No Communication with Electronic Brake Control Module/Electronic Brake and Traction Control Module. Pontiac Firebird 1998

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 1998 🢒 Firebird 🢒 Brakes 🢒 Antilock Brake System 🢒 No Communication with Electronic Brake Control Module/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

•	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 Troubleshooting Procedures Cell 4 in Electrical Diagnosis.

No Communication with EBCM/EBTCM

Step	Action	Value(s)	Yes	No
DEFINITION: Scan tool can not communicate with the EBCM/EBTCM.
1	Was the Diagnostic System Check performed?	--	Go to Step 2	Go to Diagnostic System Check
2	Turn the Ignition switch to the RUN 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 Data Link Connector Cell 50 in Electrical Diagnosis
3	Inspect the 10A ABS IGN fuse in the Underhood Electrical Center 2. Is the fuse OK?	--	Go to Step 4	Go to Step 6
4	Install the fuses if removed. Turn the ignition switch to the RUN position, engine off. Using J 39200 DMM, measure the voltage at the 10A ABS IGN fuse 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 Cell 10 in Electrical Diagnosis
5	Turn the ignition switch to the OFF position. Disconnect the EBCM/EBTCM connector C1. Connect the J 39700 Universal Pinout Box using the J 39700-25 to the EBCM/EBTCM harness connector C1 only. Using J 39200 DMM, measure the resistance between J 39700 terminal 15 and a good ground. Is the resistance within the range specified in the value(s) column?	0 - 2ohms	Go to Step 10	Go to Step 9
6	Install a new 10A ABS IGN fuse. Cycle the ignition switch from the OFF to RUN position, engine off. Recheck the fuse. Is the fuse OK?	--	Go to Diagnostic System Check	Go to Step 7
7	Turn the ignition switch to the OFF position. Remove the 10A ABS IGN fuse. Disconnect the EBCM/EBTCM connector C1. Connect the J 39700 Universal Pinout Box using the J 39700-25 to the EBCM/EBTCM harness connector C1 only. Using J 39200 DMM, measure the resistance between terminals 8 and 15 of J 39700 . 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 739 for a short to ground. Refer to Repair Procedures Cell 5 in Electrical Diagnosis. Is the repair complete?	--	Go to Diagnostic System Check	--
9	Repair CKT 651 or G101 for an open or high resistance. Refer to Repair Procedures Cell 5 in Electrical Diagnosis. Is the repair complete?	--	Go to Diagnostic System Check	--
10	Turn the ignition switch to the RUN position, engine off. Using J 39200 DMM, measure the voltage between J 39700 terminals 8 and 15. Is the voltage within the range specified in the value(s) column?	Battery Volts	13	Go to Step 11
11	Repair CKT 739 for an open. Refer to Repair Procedures Cell 5 in Electrical Diagnosis. Is the repair complete?	--	Go to Diagnostic System Check	--
12	Replace the EBCM/EBTCM. Refer to Electronic Brake Control Module Replacement . Is the replacement complete?	--	Go to Diagnostic System Check	--
13	Turn the ignition switch to the OFF position. Using J 39200 DMM, measure the resistance between the J 39700 terminal 24 and the DLC terminal 9. Is the resistance within the range specified i the values column?	0-2ohms	Go to Step 12	Go to Step 14
14	Repair CKT 800 for an open or high resistance. Refer to Repair Procedures Cell 5 in Electrical Diagnosis. Is the repair complete?	--	Go to Diagnostic System Check	--