Exam 107: Abs Diagnosis and Service

Most wheel speed sensors should measure how much resistance?

Technician A says no wheel speed sensors are adjustable. Technician B says improper tire size can cause ABS system faults. Which technician is correct?

Technician A says interference from cell phone or CB antennae may the disrupt the ABS control unit. Technician B says many system problems can be located with a thorough visual inspection. Which technician is correct?

When observing WSS output with an oscilloscope, most sensors should produce ________.

Two technicians are discussing magnetic-type wheel speed sensors. Technician A says that wheel speed sensors are magnetic. Technician B says that the toothed sensor ring is magnetic. Which technician is correct?

A good wheel speed sensor should produce at least ________ with the wheel turning.

A quick diagnostic test of wheel speed sensors (WSS) on some Bosch ABS systems is to hoist the vehicle and spin each tire individually. If the WSS is working properly ________.

Technician A says that the ABS electrohydraulic unit can be bled using bleeder screws and the manual method. Technician B says that a scan tool is often required to bleed the ABS electrohydraulic unit. Which technician is correct?

A wheel speed sensor is producing lower than expected voltage as the wheel rotates. Which of these is NOT a possible cause?

Technician A says that a breakout box is often required to diagnose an antilock braking system. Technician B says that a breakout box requires to use of a digital multimeter. Which technician is correct?

What reference voltage (supply voltage) is used with digital wheel speed sensors?

1996 and newer vehicles need to use a scan tool to retrieve ABS diagnostic trouble codes.

Technician A says that a noise or vibration may be sensed by the driver when the ABS performs a self test. Technician B says that the ABS fuse may have to be removed to erase some ABS diagnostic codes if a scan tool is not used. Which technician is correct?

Technician A says that the test drive is an important diagnostic step to verify customer ABS concerns. Technician B says that if the red brake warning light is on, the conventional brake system should be repaired first, before driving. Which technician is correct?

The red brake warning lamp is on and the amber ABS lamp is off. Technician A says that a fault is possible in the base brake system. Technician B says that the red brake warning lamp can be turned on by a low brake fluid level in the master cylinder. Which technician is correct?

How are the antilock system valves activated on a Kelsey-Hayes 4WAL system?

Technician A says that, with some antilock braking systems, the diagnostic trouble code may be lost if the ignition is turned off before retrieving the code. Technician B says that some antilock braking systems require that a terminal be grounded to cause the amber ABS warning lamp to flash diagnostic trouble codes. Which technician is correct?

Technician A says that a scan tool may be required to retrieve data and diagnostic trouble codes from some antilock braking systems. Technician B says that a jumper wire can be used to retrieve diagnostic codes on some antilock braking systems. Which technician is correct?

The red brake warning lamp is dimly lit on a RWD pickup with RWAL. Which is the most likely cause?

The ABS computer uses what signal characteristic from a wheel speed sensor?