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molurch, GMC Mechanic
Category: GM
Satisfied Customers: 20444
Experience:  GM, Chevrolet Cert., Heavy Line Mech, Race Shop Owner, Mobile Electronics.
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2005 GMC: van..floor and that the abs and brake light came on

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Hello I have a 2005 GMC Savana G3500 series van. Customer claims that brake pedal went to floor and that the abs and brake light came on. I have truck in shop and everything seems fine brake pedal is high, truck stops well, no lights. I did pull code C0201 out of history and was wondering if anyone has seen this before.


C0201 is for Antilock Brake System (ABS) Enable Relay Contact Circuit
I would suspect if the circuit failed or the Relay locked, it could cause a problem as you describe, but not loss of Brakes, just a feeling of the ABS going out & harder Pedal





Customer: replied 6 years ago.
what typically casuses this?



The system relay, located within the electronic brake control module (EBCM), supplies battery voltage to all of the valve solenoids and to the precharge pump motor. When the relay contacts close, the EBCM monitors the voltage supplied to the valve solenoids and compares this voltage to monitored ignition voltage.


Cause could be:


The EBCM detects that the voltage supplied to the valve solenoids is less than 65 percent of the monitored ignition voltage for 50 milliseconds.


The EBCM detects that the relay contacts do not open when the relay is not energized.


A shorted ABS pump motor may damage the contacts within the system relay


Clear Trouble Codes & see if it happens again or replace EBCM & ABS Pump

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