3. The red brake warning lamp is dimly lit on a rear-wheel-drive pickup with RWAL. Which is the most likely cause?
A. Hydraulic system failure
B. Computer malfunction
C. Antilock braking system fault
C
4. Technician A says that cell phone or CB antenna interference can disrupt the antilock braking system (ABS) control unit. Technician B says that many system problems can be located with a thorough visual inspection. Who is correct?
A. Technician A
B. Both Technicians A and B
C. Technician B
D. Neither Technician A nor B
https://biology-forums.com/index.php?topic=399827.06. Tires slip about _______ percent during ABS braking.
A. 10
B. 5
C. 20
D. 30
Tires slip about 20% during an ABS stop.
7. Technician A says that the traction control system shouldn't be diagnosed in the same way as the electronic stability control (ESC) system. Technician B says that using a spare tire on the drive wheel can set off the traction control and/or ESC amber warning light. Who is correct?
A. Technician B
B. Both Technicians A and B
C. Neither Technician A nor B
D. Technician A
I think tech A is wrong.
Traction control (TC) can be
separate or used as part of the electronic stability control (ESC) system.
Traction control allows an ABS system to control wheel spin during acceleration. When tires lose traction during acceleration, it is called positive slip.
I think tech B is right, using a spare could throw off the traction control.
9. Why would putting a larger tire on a vehicle interfere with the ABS operation?
A. The tire size doesn't affect ABS operation.
B. The wheel speed sensor on that wheel will give a slower speed reading than it should.
C. The wheel speed sensor on that wheel will give a faster speed reading than it should.
D. It will increase the air gap in the wheel speed sensor.
I'm thinking B
11. An ABS amber warning light that comes on as soon as the vehicle starts indicates a
A. failed modulator solenoid.
B. blown ABS pump fuse.
C. bad wheel speed sensor.
D. low brake-fluid level.
C
A fault in a wheel speed sensor (WSS) is a common ABS problem. A quick and easy test that works on most Bosch ABS systems (and perhaps others) involves the following steps:
STEP 1 Hoist the vehicle safely.
STEP 2 Turn the ignition on (engine off).
STEP 3 Spin a tire by hand as fast as possible.
STEP 4 The ABS amber warning light should come on, indicating that a speed was detected but not by all the wheel speed sensors.
STEP 5 Turn the ignition off to reset the ABS warning light.
STEP 6 Repeat the test on each of the remaining wheels.
12. An ABS systems that use a conventional master cylinder and vacuum booster for power assist, what type of accumulator is used as a temporary storage reservoir for brake fluid?
A. Solenoid
B. Nitrogen-charged chamber
C. Spring-loaded diaphragm
D. This type of system doesn't use an accumulator.
I think the answer is C, or perhaps I misread the textbook... [See the attachment below]
13. Two technicians are discussing installation of a new wheel speed sensor. Technician A says that the protective plastic on the tip of the unit should be left in place during installation. Technician B says that in some units, this plastic will be impossible to remove once installed and so it should be removed first. Which technician is correct?
A. Technician B only
B. Technician A only
C. Both Technician A and Technician B
D. Neither Technician A nor Technician B
I think Tech A is right because it may act as a spacer.
Most sensors adjust by first loosening a set screw, then inserting a nonmagnetic brass or plastic feeler gauge between the tip of the sensor and a high point on the tone ring.
15. For an antilock brake system (ABS) to function properly, the driver must _______ while steering the vehicle.
A. pump the brakes
B. apply the brakes very lightly
C. release the brakes
D. keep the brakes applied
From experience, with ABS, all you have to do is "brake and steer".
So, D?
16. The _______ is common to vehicles equipped with an antilock braking system (ABS).
A. hydraulic control unit
B. pedal travel sensor
C. combination valve
D. pressure-relief valve
A
17. Technician A says that a flashing electronic stability control (ESC) system light indicates when the ESC system is operating to help restore vehicle stability. Technician B says that vehicles using traction control systems can reduce engine torque in slippery driving conditions. Who is correct?
A. Both Technicians A and B
B. Neither Technician A nor B
C. Technician B
D. Technician A
Tech B is right. Now, tech A.
When the lamp is on or flashing, it indicates that a low traction condition has been determined and the traction control system is working to restore traction. A flashing traction dash light does not indicate a fault.
I'd say both are correct.
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