LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Geo >> 1994 >> Metro XFi >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Computerized Engine Controls >> Engine Control Module (ECM) >> Power Circuit Checks
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Power Circuit Checks

  1. Using a voltmeter, check for battery voltage between ECM constant battery power terminals and ground. See appropriate wiring diagram in WIRING DIAGRAMS article in this section to determine ECM power terminals. If battery voltage is not present, check ECM power supply fuse. If fuse is okay, check for open in power supply or ECM wiring.
  2. Turn ignition switch to ON position. Using a voltmeter, check for battery voltage between ECM 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 ECM, or check for a defective ignition switch.
  3. Connect voltmeter between ground and ECM start (crank) signal terminal. Turn ignition switch to the START position. Battery voltage should be present between ECM 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 an open in wiring between fuse and ECM, or check for a defective ignition switch.
scientia non olet · About LEMON Manuals