OBD II

When does the DTC auto clear?

If no additional detected faults after 40 consecutive warm-up cycles

What does PCV stand for?

Positive Crankcase Ventilation

What happens to the Readiness Status when you use the DTC erase function on the scan tool?

Readiness Status for monitors stays the same

When the MIL is on, a technician should do these 2 things...

Retrieve the DTC & follow the manufacturer's recommended procedure to diagnose

Multiplexed systems

Several components displays and controllers are connected in a single network

Which monitor can cause the MIL to flash?

The Misfire Monitor

What happens when a cylinder fires?

The crankshaft picks up speed

What happens when a cylinder misfires?

The crankshaft slows down

DTC P0302

generic DTC

3 Kind of DTCs

generic, common, vehicle manufacturer's specific DTCs & data displays

Which monitors may not run when the O2 sensor stops?

1) CAT 2) EVAP 3) EGR

What are 3 ways the MIL turns off?

1) Codes cleared with scan tool 2) Vehicle drive on 3 consecutive trips with warm-up cycle w/o detecting fault 3) Power to PCM disconnected

Name 3 Non-continuous monitors

1) EGR monitor 2) Catalyst monitor 3) Oxygen sensor monitor

Which 3 sensors can affect the Misfire Monitor operation?

1) Fuel level sensor 2) Crankshaft sensor 3) MAP sensor

Name 3 Continuous monitors

1) Fuel system monitor 2) Comprehensive component monitor 3) Misfire monitor

What 3 things could cause there to be no change in the short-term fuel trim when the PCM commands the EGR to open?

1) The vacuum line to the EGR is disconnected 2) The EGR valve is stuck shut 3) The EGR passages are clogged with carbon

Warm-up cycles

1) erase DTCs and freeze frame data 2) Counted by the PCM when the engine is started, the coolant temperature reaches 160 degrees F, and there is an increase in coolant temperature of at least 40 degrees F

Hexadecimal

1) the format for some global (generic) OBD II data 2) Always preceded by a dollar sign ($) 3) Are base 16 4) Can be converted to base 10

OBDII has been on all US passenger vehicles since this year

1996

Drive Cycle

A driving procedure that enables all monitors to run

OBD II

A monitoring system used to detect an increase in vehicle emissions above 1.5 times the emission levels established during the FTP; monitors all emission-related components

Trip

A set of driving conditions that provide enabling criteria for a monitor or monitors to run successfully

Comprehensive component monitor

Checks computer-controlled devices for 1) Functionality 2) Opens 3) Rationality

What does CCM stand for?

Comprehensive Component Monitor (OBD II)

What are the Rich-Lean Threshold and Lean-Rich Threshold constants used to measure in scan tool Mode $05?

Cross counts

DTC P0442

DTC that could indicate that the gas cap is loose or defective

Freeze frame

Element of the OBD II diagnostic management system which stores engine data during a DTC set

What does EVAP stand for?

Evaporative Emission Control System

What does EGR stand for?

Exhaust Gas Recirculation.

OBD I was capable of detecting exhaust emission control system failures. True or False?

False

What does MIL stand for?

Malfunction Indicator Lamp

What does MAP stand for?

Manifold Absolute Pressure sensor

What does MAF stand for?

Mass Air Flow sensor

Which OBDII monitor has no OBDI test procedure equivalent?

Misfire monitor

What does OBD stand for?

On-board diagnostics

When is a "pending code" set? (also known as pending or maturing fault)

The first fault of a two-trip fault

What does it mean when the MIL is on?

There is a DTC stored in memory / emission-related DTC matures

What's least likely to cause the MIL to not illuminate?

There is an open in the circuit between the ground side of the MIL and the PCM (NOT - the bulb is burned out, the fuse supplying power to the MIL is open, or there is a short to ground between the ground side of the MIL and the PCM)

Type of DTC for ignition misfire/fuel mixture problem

Type A

When is a freeze frame generated on an OBD II vehicle?

When a Type A or Type B DTC is set

When can a smog test be performed?

When all OBD II monitors have "enable" criteria achieved