Troubleshooting

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J1939 Converter Box Diagnostics

When making data source connections, there are two possible data buses available: the J1708 /J1587 low-speed data bus and the J1939 high-speed data bus. The truck year, make, and model help determine which data bus to use.

If you do not know which data source to use, contact your Qualcomm representative for assistance.

Topics in this document provide information and procedures for performing J1939 Converter Box verification:

Flowchart for J1939 Converter Box Diagnostics
Procedure for J1939 Converter Box Diagnostics

For technical questions, contact Qualcomm Enterprise ServicesSM Customer Support. Customer Support is staffed 24 hours a day, 365 days a year:

In the United States, call 800-541-7490
In Canada, call 800-863-9191

Flowchart for J1939 Converter Box Diagnostics

Flowchart for J1708/J1939 Converter Box Diagnostics

Procedure for J1939 Converter Box Diagnostics

Ignition: Third position from the left.

The steps in this procedure match the steps on the flowcharts on the previous pages. The steps are not always sequential—you may be instructed to skip steps.

  1. Turn ON ignition.
  2. Is any data missing?
    • If some data is missing, go to step 3.
    • If all data is missing, go to step 4.
Example screen.
  1. Is critical data missing, i.e., other than 6, 7, or 8?
    • If yes, call
      DSA Customer Support: 866-296-8612, or
      QESSM Customer Support:
      In the United States, call 800-541-7490
      In Canada, call 800-863-9191.
    • If no, diagnostic procedure is complete.
  1. Are power and ground present on the converter box?

    Note
    Power must come from ignition (switched +12 VDC).

    • If yes, go to step 5.
    • If no, repair power and ground connections. Perform system verification.
  1. Check that the J1939 voltage is 1–3 VDC with ignition ON (between pin C and ground, and pin D and ground) and the ohm measurement is 55–65 with ignition OFF (between pins C and D).

    Note
    There must be no data bus activity, i.e, no dash lights on when taking ohm measurement.

    Are the measurements correct?

    • If yes, go to step 6.
    • If no, repair J1939 connections. Perform system verification.
  1. Check that the converter’s J1708+ wire to ground is 3–5 VDC and the converter’s J1708- wire to ground is 0.5–2.0 VDC with ignition ON.

    Note
    J1708 must not be connected to the truck’s J1708 bus.

    Are the connections correct?

    • If yes, go to step 7.
    • If no, repair J1708 connections. Perform system verification.
  1. Are the IMCT/MCT/TMCT connectors tight?
    • If yes, go to step 8.
    • If no, tighten all connectors. Perform system verification.
Picture of the Converter Box.
  1. Test with a known, good converter box. Is the problem fixed?
    • If yes, replace the converter box. Perform system verification.
    • If no, go to step 9.
  1. Test with a known, good IMCT/MCT/TMCT accessory cable. Is the problem fixed?
    • If yes, replace the accessory cable. Perform system verification.
    • If no, go to step 10.
  1. Test with a known, good IMCT/MCT/TMCT. Is the problem fixed?
    • If yes, replace the IMCT/MCT/TMCT. Perform system verification.
    • If no call QES Customer Support:

    In the United States, call 800-541-7490
    In Canada, call 800-863-9191
    If no, perform system verification.

QUALCOMM Incorporated
5775 Morehouse Drive
San Diego, CA 92121-1714
U.S.A.

Copyright © 2009 QUALCOMM Incorporated.
All rights reserved.

QUALCOMM is a registered trademark of QUALCOMM Incorporated in the United States and may be registered in other countries.

Qualcomm Enterprise Services and QES are service marks of QUALCOMM Incorporated.

Other product and brand names may be trademarks or registered trademarks of their respective owners.

Qualcomm endeavors to ensure that the information in this document is correct and fairly stated, but Qualcomm is not liable for any errors or omissions. Published information may not be up to date, and it is important to confirm current status with Qualcomm.

This technical data may be subject to U.S. and international export, re-export or transfer (export) laws. Diversion contrary to U.S. and international law is strictly prohibited.

80-JB020-1 Rev. A
June 2009

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J1939 Converter Box Diagnostics_A.pdf179.8 KB