GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2001 🢒 Isuzu T-Series (Truck Line C) 🢒 Body and Accessories 🢒 Data Link Communications 🢒 Scan Tool Does Not Communicate with Electronic Brake Control Module

Test Description (JE3 option only)

This test can also be referred to as "Scan Tool Does Not Communicate with UART data line".

  1. A module which loses power during an ignition cycle will cause other module(s) to set Lost Communication DTCs.

  1. A module which loses power during an ignition cycle will cause other module(s) to set Lost Communication DTCs.

  1. The module which was not communicating due to an open in the serial data circuit may have set Lost Communication DTCs for those modules that it was monitoring.

  1. The modules which can communicate indicate the module which cannot communicate. You must clear the DTC from these modules to avoid future misdiagnosis.

Step

Action

Yes

No

Refer to Data Link Connector Schematics

1

Test the battery positive (B+) voltage circuit(s) and the ignition voltage circuit(s) of the EBCM (electronic brake control module) for an open or a short to ground. Refer to Circuit Testing and in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 2

2

Test the ground circuit(s) of the module that is not communicating for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 8

Go to Step 3

3

Test the UART serial data circuit of the EBCM for an open between the DLC and the EBCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 6

Go to Step 4

4

Inspect for poor connections/terminal tension at the battery positive voltage circuit(s), the ignition voltage circuit(s), the ground circuit(s), and the serial data circuit of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 6

Go to Step 4

5

Replace the EBCM . Refer to Electronic Brake Control Module Replacement for the appropriate Repair Instructions.

Did you complete the replacement?

Go to Step 8

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6

  1. Install a scan tool.
  2. Turn ON the ignition leaving the engine OFF.
  3. Select the Display DTCs function for the EBCM.

Does the scan tool display any DTCs which do not begin with a U?

Go to the applicable Diagnostic System Check

Go to Step 7

7

Use the scan tool in order to clear the DTCs

Did you clear all DTCs?

Go to Step 8

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8

Select the Display DTCs function for the module(s) which had the Lost Communications with XXX DTC set.

Does the scan tool display any DTCs which do not begin with a U?

Go to the applicable Diagnostic System Check

Go to Step 9

9
  1. Use the scan tool in order to clear the DTCs
  2. Continue diagnosing or clearing the DTCs until all the modules have been diagnosed and all the DTCs have been cleared.

Did you complete the action?

System OK

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