Air Antilock Brake System Diagnosis Flashcards
Explain the first step in troubleshooting an antilock brake system.
If at all possible speak directly with the operator in order to get accurate first hand information about the perceived ABS problem. At a minimum, review the customer and service advisors comments on the work order.
Identify the three areas involved in a pre check of the antilock brake system.
a. integrity of connections.
b. physical damage.
c. use of tires of unequal sizes.
What other technical resource do you have if you are unable to determine the cause of an ABS system problem?
Accessing specialized technical support service staff is an option that is available though most ABS manufacturers.
Identify the types of diagnostic equipment that is typically used to access advanced fault codes.
Advanced fault codes are usually accessed by a hand held scan tool that is equipped with a specific ABS diagnostic cartridge. A laptop computer that has appropriate ABS diagnostic software installed can also retrieve advanced fault codes.
Checking the condition of the wiring harness asn associated connections is often done with an ohmmeter. The following should be part of the wiring harness/connection test process.
a. Ensure power to the system is off.
b. Set to ohmmeter for the applicable scale.
c. Use the appropriate ABS service manual to identify the specific test pins/sockets.
d. compare test readings with specific ABS component specifications.
e. All of the above steps are crucial for safe and accurate harness/connection testing.
e. All of the above steps are crucial for safe and accurate harness/connection testing.
Increased wheel bearing wear and consequent increase in play, has no effect on the position of the tone ring in relation to the wheel speed sensor.
True
False
False, end play can move the tone ring away from the sensor.
In order to definitely identify an ECU or ECU/modulator valve as a defective item, advanced ABS diagnostic equipment should be used.
True
False
True
Diagnosing an ABS system problem often starts when the ABS indicator/warning light is activated.
True
False
True
Troubleshooting charts and ABS service manuals are not required as long as you have blink codes.
True
False
False
Identify the three areas involved in a pre-check of the basic service brake system.
a. Brake adjustment
b. Condition of mechanical components.
c. Air system operation
This condition, security and integrity of the electrical cables and connections used on the antilock brake system are areas most likely to cause antilock brake system problems.
True
False
True
Basic ABS diagnostics typically involve the use of:
a. specialized scan tools.
b. a laptop computer that has ABS diagnostic software installed.
c. built-in diagnostic equipment on the truck or trailer.
d. appropriate ABS and/or vehicle service manuals.
e. both c and d.
e. both c and d.
The condition of an ABS indicator/warning light is first checked as part of a daily bulb check processes.
True
False
True
The resistance value of each wheel speed sensor and integral electrical cable can be checked with an ohmmeter. The overall circuit resistance (wheel speed sensor, integral cable and cable to the ECU connector) can also be checked with an ohmmeter.
True
False
True
The modulator valve may be affected by problems within the ABS electrical system as well as problems within the vehicle service brake air system.
True
False
True
