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Home >> Mazda >> 2002 >> Tribute LX, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 60 (Engine Controls [Self-Diagnostics 2.3L]) >> Diagnostic Tests >> DTC U0073, U1900 Or U2516 >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
  1. Determining Location Of A Malfunction -  Determine malfunctioning part of CAN system. See PROCEDURES FOR DETERMINING LOCATION OF A MALFUNCTION  under SYSTEM TESTS. See Fig 1. If malfunction is not part of wire harness "E" or instrument cluster, go to next step. If malfunction is part of wire harness "E" or instrument cluster, go to step  6.
    Fig 1: CAN System Wiring Diagram
    G00221530Courtesy of MAZDA MOTORS CORP.
  2. Determining Location Of A Malfunction -  If malfunction is not part of wire harness "D" or ABS/TCS HU/CM, go to next step. If malfunction is part of wire harness "D" or ABS/TCS HU/CM, go to step  12.
  3. Determining Location Of A Malfunction -  If malfunction is not part of wire harness "C", go to next step. If malfunction is part of wire harness "C", go to step  14.
  4. Determining Location Of A Malfunction -  If malfunction is not part of wire harness "B" or TCM, go to next step. If malfunction is part of wire harness "B" or TCM, go to step  17
  5. Determining Location Of A Malfunction -  If malfunction is not part of wire harness "A" or PCM, trouble shooting is completed. If malfunction is part of wire harness "A" or PCM, go to step  19.
  6. Inspect Instrument Cluster Connector - 
    • Disconnect negative battery cable
    • Disconnect instrument cluster harness connector
    If instrument cluster harness connector is okay, go to next step. If instrument cluster harness connector is faulty, replace wire harness.
  7. If vehicle is equipped with ABS/TCS, go to next step. If vehicle is not equipped with ABS/TCS, go to step  9.
  8. Inspect Wire Harness Between ABS/TCS HU/CM & Instrument Cluster -  Disconnect ABS/TCS HU/CM harness connector. Inspect following wire harness between ABS/TCS HU/CM and instrument cluster harness connector terminals for short to ground, short to power supply, and open circuit:
    • "R" - "2W" (CAN_L)
    • "O" - "2X" (CAN_H)
    If wire harness is okay, replace instrument cluster. After repair, go to step  21. If wire harness is faulty, replace wire harness.
  9. If inspected vehicle has a automatic transaxle, go to next step. If inspected vehicle has a manual transaxle, go to step  11.
  10. Inspect wire Harness Between TCM & Instrument Cluster -  Disconnect TCM harness connector. Inspect following wire harness between TCM and instrument cluster harness connector terminals for short to ground, short to power supply, and open circuit:

    FN4A-EL

    • "2X" - "2W" (CAN_L)
    • "2W" - "2X" (CAN_H)
    If wire harness is okay, replace instrument cluster. After repair, go to step  21. If wire harness is faulty, replace wire harness.
  11. Inspect wire Harness Between PCM & Instrument Cluster -  Disconnect PCM harness connector. Inspect following wire harness between PCM and instrument cluster harness connector terminals for short to ground, short to power supply, and open circuit:
    • "2R" - "2W" (CAN_L)
    • "2U" - "2X" (CAN_H)
    If wire harness is okay, replace instrument cluster. After repair, go to step  21. If wire harness is faulty, replace wire harness.
  12. Inspect ABS/TCS HU/CM Connector -  Disconnect negative battery cable. Disconnect ABS/TCS HU/CM harness connector. If ABS/TCS HU/CM harness connector is okay, go to next step. If ABS/TCS HU/CM harness connector is faulty, replace wire harness.
  13. Inspect Wire Harness Between ABS/TCS HU/CM & Instrument Cluster -  Disconnect instrument cluster harness connector. Inspect following wire harness between ABS/TCS HU/CM and instrument cluster harness connector terminals for short to ground, short to power supply, and open circuit:
    • "R" - "2W" (CAN_L)
    • "O" - "2X" (CAN_H)
    If wire harness is okay, replace ABS/TCS HU/CM. After repair, go to step  21. If wire harness is faulty, replace wire harness.
  14. If inspected vehicle has a automatic transaxle, go to next step. If inspected vehicle has a manual transaxle, go to step  16.
  15. Inspect Wire Harness Between TCM & ABS/TCS HU/CM -  Disconnect negative battery cable. Disconnect TCM harness connector. Disconnect ABS/TCS HU/CM harness connector. Inspect following wire harness between TCM and ABS/TCS HU/CM harness connector terminals for short to ground, short to power supply, and open circuit:

    FN4A-EL

    • "2X" - "K" (CAN_L)
    • "2W" - "O" (CAN_H)
    If wire harness is okay, go to step  21. If wire harness is faulty, replace wire harness.
  16. Inspect Wire Harness Between PCM & ABS/TCS HU/CM -  Disconnect negative battery cable. Disconnect PCM connector. Disconnect ABS/TCS HU/CM harness connector. Inspect following wire harness between PCM and ABS/TCS HU/CM harness connector terminals for short to ground, short to power supply, and open circuit:
    • "2R" - "K" (CAN_L)
    • "2U" - "O" (CAN_H)
    If wire harness is okay, go to step  21. If wire harness is faulty, replace wire harness.
  17. Inspect TCM Connector - 
    • Disconnect negative battery cable
    • Disconnect TCM harness connector
    If TCM harness connector is okay, go to next step. If TCM harness connector is faulty, replace wire harness.
  18. Inspect Wire Harness Between TCM & Instrument Cluster -  Disconnect instrument cluster harness connector. Inspect following wire harness between TCM and instrument cluster harness connector terminals for short to ground, short to power supply, and open circuit:

    FN4A-EL

    • "2X" - "2W" (CAN_L)
    • "2W" - "2X" (CAN_H)
    If wire harness is okay, replace TCM. After repair, go to step  21. If wire harness is faulty, replace wire harness.
  19. Inspect PCM Connector - 
    • Disconnect negative battery cable.
    • Disconnect PCM harness connector.
    If PCM harness connector is okay, go to next step. If PCM harness connector is faulty, replace wire harness.
  20. Inspect Wire Harness Between PCM & Instrument Cluster -  Disconnect instrument cluster harness connector. Inspect following wire harness between PCM and instrument cluster harness connector terminals for short to ground, short to power supply, and open circuit:
    • "2R" - "2W" (CAN_L)
    • "2U" - "2X" (CAN_H)
    If wire harness is okay, replace PCM. After repair, go to next step. If wire harness is faulty, replace wire harness.
  21. Check DTC Indicated - 
    • Connect PCM connector
    • Connect TCM connector
    • Connect ABS/TCS HU/CM connector
    • Connect instrument cluster connector
    • Clear DTC from module memory using scan tool
    • Perform KOEO/KOER self-test
    If DTCs U0073, U1900 and/or U2516 are indicated, repeat step  1. If DTCs U0073, U1900 and/or U2516 are not indicated, trouble shooting is completed.
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