On Board Diagnostic Quiz

Technician A says that both OBD I and OBD II systems will pinpoint a sensor that is operating poorly or incorrectly. Technician B says that OBD I will only indicate that a circuit is no longer operating properly. Who is correct?

• Technician A only

• Technician B only

• Both Technician A and B

• Neither Technician A nor B

The malfunction indicator light in an OBD II system is flashing. Technician A says that this simply indicates a soft failure. Technician B says this means the problem could be damaging the catalytic converter. Who is right?

• Technician A only

• Technician B only

• Both Technician A and B

• Neither Technician A nor B

Technician A says an automotive computer can scan its input and output circuits to detect incorrect voltage problems. Technician B says an automotive computer can scan its input and output circuits to detect an incorrect resistance problem. Who is right?

• Technician A only

• Technician B only

• Both Technician A and B

• Neither Technician A nor B

Unplugging the computer harness connector with the engine running could cause a computer-damaging ______________________________.

• noise.

• voltage spike.

• corrosion.

• no start.

An OBD II system will identify problems with all the components listed except ____.

• battery temperature sensor

• ignition coil

• oxygen sensor

• starter solenoid

Trouble codes set by an OBD I system can be read manually by each of the following methods except ____.

• counting flashes of the check engine light

• counting deflections of the needle on an analog voltmeter

• counting beeps of the vehicle’s horn

• reading a digital display in a climate control panel

The data link connector for an OBD II system most often will be located ____.

• behind the front bumper

• under the dash or center console, near the driver’s seat

• behind the dash on the passenger’s side of the vehicle

• on the firewall, inside the engine compartment

The number 1 appearing as the first digit in an OBD II trouble code indicates that the trouble code is ____.

• manufacturer-designated

• standard (SAE)

• system-specific

• not erasable

A trouble code indicates that there is no activity in an oxygen sensor circuit. Technician A says to test the sensor and its circuit. Technician B says to replace the sensor. Who is right?

• Technician A only

• Technician B only

• Both Technician A and B

• Neither Technician A nor B

A wiggle test is being performed on an automotive computer system. Technician A performs this test with the engine off and the ignition key off. Technician B performs this test with the engine off and the ignition key on. Who is right?

• Technician A only

• Technician B only

• Both Technician A and B

• Neither Technician A nor B