1994 Mazda MX-3 Base, AutomaticFACTORY OEM SERVICE PROCEDURE

Powertrain Control Module

  1. Locate Electronic Control Unit (ECU) or Powertrain Control Module (PCME). See ECU/PCME LOCATION table. Connect Engine Signal Monitor (49-9200-162) to ECU/PCME. See Fig 1 . Check voltage at each terminal of ECU/PCME. If input and output component voltage readings are not as specified, check faulty component. See PIN VOLTAGE CHARTS article, appropriate G - TESTS W/ CODES article below, and testing for appropriate component in this article.
  2. If input and output component voltages are as specified and ECU/PCME voltage is incorrect, replace ECU/PCME.
CAUTION: DO NOT apply voltage to terminals "A" and "B" of engine signal monitor. See Fig 1 .
ECU/PCME LOCATION

Application Location
MX-3, Protege & 323 Behind Center Console
Fig 1: Testing Engine Control Unit (ECU)
G93D81128Courtesy of MAZDA MOTORS CORP.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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