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Home >> Mitsubishi >> 1993 >> Precis Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Tests >> Code 42: Fuel Pump Failure >> Harness Inspection
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Harness Inspection

  1. Using a jumper wire, apply battery voltage to fuel pump check terminal. See BASIC TESTING article in this section for fuel pump check terminal location. If fuel pump does not operate, go to step 2. If fuel pump operates, go to step 4.
  2. Disconnect fuel pump connector. Using DVOM, check continuity between chassis ground and fuel pump connector terminal No. 2 (Black wire). If continuity does not exist, inspect and repair circuit as needed.
  3. Check continuity between fuel pump harness connector terminal No. 1 (Yellow wire) and fuel pump checking terminal. If continuity does not exist, inspect and repair circuit as needed.
  4. Ensure ignition is off. Disconnect ECM control relay and ECM harness connectors. Move jumper wire connected to fuel pump checking terminal to vehicle ground. Using ohmmeter, check resistance between ECM control relay harness connector terminal and vehicle ground. See ECM CONTROL RELAY TERMINAL ID  table. If continuity does not exist, inspect and repair circuit as needed.
    ECM CONTROL RELAY TERMINAL ID

    Application Relay Terminal No. Wire Color Corresponding ECM Terminal No.
    California 4 Yellow (1) N/A
    Federal 4 Yellow (2) 7
    (1) 24-pin connector.
    (2) 10-pin connector.
  5. Check resistance between ECM harness connector terminal and vehicle ground. See ECM CONTROL RELAY TERMINAL ID  table. See Figure and Figure . If continuity does not exist, inspect and repair circuit as needed.
  6. Turn ignition on. Using DVOM, measure voltage between ECM control relay harness connector terminal and vehicle ground. See ECM POWER SUPPLY TERMINAL ID  table. Voltage should be 8 volts or more. Turn ignition switch to START position. Measure voltage between ECM control relay connector terminal and vehicle ground. See ECM POWER SUPPLY TERMINAL ID  table. Voltage should be 8 volts or more. If voltage is not within specification, inspect and repair circuit(s) as needed.
    ECM POWER SUPPLY TERMINAL ID

    Application (1) Terminal No. Wire Color
    Ignition Switch
    ON Position 1 White/Blue
    START Position 6 (2) Black/Green
    (1) See Figure and Figure .
    (2) Black/Yellow wire on manual transmission models.
  7. Connect jumper wire between ECM harness connector terminal and vehicle ground. See ECM FUEL PUMP SIGNAL TERMINAL ID  table. Measure resistance between ECM control relay connector terminal and vehicle ground. See ECM FUEL PUMP SIGNAL TERMINAL ID  table. If continuity does not exist, inspect and repair circuit as needed.
  8. Using ohmmeter, check resistance between chassis ground and ECM control relay harness connector terminal No. 7 (Black wire). If continuity does not exist, inspect and repair circuit as needed.
    ECM FUEL PUMP SIGNAL TERMINAL ID

    Application ECM Terminal No. Wire Color Relay Terminal No.
    California (2) 6 White/Red 8
    Federal (1) 4 White/Red 8
    (1) 18-pin connector.
    (2) 26-pin connector.
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