xv System Operation . . . . . . . . . . . . . . . . . . . . . . 365 Hydraulic Control during ABS Braking. . . . . . . . . .365 Hydraulic Control during TCS-Assisted Acceleration . . . . . . . . . . . .366 Manufacturers of Anti-Lock Brake, Traction Control, and Electronic Stability Control Systems . . . . . . . . . . . . . . . 368 Common ABS, TCS, and ESC Systems . . . . . . . . . .368 Chapter 22: Anti-Lock Brake, Traction Control, and Electronic Stability Control System Service. . . . . . . . . . . . . . . . . . . . 371 Working on ABS/TCS/ESC Systems. . . . . . . . . . 372 ABS/TCS/ESC System Maintenance. . . . . . . . . . . . .372 Performing Brake Service on ABS/TCS/ESC-Equipped Vehicles . . . . . . . . .372 Preparing to Diagnose ABS, TCS, and ESC Problems . . . . . . . . . . . . . . . . . . . . 374 Performing a Road Test . . . . . . . . . . . . . . . . . . . . . . .374 Using Service Information. . . . . . . . . . . . . . . . . . . . .376 Visual Inspection. . . . . . . . . . . . . . . . . . . . . . . 376 Mismatched Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . .376 Brake Fluid Level and Base Brake Hydraulic Problems. . . . . . . . . . . . . . . . . . . . . . . . .376 Power Brake Booster. . . . . . . . . . . . . . . . . . . . . . . . . .376 Worn or Misadjusted Friction Members . . . . . . . . .376 Vehicle Charging System Problems . . . . . . . . . . . . .376 Wiring Problems and EMI/RFI Interference. . . . . .377 ABS, TCS, and ESC System Diagnosis . . . . . . . . 377 Trouble Code Retrieval. . . . . . . . . . . . . . . . . . . . . . . .377 Using Scan Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . .378 Checking for Vehicle Electrical Problems . . . . . . . .379 Checking Wheel Speed Sensors . . . . . . . . . . . . . . . .381 Checking and Adjusting the Brake Light and Pedal-Travel Switches . . . . . . . . . . . . . . . . . . .383 Checking Steering Angle Sensors . . . . . . . . . . . . . . .383 Checking G-Force Sensors. . . . . . . . . . . . . . . . . . . . .383 Checking Yaw Sensors . . . . . . . . . . . . . . . . . . . . . . . .384 Checking Control Module and Related Circuits. . .384 Checking Integral Hydraulic Actuators . . . . . . . . . .384 Traction Control System Diagnosis . . . . . . . . . . . . .386 Replacing ABS, TCS, and ESC System Parts. . . . 388 Replacing Speed Sensors . . . . . . . . . . . . . . . . . . . . . .388 Replacing G-Force and Yaw Sensors. . . . . . . . . . . . .389 Replacing Pedal Travel Switch and Brake Light Switch. . . . . . . . . . . . . . . . . . . . . .390 Replacing the Control Module . . . . . . . . . . . . . . . . .390 Servicing Hydraulic Actuator Assemblies . . . . . 390 Hydraulic System Service. . . . . . . . . . . . . . . . . . . . . .390 Bleeding the System . . . . . . . . . . . . . . . . . . . . 393 Bleeding Using a Scan Tool . . . . . . . . . . . . . . . . . . . .394 Flushing the System . . . . . . . . . . . . . . . . . . . . . . . . . .394 Follow-Up after ABS/TCS/ESC Repairs. . . . . . . . . .395 Chapter 23: Troubleshooting Brake Systems. . . . . . . 397 Filling out Work Orders . . . . . . . . . . . . . . . . . . 398 Obtaining Vehicle Identifi cation Numbers. . . . . 398 Strategy-Based Diagnostics . . . . . . . . . . . . . . . 398 The Seven-Step Troubleshooting Procedure . . . 401 Step 1—Verify the Complaint . . . . . . . . . . . . . 401 Talking to the Driver. . . . . . . . . . . . . . . . . . . . . . . . . .401 Step 2—Check for Obvious Problems . . . . . . . 403 Performing Visual Inspections . . . . . . . . . . . . . . . . .404 Step 3—Determine Which Component or System Is the Most Probable Cause . . . . . 404 Diagnosing Intermittent Problems. . . . . . . . . . . . . .404 Step 4—Perform Pinpoint Tests . . . . . . . . . . . . 405 Step 5—Isolate and Recheck the Causes of the Problem . . . . . . . . . . . . . . . . . 406 Always Perform Additional Tests . . . . . . . . . . . . . . .406 Deciding on Needed Work. . . . . . . . . . . . . . . . . . . . .407 Contacting the Owner about Needed Work . . . . . .407 Step 6—Correct the Defect(s) . . . . . . . . . . . . . 408 Step 7—Recheck System Operation . . . . . . . . 408 Follow-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408 Additional Diagnostic Tips . . . . . . . . . . . . . . . . . . . .408 Documentation of Repairs. . . . . . . . . . . . . . . . . . . . .409 Remaining Calm . . . . . . . . . . . . . . . . . . . . . . . . . . . . .409 Noise, Vibration, and Harshness. . . . . . . . . . . . 410 Principles of Vibration . . . . . . . . . . . . . . . . . . . . . . . .410 Creating and Transmitting Noise . . . . . . . . . . . . . . .411 Sources of Harshness . . . . . . . . . . . . . . . . . . . . . . . . .411 Eliminating Noise, Vibration, and Harshness. . . . .411