310T Electrical and Electronic Systems 3

Question 1

A truck's ABS warning lamp stays on after the vehicle exceeds 6 mph. What is the MOST likely cause?

Accepted Answer

Faulty wheel speed sensor or damaged tone ring

Answer

Low brake fluid level

Answer

Worn brake pads

Answer

Incorrect tire pressure

Question 2

When testing a truck's charging system, the technician measures 13.2 V at the battery with the engine running at 2,000 RPM and all accessories on. What does this indicate?

Accepted Answer

Undercharging — alternator output is insufficient

Answer

Normal charging output

Answer

Overcharging — voltage regulator is faulty

Answer

Battery is fully charged and alternator is resting

Question 3

A technician finds excessive resistance in a truck's starting circuit. Which tool is BEST suited to locate the high-resistance connection?

Accepted Answer

Voltmeter performing a voltage-drop test

Answer

Ohmmeter across the open circuit

Answer

Ammeter in series with the battery

Answer

Test light across the starter solenoid

Question 4

On a multiplex (J1939 CAN bus) system, a technician notices multiple modules going offline intermittently. The MOST likely cause is:

Accepted Answer

An open or shorted CAN bus terminating resistor

Answer

Low system voltage

Answer

Faulty ignition switch

Answer

Corroded battery ground strap

Question 5

A coach's air conditioning compressor clutch engages but immediately disengages. Which electrical component should the technician check FIRST?

Accepted Answer

High-pressure and low-pressure refrigerant switches

Answer

Blower motor relay

Answer

Thermostat sensor

Answer

Condenser fan motor

Question 6

What is the purpose of the data link connector (DLC) on a heavy-duty truck?

Accepted Answer

To provide a standardized interface for diagnostic scan tools

Answer

To connect the trailer ABS module

Answer

To supply battery voltage to electronic control modules

Answer

To ground the chassis to the engine block

Question 7

A truck's fuel gauge reads full immediately after filling, then quickly drops to empty. The MOST likely fault is:

Accepted Answer

Shorted fuel level sending unit circuit to ground

Answer

Faulty instrument cluster

Answer

Open circuit between the sending unit and gauge

Answer

Sending unit float is stuck at the top of its travel