LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Volvo >> 1992 >> 940 GL, AW70L >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Self-Diagnostics - Fuel Injection >> Control Function No. 2 >> Activating Circuit Breakers
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Activating Circuit Breakers

  1. Turn ignition on. Locate diagnostic unit, and remove its cover. Connect selector cable to socket No. 2. Turn throttle control at throttle body to full-load position. Depress push button twice. Each time button is depressed, hold it for more than one second and less than 3 seconds. Red LED should flash.
  2. Release throttle control. If flash series 3-3-3 comes up, throttle switch works correctly in full-load position. If LED continues to flash rapidly, check throttle switch setting. See procedures in ADJUSTMENTS article in the ENGINE PERFORMANCE Section, and go to next step.
  3. Connect an ohmmeter between terminal No. 3 (Yellow/White wire on 240; Orange wire on 740/940) of fuel system ECU and ground. Resistance should be infinite with throttle switch closed. Depress gas pedal slightly. Resistance should be zero ohms. If resistance is not as specified, check wiring from ECU to throttle switch.
  4. Turn throttle control slightly, and observe Red LED. If LED turns off and then flashes 3-3-2 code, throttle switch is working properly in idle position. If LED does not flash as described, repeat step 3).
  5. Start engine, and check RPM signal from ignition system ECU to fuel system ECU. If LED turns off and then flashes 3-3-1 code, RPM signal is correct. If engine will not start, run starter until LED turns off and go to next step. If LED continues to flash, check ignition system and see DIAGNOSTIC UNIT LED DOES NOT FLASH.
    NOTE: Steps 6-9 are for A/C-equipped models and steps 10-11 are for A/T-equipped models.
  6. Check on/off function of A/C compressor. Put A/C control in ON position. If LED continues to flash, go to next step. If LED turns off and then flashes 1-1-4 code, A/C switch is okay. Go to step 8).
  7. Connect ohmmeter between terminal No. 15 (Gray/Red wire on 240; Green/Yellow wire on 740/940) of fuel system ECU and ground. On 240, resistance should be 1000 ohms with A/C off and 10 ohms with A/C on. On 740/940, resistance should be infinity with A/C off and 35 ohms with A/C on. If resistance is not as specified, check wiring and connections.
  8. Turn ignition off. LED should flash rapidly before A/C compressor turns on. When compressor turns on, LED should turn off and then flash 1-3-4. If LED continues to flash, go to next step.
  9. Connect an ohmmeter between terminal No. 15 of fuel system ECU and ground. Resistance should be 35 ohms with A/C on. If resistance is not as specified, check wiring and connections.
  10. This step will test idle speed compensation on A/T-equipped models. Depress brake pedal, and place gear selector in DRIVE and then NEUTRAL position. Observe LED while shifting. A code 1-2-4 should flash, indicating test is complete. If LED continues to flash rapidly, go to next step.
  11. Put transmission gear selector in NEUTRAL position. Connect an ohmmeter between terminal No. 30 (Blue/Yellow wire on 240; Pink wire on 740/940) of fuel system ECU and ground. Resistance should be zero ohms with selector in NEUTRAL position and infinity with selector in DRIVE position. If resistance is not as specified, check wiring, connections and gear selector switch.
scientia non olet · About LEMON Manuals