GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2000 🢒 Grand Prix 🢒 Brakes 🢒 Antilock Brake System 🢒 No Communication with Electronic Brake and Traction Control Module

Circuit Description

The UART serial data link allows information to be exchanged from module to module as needed. This is done by the PCM, the PCM requests and sends all the information that is transmitted on the UART line. When a scan tool is connected to the UART line it takes over for the PCM and sends and requests the needed information.

Diagnostic Aids
    • It is very important to start with the ABS Diagnostic System Check before performing the No Communications with EBCM diagnosis. The ABS Diagnostic System Check will direct you to the Data Link Communications Diagnostic System Check in Data Link Communications to diagnose a malfunction that effects the entire serial data circuit. The No Communications with EBCM diagnostic table will diagnose a malfunction with the power or ground circuits and the UART circuit to the EBCM only. For diagnosis of the entire UART serial data circuit, refer to Data Link Communications System Check in Data Link Communications.
    • Thoroughly inspect the wiring and the connectors. Failure to carefully and fully inspect the wiring and the connectors can result in misdiagnosis. Misdiagnosis may cause replacement of parts without repairing the malfunction.
    • If an intermittent malfunction exists, refer to General Electrical Diagnosis in Wiring Systems.

No Communication with EBTCM

Step

Action

Value(s)

Yes

No

DEFINITION: Scan tool can not communicate with the EBTCM.

Schematic Reference: Data Link Connector Schematics in Data Link Communications.

1

Was the ABS Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

Turn the Ignition switch to the ON position with the engine off.

Can the scan tool communicate with other modules on the UART serial data line, such as the PCM?

--

Go to Step 3

Go to Scan Tool Does Not Communicate with UART Data Line in Data Link Communications

3

Inspect the 10A Trans / ABS fuse 26 in the Underhood Accessory Wiring Junction Block.

Is the fuse OK?

--

Go to Step 4

Go to Step 6

4
  1. Install the fuse if removed.
  2. Turn the ignition switch to the ON position, engine off.
  3. Using the DMM, measure the voltage at the 10A Trans / ABS fuse 26 by probing between the fuse test terminals and a good ground.

Is the voltage within the range specified within the value(s) column?

Battery Volts

Go to Step 5

Go to Power Distribution Schematics in Wiring Systems

5
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the EBCM connector C1.
  3. Connect the Universal Pinout Box using the J 39700-530 cable adapter to the EBCM harness connector C1 only.
  4. Using the DMM, measure the resistance between the Universal Pinout Box terminal 15 and a good ground.

Is the resistance within the range specified in the value(s) column?

0 - 5ohms

Go to Step 10

Go to Step 9

6
  1. Install a new 10A Trans / ABS fuse 26.
  2. Turn the ignition switch from the OFF to ON position, engine off.
  3. Recheck the fuse.

Is the fuse OK?

--

Go to Diagnostic System Check - ABS

Go to Step 7

7
  1. Turn the ignition switch to the OFF position.
  2. Remove the 10A Trans / ABS fuse 26.
  3. Disconnect the EBCM connector C1.
  4. Connect the Universal Pinout Box using the J 39700-530 cable adapter to the EBCM harness connector C1 only.
  5. Using the DMM, measure the resistance between terminals 8 and 15 of the Universal Pinout Box .

Is the resistance within the range specified in the value(s) column?

OL (infinite)

Go to Step 12

Go to Step 8

8

Repair CKT 1039 for a short to ground. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

9

Repair CKT 251 or G201 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

10
  1. Turn the ignition switch to the ON position, engine off.
  2. Using the DMM, measure the voltage between the Universal Pinout Box terminals 8 and 15.

Is the voltage within the range specified in the value(s) column?

Battery Volts

Go to Step 13

Go to Step 11

11

Repair CKT 1039 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

12

Replace the EBCM. Refer to Electronic Brake and Traction Control Module Replacement .

Is the replacement complete?

--

Go to Diagnostic System Check - ABS

--

13
  1. Turn the ignition switch to the OFF position.
  2. Remove the bus bar from the Splice Pack SP 205.
  3. Using the DMM, measure the resistance between the Universal Pinout Box terminal 25 and the Splice Pack terminal E.

Is the resistance within the range specified in the values column?

0-5ohms

Go to Step 12

Go to Step 14

14

Repair CKT 1122 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--