check that battery voltage exists from pin No. 1 of MCU to the ignition coil. If voltage does not exist, check for open or short in wiring. On models equipped with anti-theft systems, check that no voltage exists at pin No. 38 of MCU. If voltage exists, anti-theft system will prevent vehicle from starting.
NOTE: If all components are okay, engine speed/reference sensor should be checked. Sensor provides signal to MCU to provide ignition operation. See ENGINE SPEED/REFERENCE SENSOR & CIRCUIT in this article.