No Communication with Electronic Brake Control Module. Chevrolet Monte Carlo 1999

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 1999 🢒 Monte Carlo 🢒 Brakes 🢒 Antilock Brake System 🢒 No Communication with Electronic Brake Control Module

ABS Components
Antilock Brake System Schematics

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 General Electrical Diagnosis in wiring systems.

No Communication with EBCM

Step	Action	Value(s)	Yes	No
DEFINITION: Scan tool can not communicate with the EBCM.
1	Was the 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. Connect a scan tool, 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 Communications System Check
3	Turn the ignition switch to the OFF position. Disconnect the EBCM connector C1. Using J 39200 DMM, measure the resistance between connector C1 terminal A1 and the DLC (Data Link Connector) terminal 9. Is the resistance within the range specified in the values column?	0.2 - 5 ohms	Go to Step 5	Go to Step 4
4	Repair CKT 800 for an open or high resistance. Refer to General Electrical Diagnosis in wiring systems. Is the repair complete?	--	Diagnostic System Check - ABS	--
5	Turn the ignition switch to the OFF position. Inspect the Fuse 13 located in Fuse Block Disconnect the EBCM connector C1. Turn the ignition switch to the ON position, engine off. Using J 39200 DMM, measure the voltage between connector C1 terminal A9 and a good ground. Is the voltage within the range specified within the values column?	Battery Voltage	Go to Step 7	Go to Step 6
6	Repair CKT 341 for a short to ground or open. Refer to Wiring Repairs in wiring systems Is the repair complete?	--	Go to Step 7	--
7	Turn the ignition switch to the OFF position. Reconnect C1 to EBCM. Disconnect the EBCM C2. Using J 39200 DMM, measure the resistance between connector C2 terminal D and a good ground. Is the resistance within the range specified within the values column?	0.2-10 ohms	Go to Step 8	Go to Wiring Repairs in Wiring Systems
8	Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Is the repair complete?	--	Diagnostic System Check - ABS	--