CEI CEI Vehicle Inspection & OBD Systems 1 — Questions and Answers
Question 1: What does OBD-II stand for in the context of vehicle emission inspections?
- On-Board Diagnostics, second generation (Correct answer)
- Output-Based Detection, version 2
- Onsite Breakdown Detection, second edition
- Optional Board Data, second generation
Correct answer: On-Board Diagnostics, second generation
OBD-II stands for On-Board Diagnostics, second generation, a standardized system required on all US vehicles since 1996 to monitor emission-related components.
Question 2: Which OBD-II readiness monitor must be in a 'complete' or 'ready' state for a vehicle to pass an emission inspection?
- All required monitors must show complete or ready (Correct answer)
- Only the catalyst monitor needs to be ready
- Only the oxygen sensor monitor needs to be ready
- At least one monitor must show complete
Correct answer: All required monitors must show complete or ready
For a vehicle to pass an OBD-II emission test, all required readiness monitors must be set to complete or ready, indicating the self-tests have run and passed.
Question 3: What is the maximum number of OBD-II readiness monitors that can be 'not ready' on a 1996–2000 MY vehicle without causing an automatic OBD test failure in most US states?
- 2 monitors not ready (Correct answer)
- 1 monitor not ready
- 3 monitors not ready
- 0 monitors not ready
Correct answer: 2 monitors not ready
For model year 1996–2000 vehicles, most state I/M programs allow up to 2 readiness monitors to be incomplete before the vehicle automatically fails the OBD portion of the test.
Question 4: A Malfunction Indicator Lamp (MIL) illuminated solid during an OBD-II inspection indicates what?
- A stored Diagnostic Trouble Code related to an emission system fault (Correct answer)
- The vehicle's battery is low
- The vehicle passed the emission test
- A temporary sensor glitch with no fault code stored
Correct answer: A stored Diagnostic Trouble Code related to an emission system fault
A solid MIL (Check Engine Light) indicates one or more Diagnostic Trouble Codes (DTCs) are stored, signaling a detected emission-related fault.
Question 5: Which connector port is used to access OBD-II data during a vehicle emission inspection?
- DLC (Data Link Connector), a 16-pin J1962 port (Correct answer)
- OBD port, a 9-pin RS-232 connector
- ELD port, a 6-pin diagnostic connector
- CAN bus port, a 4-pin OBDII adapter
Correct answer: DLC (Data Link Connector), a 16-pin J1962 port
The Data Link Connector (DLC), standardized as a 16-pin J1962 connector, is the interface used to plug in scan tools and access OBD-II data.
Question 6: What does a 'P0420' diagnostic trouble code indicate on an OBD-II equipped vehicle?
- Catalyst system efficiency below threshold (Bank 1) (Correct answer)
- Oxygen sensor circuit malfunction (Bank 1, Sensor 1)
- Evaporative emission control system leak detected
- Mass air flow sensor circuit range/performance problem
Correct answer: Catalyst system efficiency below threshold (Bank 1)
P0420 is a generic OBD-II code indicating the catalytic converter efficiency on Bank 1 has dropped below the minimum threshold required by the ECU.
CEI CEI Vehicle Inspection & OBD Systems 1
What does OBD-II stand for in the context of vehicle emission inspections?