190204a Flashcards
True or false. Vehicle speed sensor’s and engine RPM sensors provide a variable frequency signal to the CM. The signals can be used to operate a speedometer or Tachometer
True
Pressure sensors are typically wired to the ECM using how many wires in the circuit
Pressure sensors are typically wired to the ECM with a three wire circuit
True or false. When a coolant level sensor probe is installed in the radiator, the coolant forms a path for current to flow between the two terminals of the probe.
True. liquid completes the circuit
A typical throttle position sensor uses a potentiometer to provide the ECM with the variable DC voltage signal that varies between what volts
0.5 V DC at idle and 4.5 V DC at full throttle
What are three forms of diagnostic information generated by the ECM
Fault codes, flash codes and diagnostic trouble codes
True or false. SAE has developed a generic fault code system. This system enables you to retrieve similar information regardless of the fault code systems used by different engine manufacturers
True
True or false. fault codes can only be generated to indicate engine protection problems
False. Fault codes can be generated to indicate engine protection problems and electronic system problems
True or false. Warning lights are output devices and are part of the engine protection system
True. Warning lights are located on the dash panel to alert the operator when I monitored system has developed a problem
Using a laptop how would you would adjust low idle speed up.
Reprogram the idle speed setting within a fixed set of parameters.
True or false. electronic control systems typically have programmable parameters that can be changed to tailor system operation and meet customer requirements
True.
A TPS ( throttle position sensor) is
** on test**
A potentiometer device the provides ECM with electrical signal proportional to the amount of pedal depresstion
What are three purposes of engine warning lights
Alert the operator of a problem affecting engine performance, indicate engine danger or damage if left unchecked, used to retrieve diagnostic trouble codes
What are two diagnostic instruments that can be attached to the DDL connector
Hand held Scan tool or computer with the appropriate adapters
And electrical open in a temperature sensor circuit would produce a trouble code indicating that the sensor circuit voltage is what?
Higher than the normal range of sensor values
What information would the ECM provide for a fault if an electrical SHORT developed in a temperature sensor circuit.
The ECM would create an active code indicating the sensor circuit voltage is “LOW”
Typically can customer adjustable parameters exceed set values that are established by the engine manufacture.
Not a chance. Customers can only adjust within those parameters
What equipment would you need to interface with the ECM
And adapter cable, a communication adapter and the appropriate software loaded on the PC
A temperature sensor is also called a
Thermistor
a thermister has _____ resistance when cold, and has ________ resistance when hot
High
Low
A pressure sensor is a
3 terminal device
1 wire connected to 5volt DC
2 wire connected to sensor return or ground
3 wire signal wire to ECM
A speed sensor or reluctance type is
Commonly use to provide the ECM with info on RPM ( tachometers) or vehicle speed( speedometers)
Generally speaking what manuals in electronic format would you get as part of the engine manufacturers diagnostic software package
Service and troubleshooting manual
What are some factors that determine the frequency from the vehicle speed sensor VSS
Rear axle ratio, tire revolutions per mile based on tire size, number of teeth on the transmission output shaft pulse wheel and top gear ratio of the transmission
Cruise control speed settings are based on the frequency of what signal device
Vehicle speed sensor. VSS
Before working on electronic equipment what are two possible ways you can discharge static electricity
Touch a ground surface or attach a grounding strap to the vehicle frame and yourself while working
What three options can typically be selected to determine the level of engine protection
Warning, de-rate, shut down
Fuild level sensor does what
Detect the operating levels of coolant or oil.
Cruise control speed settings are based on the frequency of the signal from what kind of sensor?
(VSS) Vehicle speed sensor
What are the benefits of an electronic fuel control system?
- improved throttle response
- improved cold starting and warm up characteristics
- less mechanical linkages and components
- engine warning and shut down systems can be integrated
What does a basic electronic control system consist of?
- input devices
- ECM
- output devices
Senses, switches, and data links are all examples of?
Input devices (provide signals to ECM)
True or False? Engine RPM, vehicle speed, and oil pressure are all monitored by actuators?
False. Actuators are output devices
An Electronic Control Module contains which of the following? A) Central processing unit (CPU) B) input sensors C) actuators D) All of the above
A. The others interact with the ECM
True or False?
RAM memory is referred to as a type of read/write memory
Thus is true donkey
And it’s volatile. Loss of power can wipe it out.
Technicians can access ECM operation by connecting a scan tool or PC to the… ?
Data Link Connector
True or False? EPROM Memory can be reprogramed while the EPROM memory chip is still installed in the ECM.
False.
EEPROM can be reprogrammed while in the ECM
True or false? The Electronic control system can perform functions previously handled through mechanical and hydraulic governors.
True
Multiplexing (networking) is used to connect computer controlled systems. What else do they allow for?
- Simplified engine diagnostics
- Less complex than older systems
- Information can be shared between computer modules
What is the definition of Baud rate?
The speed of communication between the modules
Define protocol relating to electronic control systems
Protocol refers to the common language used between the modules.
What’s an actuator
An output device that receives signals from the ECM
True or false
Digital signal is either on or off between two fixed voltages
True
Usually between 0 to 5 volts with ECM circuits
What’s a parameter
Programmable feature, value or instruction that affects operation characteristics of an engine
What are sensors
Sensors and input devices that monitor pressure, temperature, fluid levels and mechanical movements
What are the components of a basic electronic control system
Input sensors
ECM
Output devices
Three basic functions of the warning system?
1-to warn the operator of an engine or system malfunction
2-to de-rate or shut down the engine when damaging conditions exist
3-to generate fault codes to assist system diagnosis
Three levels of engine protection I can be programmed into the ECM?
1-warning only
2-warning and de-rate
3-warning, de-rate, and shut down
The ECM compares sensor information with stored parameters to determine?
The ECM compare sensor information with stored parameters to determine when An electronic system or engine problem exists
The two basic types of diagnostic code systems used are?
Engine manufacturer fault codes
Society of automotive engineers (SAE) fault codes
Engine manufacturer codes can be separated into 2 sections
Engine protection codes
System fault detection codes
Engine protection codes deal with faults that will cause engine damage or failure such as
Low oil pressure high oil temperature high coolant temperature Low oil level low coolant level High inlet air temperature
Why was the SAE fault code system developed?
The S a E fault code system was developed to standardize the fault code numbering system throughout the industry. the benefit of the system is that basic diagnostics can be performed using a standard set of codes regardless of engine manufacturer.
What is FMI?
Failure mode identifier - this identifies The type of failure occurring such as voltage low, voltage high, or data out of range. FMI failures are identified by a 2 digit numeral ranging from approximately 00 to 14
What is SID?
System identification - This identifies the operating system affected such as engine position sensor throttle position sensor coolant temperature sensor SID failure types are identified by three digit numeral from approximately 000 to 300
What is PID?
Parameter identification - this identifies a specific parameter affected such as engine oil pressure coolant temperature and turbo boost PID failure types are identified by a three digit numeral from approximately 000 to 300
The ECM generates diagnostic trouble codes based on what two sources of information?
Information from the sensor circuit
Set values programmed into the ECM’s memory
When is an engine protection fault code generated?
An engine protection fault code is generated when ever the sensor signal value is out of range during specific engine conditions
