Genuine Volvo 740 Engine Control Module

Volvo 740 Engine Control Module Parts and Q&A

• Ignition Module
  3517369
  Q: What functions does the Engine Control Module (ECM) perform and how is it installed on Volvo 740?

  A:

  The Engine Control Module (ECM) performs numerous functions by accepting information from various engine sensors to compute the necessary fuel flow rate for maintaining the correct air/fuel ratio across the engine's operational range. It generates output signals to control relays, actuators, and solenoids, and commands the fuel injectors to meter the appropriate amount of fuel, while automatically compensating for altitude changes during driving. If the battery cable is disconnected for over 5 minutes, the adaptive fuel factor will be lost, requiring a driving period of at least 10 miles, potentially up to 250 miles, to allow the processor to relearn the correct factors, which may initially cause driveability symptoms that will clear as corrections are computed. For the Coupe, 240, 700, and 940 Series, the ECM is located under the passenger side footwell; the process involves disconnecting the negative battery cable, removing the kickpanel, unfastening the ECM bracket bolts, lowering the ECM, unlatching the harness connector, and removing the ECM, followed by reinstallation steps. In the 960/S90/V90 Series, the ECM is found behind the driver's side dash panel beneath the steering column, requiring similar disconnection and removal steps. For the 850/C70/S70/V70 Series, the ECM is located in the engine compartment within a box similar to the air cleaner box, where it may be accompanied by other modules; the procedure includes disconnecting the negative battery cable, removing the module box lid, unsnapping the harness connector, and removing the ECM, followed by reinstallation steps. After installation in all models, it is essential to start the vehicle and ensure the "check engine" light on the instrument cluster is functioning.