Brake Pulsation (Two-mode Hybrid)

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2012 GMC Yukon XL, 2012 GMC Yukon, 2012 Chevrolet Tahoe, 2012 Chevrolet Suburban, and 2012 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

Step	Action	Yes	No
DEFINITION: Fluctuation or pulsation is felt through the brake pedal, steering wheel, seat, floor, and/or in the vehicle ONLY when braking. Notchy or uneven brake pedal feel during brake apply. Kickback is felt through the brake pedal during brake apply and release.
1	Were you sent here from the Hydraulic Brake Symptom table?	Go to Step 2	Go to Symptoms - Hydraulic Brakes
2	Inspect the disc brake system for the following conditions: Excessive thickness variation of rotor friction surfaces Excessive assembled lateral runout (LRO) of rotor friction surfaces Hard spots, heat checks, bluing discoloration of rotor friction surfaces; possibly due to brake drag Excessive corrosion of rotor friction surfaces; including red, gray or black oxidation Loose, damaged or missing caliper or lining hardware Bent or damaged caliper or mounting component Excessive LRO of wheel hub/axle flange; due to damage and/or loose or excessively worn bearings Perform the disc brake system diagnostic procedure. Refer to Disc Brake System Diagnosis . Adjust, repair or replace components as necessary. Did you find and correct a condition?	Go to Step 8	Go to Step 3
3	Inspect the brake hydraulic and assist systems for the following conditions: Lack of lubrication, binding, excessively worn and/or damaged brake pedal pushrod, pin and/or pedal pivot bushings. Bent or damaged pedal pushrod, pedal, or pedal bracket. Restricted brake master cylinder reservoir-to-brake pressure modulator valve (BPMV) feed and/or return hoses. Perform the entire brake and hydraulic assist system diagnostic procedure. Refer to Brake Hydraulic and Assist System Diagnosis (Two-mode Hybrid) . Adjust, repair or replace components as necessary. Did you find and correct a condition?	Go to Step 8	Go to Step 4
4	Does the brake pedal feel notchy or uneven during brake apply?	Go to Step 6	Go to Step 5
5	Is kickback felt through the brake pedal during brake apply and release?	Go to Step 7	Go to Symptoms - Hydraulic Brakes
6	Replace the brake master cylinder for sticking or improperly functioning pistons. Refer to Master Cylinder Replacement (JD9) , Master Cylinder Replacement (JH6) , Master Cylinder Replacement (Two-mode Hybrid) . Pressure bleed the hydraulic brake system. Refer to Hydraulic Brake System Bleeding (Pressure) , Hydraulic Brake System Bleeding (Two-mode Hybrid) , Hydraulic Brake System Bleeding (Manual) . Perform the entire Antilock Brake System Automated Bleed . Did you find and correct a condition?	Go to Step 8	Go to Symptoms - Hydraulic Brakes
7	Replace the brake pressure modulator valve (BPMV) for an improperly functioning boost circuit. Refer to Brake Pressure Modulator Valve Replacement . Pressure bleed the hydraulic brake system. Refer to Hydraulic Brake System Bleeding (Pressure) , Hydraulic Brake System Bleeding (Two-mode Hybrid) , Hydraulic Brake System Bleeding (Manual) . Perform the entire Antilock Brake System Automated Bleed . Did you find and correct a condition?	Go to Step 8	Go to Symptoms - Hydraulic Brakes
8	Install or connect components that were removed or disconnected during diagnosis. Road test the vehicle in order to confirm proper operation. Refer to Brake System Vehicle Road Test . Is the condition still present?	Go to Step 2	System OK