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Ask Chad Farhat Your Own Question
Chad Farhat
Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems
Category: Chevy
Satisfied Customers: 1535
Experience:  Owner at Carolina Auto Service & Sales , 20 years Experience in Foreign & Domestic vehicles A6 - Electrical / Electronic systems A7 Heating / Air Conditioning systems
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Code co265 &service brake booster, I check the fuses don't

Customer Question

code co265 &service brake booster
JA: Have you checked all the fuses? Do you have a wiring diagram?
Customer: I check the fuses don't have diagram
JA: What is the model/year of your Chevy?
Customer: 2004 silverado
JA: Are you fixing your Silverado yourself? What have you tried so far?
Customer: cleaned ground wires under drivers door
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 2 months ago.
Category: Chevy
Expert:  Chad Farhat replied 2 months ago.

Hi, I'm Chad. Welcome to JustAnswer. I'm reviewing your question and I will be posting your reply ASAP.

Expert:  Chad Farhat replied 2 months ago.

Have went down the steps in the diagram i sent you

and was the EBCM replaced already ?

what is the mileage on it ?

is there any other codes than the C0265

Please let me know

Thank You

Chad Farhat

ASE Certified Technician

DTC C0265 or C0266

Circuit Description The ABS relay supplies battery voltage to 6 valve solenoids. The electronic brake control module (EBCM) microprocessor applies the grounds needed to activate each solenoid. The low side of each solenoid coil has a feedback circuit to the EBCM microprocessor. When a solenoid is commanded OFF, the feedback voltage is high. When a solenoid is commanded ON, the feedback voltage is low. Conditions for Running the DTC ^ The ignition is ON. ^ The vehicle speed is greater than 6 km/h (4 mph). Conditions for Setting the DTC ^ The EBCM detects an internal malfunction ^ Low system voltage ^ Open ground at the EBCM Action Taken When the DTC Sets C0265 If equipped, the following actions occur: ^ The EBCM disables the DRP/ABS. ^ The ABS indicator turns ON. ^ The brake warning indicator turns ON. C0266 If equipped, the following actions occur: ^ The EBCM disables the ABS. ^ The ABS indicator turns ON. Conditions for Clearing the DTC The conditions for setting the DTC are no longer present and you use the scan tool Clear DTCs function. Diagnostic Aids Important: Whenever the EBCM is replaced for DTC C0265 or C0266, the ABS pump motor and motor circuitry must be tested for the proper resistance. Refer to steps 7 and 8 in the diagnostic table below for testing procedures and resistance values. Check ground G110 for an open or a high resistance. Check the EBCM power supply for an intermittent open. C0265 Thoroughly inspect connections and circuitry that may cause an intermittent malfunction. C0266 Replace the EBCM if DTC C0266 continues to set intermittently. Test Description The numbers below refer to the step numbers on the diagnostic table. 4. This step tests if the battery positive voltage circuit can supply adequate power to the system relay. 7. A shorted ABS pump motor or shorted motor circuitry may damage the contacts within the system relay. Follow this step to prevent damage to a replacement EBCM.