Step | Action | Yes | No | ||||||
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DEFINITION: This diagnostic table is designed to diagnose ONLY the components of the brake ASSIST system in order to determine if the brake ASSIST system is operating properly. You will be directed by the appropriate Symptom table to go to other brake system diagnostic tables as appropriate. | |||||||||
1 | Were you sent here from a Brake Symptom table? | Go to Step 2 | |||||||
2 | Is the symptom related to brake system noise? | Go to Step 4 | Go to Step 3 | ||||||
3 | Is the symptom related to the brake system self-applying when the steering wheel is being turned? | Go to Step 11 | Go to Step 9 | ||||||
4 | Check the hydraulic assist system operation for the presence of abnormal noise. Refer to Hydraulic Brake Assist System Noise Inspection . Did the system operate normally from a noise standpoint? | Go to Step 20 | Go to Step 5 | ||||||
5 |
Did you find and correct a condition? | Go to Step 20 | Go to Step 6 | ||||||
6 |
Was the abnormal noise heard ONLY during brake apply? | Go to Step 13 | Go to Step 7 | ||||||
7 | Perform the Power Steering System Test procedure to determine if there are any restrictions in the system. Refer to Power Steering System Test . Did you find and correct a condition? | Go to Step 20 | Go to Step 8 | ||||||
8 | During the noise inspection, did the hydraulic brake booster produce abnormal noises? | Go to Step 13 | Go to Step 20 | ||||||
9 | Inspect for proper brake pedal travel. Refer to Brake Pedal Travel Measurement and Inspection . Is the brake pedal travel distance within the acceptable limits? | Go to Step 11 | Go to Step 10 | ||||||
10 |
Did you find and replace any worn, missing, misaligned, bent or damaged brake pedal system components? | Go to Step 11 | Inspect for internal and external fluid leaks and air in the hydraulic brake system | ||||||
11 |
Did you complete the inspections and any necessary adjustments or replacements? | Go to Step 12 | -- | ||||||
12 | Inspect the hydraulic brake booster for fluid leaks. Refer to Hydraulic Brake Booster Leak Inspection . | Go to Step 13 | -- | ||||||
13 | Perform the hydraulic booster functional test:
Important: The brake pedal should fall slightly, then hold. Did the brake pedal fall slightly after the engine was started, then hold? | Go to Step 16 | Go to Step 14 | ||||||
14 | Perform the Power Steering System Test procedure to determine if there are any restrictions in the system. Refer to Power Steering System Test . Did you find and correct a condition? | Go to Step 15 | Go to Step 19 | ||||||
15 | Perform the hydraulic booster functional test:
Important: The brake pedal should fall slightly, then hold. Did the brake pedal fall slightly after the engine was started, then hold? | Go to Step 16 | Go to Step 19 | ||||||
16 | Perform the short-term or accumulator reserve leak-down test:
Turn the steering wheel to full-lock position for 2 seconds ONLY and return to rest. Important:
Were both pedal applies power assisted? | Go to Step 17 | Go to Step 18 | ||||||
17 | Perform the long-term reserve leak-down test:
Turn the steering wheel to full-lock position for 2 seconds ONLY and return to rest. Important:
Were both pedal applies power assisted? | Go to Step 20 | Go to Step 19 | ||||||
18 | Replace the hydraulic brake booster accumulator assembly, if applicable. Did you complete the replacement? | Go to Step 20 | -- | ||||||
19 | Replace the hydraulic brake booster assembly. Refer to Power Brake Booster Replacement . Did you complete the replacement? | Go to Step 20 | -- | ||||||
20 | Install or connect any components that were removed or disconnected during diagnosis. Did you complete the operation? | Brake Assist System OK Return to Symptom Table | -- |