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B280F With EZ115K System

  1. Turn ignition off. Remove panel from lower left of dashboard. Disconnect ECU connector from ECU. Remove cover from ECU connector. Visually inspect all pin connection sleeves to ensure all pins are at the same height.
    NOTE: When measuring resistance and voltage at connector, DO NOT probe into front of connector. Probe only through side of connector, just enough to make a good electrical contact. Pin identification is indicated on side of ECU connector.
  2. Check temperature sensor circuit using a multimeter to measure resistance. Attach multimeter lead to pin No. 2 (Green wire) of the 8 pin "F" test connector, located on left suspension tower. Attach the other lead to a good ground. If resistance is not within specifications, repeat measurement at sensor(s) to determine if sensor wire(s) or sensor(s) is defective. See TEMPERATURE SENSOR RESISTANCE  table in this article. Repair or replace as necessary.
    TEMPERATURE SENSOR RESISTANCE

    Degrees °F (°C) Resistance - Ohms
    -22 (-30) 24,000
    32 (0) 6000
    104 (40) 1200
    176 (80) 275
    248 (120) 110
  3. Check the knock sensor wire resistance with a multimeter. Disconnect the connector at fuel distribution rail. Attach a jumper wire between pin No. 1 and pin No. 2 of fuel distribution rail connector. Attach the multimeter leads between ignition ECU connector pins No. 12 and 13. See Fig 1. Resistance should be zero ohms. Check resistance between ignition ECU connector pins No. 24 and 25. Resistance should be zero ohms.
    Fig 1: Ignition ECU & Fuel Distribution Rail Connector
    G62492Courtesy of VOLVO CARS OF NORTH AMERICA.
  4. If resistance is high, an open circuit is indicated. Remove jumper wire from fuel distribution rail connector and check continuity of each wire. Repair or replace as necessary. If wiring is okay but fault code still flashes, incorrect knock sensor signal is indicated.
  5. Install a new ignition ECU and repeat test using LED Tester. If LED still flashes fault code, reinstall original ECU and install new knock sensor(s). Repeat test procedures to ensure problem is corrected.
  6. Check fuel system ECU load signal with a multimeter set for voltage measurement reading. Attach multimeter leads between ignition ECU connector pin No. 8 and ground. Turn ignition on. Voltage should be approximately 11 volts. If voltage is low or zero, there is an open circuit between the fuel ECU and ignition ECU or a defective fuel ECU.
  7. Check cylinder one position sensor using a multimeter set for ohms reading. Attach multimeter leads between ignition ECU connector pins No. 18 and 19. Resistance should be zero ohm. Check that shield wire (ground) is connected to connector pin No. 21. If not within specifications, position sensor is defective.
  8. Check throttle switch resistance with multimeter. Attach multimeter leads between ignition ECU connector pin No. 7 and ground. Resistance should be zero ohm. Slowly depress accelerator to open throttle switch. Resistance should increase. If reading is incorrect, measure resistance at throttle switch to determine if wire is broken or if throttle switch is defective.
  9. If necessary, check throttle switch adjustment. Open throttle valve slightly and listen for an audible click. The click indicates that throttle switch opens at the same time as the throttle valve. Adjust throttle switch if necessary.
  10. Check engine RPM/crankshaft position sensor resistance with a multimeter. Connect multimeter leads between ignition ECU connector pins No. 10 and 23. Resistance should be 500-600 ohms. Check that shield wire (ground) is connected to connector pin No. 11. If not within specifications, replace RPM/crankshaft position sensor.
  11. Check that test connector is not grounded using a multimeter. Connect multimeter leads between ignition ECU connector pin No. 13 and ground. Resistance should be infinity. If not within specifications, test connector is either damaged or grounded. The test connector is a one wire (Yellow with Red) connector located at the right front fender in the engine compartment by the air cleaner assembly.
  12. Connect multimeter leads between ignition ECU connector pin No. 20 and ground. Resistance should be zero ohm. If not within specifications, repair open circuit.
  13. Turn ignition off and reconnect ignition ECU connector. Remove air cleaner assembly to gain access to power stage connector. Disconnect power stage connector and remove connector dust cover. Check ignition coil primary winding resistance with a multimeter.
  14. Connect multimeter leads between power stage connector pin No. 1 and No. 4. Resistance should be 0.6-1.0 ohm. If resistance is below 0.6 ohm, check wires for short circuit. If wires are okay and resistance is still below 0.6 ohm or above 1.0 ohm, proceed to next step.
  15. Connect multimeter leads between ignition coil terminals. If resistance is below 0.6 ohm or above 1.0 ohm install a new ignition coil and recheck resistance. If resistance is correct, check continuity of wires between ignition coil and connector pins No. 1 and 4. Repair or replace wire as necessary.
  16. Attach multimeter leads between terminal No. 1 of ignition coil and coil tower. See Figure. Resistance should be 6500-9000 ohms. If not within specifications, replace ignition coil.
  17. Check power stage ground resistance with a multimeter. Attach multimeter leads between power stage connector pin No. 2 and ground. Resistance should be zero ohm. Check shield wire between ignition ECU and power stage. Shield wire should be connected to pin No. 3 of power stage connector.
  18. Check for voltage at ignition coil and power stage with a multimeter. Connect multimeter negative (-) lead to ground. Connect multimeter positive (+) lead to power stage connector pin No. 4. Turn ignition on and note voltage reading. Voltage should be approximately 12 volts. Proceed to next step.
  19. Crank starter motor and observe voltage reading. Voltage should be at least 10.5 volts. If voltage is too low, check battery and charging system. If there is no voltage, check wires between ignition ECU, ignition coil and power stage. Repair or replace as necessary.
  20. Turn ignition off. If no defects were found in the previous steps and problems still exists, install a new ignition ECU and/or power stage. Reconnect disconnected components and recheck system.
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