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HOMESERVICE MANUALSMAZDA1999PROTEGE ES, AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMENGINE CONTROLS - SYSTEM & COMPONENT TESTINGCOMPUTERIZED ENGINE CONTROLSPOWERTRAIN CONTROL MODULE (PCM)POWER CIRCUIT CHECKS
1999 Mazda Protege ES, Automatic

Power Circuit Checks

1999 Mazda Protege ES, AutomaticSECTION Power Circuit Checks
  1. Using a voltmeter, check for battery voltage between PCM constant battery power terminals and ground. See appropriate wiring diagram in WIRING DIAGRAMS article to determine PCM power terminals. See PCM LOCATIONS  table. If battery voltage is not present, check PCM power supply fuse. If fuse is okay, check for open in power supply or PCM wiring.
  2. Turn ignition on. Using a voltmeter, check for battery voltage between PCM ignition power terminals and ground. If battery voltage is not present, check power supply fuse(s). If fuse is okay, check for an open in wiring between fuse and PCM, or check for a defective ignition switch.
  3. Connect voltmeter between ground and PCM start (crank) signal terminal. Turn ignition switch to START position. Battery voltage should be present between PCM start terminal and ground only when ignition switch is in START position. If voltage is not present, check fuse(s). If fuse is okay, check for open circuit in wiring harness between fuse and PCM. If wiring harness is okay, check for a defective ignition switch.
PCM LOCATIONS

Application Location
Miata Below Center Of Instrument Panel
Millenia Below Center Of Instrument Panel
Protege Below Center Of Instrument Panel
626 Below Front Of Center Console
RENDER: 1.0x

NO RELATED

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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.