Cab and Hood Flashcards
(112 cards)
When inspecting the key condition, what should you look for?
Inspect the vehicle keys for wear, nicks, bends, or other damage.
When inspecting the ignition switch, what should you ensure
Ensure that the ignition switch is securely mounted and operates smoothly without binding and provides constant port a the accessory, on, and crank positions.
I the truck is equipped with a push-button start switch, how should it operate?
It should operate easily without sticking while properly closing the cranking circuit when depressed.
What is a driver ID code or card used for?
It is used with trucks that have a keyless ignition system
Describe the earlier lamps or indicator lights.
Earlier lamps were small, round lights that were color-coded for their system; yellow for a warning or caution in a non-safety-related system and red for safety-related system warnings.
What systems still use lights?
Major or Safety related systems.
What kind of lights do many non-safety systems use?
Light Emitting Diodes (LED) behind a pictogram of the system it is monitoring.
Why are LED lights such an improvement?
This improvement allows for less electrical current usage in the instrument panel and more reliable operation.
What are the benefits of the self-check feature?
It illuminates all warning lamps when the ignition switched first switched to the on position.
This lets the driver and/or technician know that the lamp and circuit are operational.
What are alarms and buzzers used for in some systems?
For low-pressure (which is mandatory) and for low oil pressure.
The low pressure must sound when the system air pressure drops in below 50 percent of the governor cut-out pressure (approximately 60 psi)
When checking the operation of instruments/gauges and panel lighting, what will a short circuit in the sending unit wire to the gauge do?
It will lower resistance in that circuit, causing the gauge needle to read high.
What will a short circuit to ground in a sending unit wire cause?
It will cause an overload of current to the gauge, which will burn out in a very short time.
Although not considered an official criterion for out-of-service (OOS) status what will a malfunctioning oil pressure gauge cause?
It may be cause for an inspector to deadline a vehicle because a no-oil pressure condition can rapidly destroy and engine.
In performing a proper and thorough check of a vehicle’s instrument panel, as a part of any PMI, what happens when the ignition is first turned on?
Electronic gauges perform a self-test by sweeping the needles.
What does PTO stand for?
Electronic Power Take-Off
How do modern diesel engines mange idle speed and shutdown?
By computer control. This is sometimes a PTO function when the engine speed is set to operate auxiliary equipment.
How can idle speed be raised and lowered?
By the use of a toggle switch provided on the dash.
How does a programmed engine shutdown occur?
After the desired time interval, when the desired time has elapsed, without input from the throttle pedal of the clutch pedal, the engine will shut down automatically.
What would you use to change the programmed time?
An electronic service tool. (EST)
How does the automatic stop/start features work?
Most engine management Systems have stop/restart features that expand the normal idle shutdown feature to further reduce idle time.
They will automatically stop and restart when require to hold engine temperature about a programmed specific value, maintain the battery charge level, and to keep the cab/sleeper at a temperature level programmed into customer parameters.
What are other benefits of having automatic stop/start features?.
Other benefits claims are reduced emissions, noise, and engine life.
What conditions must be in order for the stop/restart feature to be enabled?
- One OEM system requires that the ignition switch be on, the engine idling with the idle shutdown timer enabled, the hood closed, the transmission in neutral or park, the parking brake set, and the master cruise switch in the on position.
What happens when the system determines to start the engine?
Based on sensor inputs, the active lights illuminates and an alarm in the engine compartment sounds, and the engine cranks.
If the engine fails to start, will a second attempt occur?
Yes, a second attempt will occur in 45 seconds.