Engine Control System (Diagnostics) (H4DO): General Description: Caution

2014 Subaru Forester 2.5i, Eng CD FB25BA, Standard TransSECTION Caution
  1. Airbag system wiring harness is routed near the ECM, main relay and fuel pump relay.
    CAUTION:
    • Do not use electrical test equipment on the airbag system circuits.
    • Be careful not to damage the airbag system wiring harness when servicing the ECM, TCM, main relay and fuel pump relay.
  2. Never connect the battery in reverse polarity. Doing so will damage the ECM instantly, and other parts will also be damaged.
  3. Do not disconnect the battery terminals while the engine is running. A large counter electromotive force will be generated in the generator, and this voltage may damage electronic parts such as ECM etc.
  4. When disconnecting the connectors of the electrical components, always be sure to turn the ignition switch to OFF. Perform the Clear Memory Mode after connecting the connectors. < Ref. to CLEAR MEMORY MODEΒ . >
  5. When measuring the voltage or resistance of individual sensor or all electrical control modules, use a tapered pin with a diameter of less than 0.6 mm (0.024 in). Do not insert the pin 4 mm (0.16 in) or more into the part.
    CAUTION: When replacing the ECM, be careful not to use the ECM of wrong specification to avoid any damage on the fuel injection system.
RENDER: 1.0x

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When to See a Mechanic

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

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