Vehicle Communication Systems Exam V2 2026/2027 | ASE/SAE-Aligned Automotive Electronics | Verified Questions & Answers | 100% Correct

Vehicle Communication Systems Exam V2 2026/2027 | ASE/SAE-Aligned Automotive Electronics | Verified Questions & Answers | 100% Correct If an oxygen sensor indicates an AFR(rich AFR) which could cause the condition? High Fuel System Pressure Which OBDII codes signify an Idle Control Circuit P0505 While manually performing an OBDII drive cycle test, which system will be tested during 2 1/2 mins if idling after start? Canister Purge, O2 system and Cat Converter will be tested later because it require heat to properly read the system. OBD II equipped vehicle has MIL but will not communicate with the scan tool. What would cause the issue? Non-compliant CAN scan tool Which publication contains procedures for retrieving diagnostic trouble trees? Service Manual Which on board controllers should be checked for information on the power window? BCM On boad diagnostic system publishes U0029, Vehicle communication Bus a Performance, which tool should you use to test networking wiring? High Speed Lab Scope In order to replace a splayed pin on a PCM harness, which of the following should be used? Terminal Tool OBD II protocol ensures that an MIL will illuminate when tailpipe emission exceed Federal Test procedures by what %? 50% higher or 1 1/2 times the limit In order to properly start a drive cycle test to verify a system fix, what should the ECT be less than? 50C or 122F If the active suspension were to incur a fault, what would be the generated code start with an OBD II C for Chassis V8, OBD compliant hesitate a few mins after a hot soak restart condition and then runs fine, which sensor is more likely to cause this condition? Oxygen sensor Most common cause of Hard to Start when engine is at operating condition. Advance ignition timing Oxygen sensor reading of 450mV is an average value on an engine at normal operating temp and at closed loop. what will happen when a vacuum leak occurs? Voltage reading will go down, vacuum leak will cause more Oxygen in the exhaust and lean condition Which of the following input sensors should produce nearly the same reading on a vehicle at the moment of start up after being shut down for 12 hours? ECT and IAT how many OBD II pin connector has ? 16 Minimum number of freeze frames captured by an OBD II after it has set? 1 Which vehicle system do all OBD II type A and B diagnostic trouble codes relate to? Emission control. There are 2 categories of DTC in OBD II, Type A and B both relate to Emission. Type A is most severe, but Type B has pending codes and erase code if necessary. Which pin in a standard 16 pin is reserved for chassis ground? Pin 4 is chasis ground, Pin 5 is signal ground. Pin 2 is Communication BUS + and Pin 10 is Communication BUS - How is a warm up cycle defined for purposes of OBD II code log clearance? Event which the ECT exceeed 70*C and deactivate only after PCM detects 3 warm up cycles whic DTC not detected. If you unplug the coolant temperature sensor terminal from the coolant sensor on a warm engine, what will happen? DTC will indicate open and the result would be at minimum or low. Low voltage output from the O2 sensor located upstream from the cat converter would indicate what condition? Low voltage output would indicate lean condition. a cracked exhaust manifold is more likely the caused as it pulled the air from cracked manifold. Low O2 voltage=more O2 is being used up=lean High O2 voltage+less O2 is being used =rich Which of the following running condition would likely require a richer stoichiometric air fuel mixture. Idling. leaner mixture is required for normal cruising and light load. Richer mixture is required for idling and heavy load and hard acceleration. Ping noted on 89 octane fuel when accelerated, what is the remedy for the condition? Change to higher octane fuel. What happen when vaccum hose on the fuel regulator on port injected fuel injection system is removed. It will increase, when the system vaccum drop as if the throttle is fully opened. and increase the rail pressure Noid light illuminates but appears dim, what condition it indicates? High resistance in the fuel injector wiring or connector Fuel pump produce a whining noise, what to do first before replaceing the pump? Replace the fuel filter You have tested the set of injectors with over 200K on odometer, you've found 3 to be defective, what is your next move? Recommend replacing all 6 injectors be installed Vaccum hose is removed from fuel regulator and drip of fuel were seen, what is the cause? Leaking fuel regulator diaphragm. When scoping a pulse width actuated injector, where should be the inductive kick (spike) occurs on the graphic? At the end of the pulse width profile. You are scoping one of a set of injectors in a port injected fuel system and observe the inductive kick displayed in the graphic is gradually reduce in length as the engine warms to operating temperature, what is the likely cause? injector pulse width is shortened as the engine reaches operating temperature. If the oxidizing stage of cat converter on a gasoline engine is fuctioning properly, which of the following should be true regarding exhaust gas temperatures once the engine is at operating temperature? Converter out should be 15% warmer than converter in temperature. What type of ignition system eliminates spark plug wires? Coil on plug Which of the following whould be true of the shield used on an optical ignition sensor? It must be light proof. When troubleshooting a distributionless ignition system you identify a defective high tension wire. Which of the following should be replaced along with the wire? Coil. A defective high tension wire almost always destroy the coil that fires it. The high voltage that produce by the coil deprive of its intended ground path arc with in the coil. creating a short circuit to the primary windings known as carbon track. When platinum spark plugs are to be reused. Which of the following is correct procedures. Coat thread lightly with anti seized and donot attempt to recap. When scoping a good pair of plugs on a waste spark ignition system. what should distinguish the power spark from the waste spark on the osciliscope pattern. Firing line is higher on the power spark. When you disconnect a high tension wire on a running engine while troubleshooting an ignition problem. what must you do? Ground the high tension wire Which of the following categories of devices is used to signal input data to an ECM during engine operation? sensors What type of device is used as a coolant temperature sensor on a typical truck engine management system? NTC thermistor What is the usual V-Ref value in truck engine management systems? 5 V-DC What type of output does an induction pulse generator used to read shaft or rotor speed produce? AC Which of the following fits the description of multiplexing? multiple vehicle computers networked by a data bus The non-volatile, read/write/erase memory component in a truck ECM is known as: EEPROM What type of mass airflow (MAF) sensor measures pressure differential at two points either side of a venturi? critical flow venturi What is a stepper motor used for? precision positioning of a shaft When processing the signal from an inductive pulse generator used to measure shaft rotational speed, which of the following is used to process the signal to an rpm value? frequency Technician A says that some types of NOx sensor use a galvanic operating principle. Technician B says that galvanic type NOx sensors must be powered up using V-Ref. Who is correct? A only Technician A says that a WIF sensor uses a couple of probes that measure dielectric properties of water versus fuel. Technician B says that dielectric properties refers to electrical resistivity. Who is correct? both A & B Which of the following is commonly used to convert the results of ECM processing into action? actuators When two truck electronic systems are required to exchange information and their operating protocols do not match, what is required to make communication possible? interface or gateway module Which of the following memory categories is designed to be the most permanent? ROM To which of the following memory categories would the master program for engine management be written in a typical truck engine ECM? ROM To which of the following memory categories would customer data programming be written from an electronic service tool? EEPROM Which of the following components conditions V-Ref? ECM A thermistor is responsible for signaling data concerning: temperature Which of the following components uses a voltage divider principle and can be used to signal accelerator pedal travel? potentiometer In a full authority diesel engine management system, EUI switching is performed by: injector drivers The Media Oriented System Transport (MOST) cooperation data bus system uses fiber optics to transmit data. T or F True Wireless networks require the use of one wire to transmit information. T or F False The Controller Area Network (CAN) system can support baud rates up to 5 Mb/s. T or F True The ISO-K bus protocol allows for bidirectional communication on a single wire. T or F True Technician A says J1850 protocol is the class B standard for OBD II. Technician B says the J1850 standard allows for four different versions based on baud rate. Who is correct? A Bluetooth technology allows several modules from different manufacturers to be connected using a standard high definition transmission. T or F False Multiplexing (MUX) networks allow several devices to share signals on a common conductor. T or F True Each computer is connected to the data bus is called a mole. T or F False Multiplexing (MUX) wiring systems use bus data links that connect modules together. T or F True Controller Area Network (CAN) bus diagnostics is being discussed. Technician A says a scan tool is used to access the central gateway module for the bus network. Technician B says if the scan tool can communicate with the central gateway module, then the CAN C circuit is at fault. Who is correct? A The local interconnect network (LIN) bus is a UART singe master, multiple slave, low speed network. T or F True The Controller Area Network (CAN) was developed to supplement the local interconnect network (LIN) bus system. T or F False Technician A says the LIN bus is a UART single master, multislave, low-speed network. Technician B says the local interconnect network (LIN) was developed to take the place of the CAN bus system. Who is correct? A Controller Area Network CAN B bus diagnostics is being discussed. Technician A says some modules do not set specific codes that isolate the type of fault. Technician B says if the fault code indicates both CAN B+ and CAN B- circuits are low or high, a total bus failure has occurred. Who is correct? Both Technician A says ISO 9141-2 is not a network protocol since it can be used only for diagnostic purposes. Technician B says ISO 9141-2 is a Class B system that has a baud rate of 10.4Kb/s. Who is correct? Both Technician A says modules on the Media Oriented System Transport (MOST) data bus use an LED, photodiode, and a MOST transceiver to communicate with light signal. Technician B says the Media Oriented System Transport (MOST) system uses fiber optics to transmit data at an extremely fast rate. Who is correct? Both Controller Area Network (CAN) bus diagnostics is being discussed. Technician A says the first step is to verify the customers complaint. Technician B says you must determine which bus network is at fault. Who is correct? Both Technician A says wireless networks can connect modules together to transmit information with the use of electromagnetic field. Technician B says Bluetooth technology allows several modules from different manufacturers to be connected using a standardized radio transmission. Who is correct? B Technician A says the circuitry of the CAN bus usually consists of a pair of twisted wires. Technician B says for digital data to transfer the CAN bus voltage is simultaneously pulled high on one circuit and pulled low on the other. Who is correct? Both All of the following are facts about Controller Area Network (CAN) bus diagnostics, Except: -A normal voltmeter reading on the CAN B (+) circuit with the ignition in the RUN position is between 280 and 920 mv. -A normal voltmeter reading on the CAN B (+) circuit with the ignition in the OFF position and the bus asleep is zero volts. -A normal voltmeter reading on the CAN B (-) circuit with the ignition in the RUN position is between 4.08 and 4.72 v. -A normal voltmeter reading on the CAN B (-) circuit with the ignition in the OFF position and the bus asleep is zero volts -A normal voltmeter reading on the CAN B (-) circuit with the ignition in the OFF position and the bus asleep is zero volts