SCT OBD Systems & Diagnostics 2

Question 1

What DTC prefix indicates a generic (SAE-standardized) emissions-related powertrain fault in the OBD II system?

Accepted Answer

P0 (Generic Powertrain)

Answer

B0 (Body)

Answer

C0 (Chassis)

Answer

U0 (Network Communication)

Question 2

What does a 'pending' DTC in an OBD II system indicate?

Accepted Answer

A fault detected once but not yet confirmed through a second drive cycle

Answer

A fault that has been confirmed and stored as a permanent code

Answer

A code that only exists when the MIL is continuously illuminated

Answer

A historical code stored from a previous model year inspection

Question 3

What engine parameter does OBD II standard PID $05 (Mode 01, PID 05) report?

Accepted Answer

Engine coolant temperature

Answer

Engine RPM

Answer

Vehicle speed

Answer

Throttle position percentage

Question 4

How many consecutive confirmed detections (drive cycles) does an OBD II system typically require before setting a confirmed DTC and illuminating the MIL?

Accepted Answer

Two consecutive drive cycles

Answer

One drive cycle

Answer

Five drive cycles

Answer

Ten drive cycles

Question 5

What does the OBD II oxygen sensor monitor evaluate during its self-test?

Accepted Answer

The response time and output voltage range of upstream and downstream O2 sensors

Answer

The physical insulation condition of the oxygen sensor wiring harness

Answer

Whether the oxygen sensors are the correct OEM part number for the vehicle

Answer

The oxygen content of ambient air entering the engine air filter

Question 6

Which OBD II communication protocol became mandatory for all light-duty vehicles sold in the United States starting with model year 2008?

Accepted Answer

ISO 15765-4 (CAN)

Answer

ISO 9141-2

Answer

SAE J1850 VPW

Answer

SAE J1850 PWM

Question 7

What action must a smog technician take when a vehicle arrives for inspection with a flashing (blinking) MIL?

Accepted Answer

Immediately fail the vehicle, as a flashing MIL indicates active catalyst-damaging misfires

Answer

Proceed with the test but note the flashing light in the inspection report

Answer

Reset the MIL with a scan tool and retest to see if it illuminates again

Answer

Only fail the vehicle if P0300-range misfire codes are also stored