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
