Glossary

< A mathematical symbol meaning "less than". Usually in the context of "the reading at pin #1 should be < 5 volts.

> The symbol for "more then".

≤ Equal to or less than, no higher than. "The voltage at pin #2 should be ≤10 volts".

≥ Equal to or greater than, no less than.

~ Approximately, close to. "Engine coolant temperature sensor voltage at 68 °F should be ~2.4 volts".

ACRONYM
A word formed from the first letters of the words of a compound term. For example: ISAT (Intelligent Saab Tester).

AIR
An abbreviation for Secondary Air Injection. An emissions system which pumps fresh air into the exhaust stream to reduce HO and CO emissions.

CARB
The acronym for California Air Resources Board. The legislative body which originated the OBD I and OBD II regulations.

CKP
Crankshaft Position (sensor).

CO
Carbon monoxide. An exhaust by-product of incomplete combustion.

CP
Cannister Purge (valve). The solenoid valve controlling venting of the

EVAP
cannister into the intake manifold.

DIAGNOSTIC
Any of a number of on-board tests run by the vehicle's powertrain management systems which check for malfunctions in the vehicle's emission system.

DLC
An acronym for Data Link Connector. This is the standardized 16 pin connector located under the driver-side instrument panel which will be common to all 0BD II vehicles.

DRIVING CYCLE
An important 0BD II term used to define a series of events which, when completed, can trigger an action such as turning on or off the MIL. A Driving Cycle occurs when the engine has been started.

DTC
Diagnostic Trouble Code. Also frequently known as a fault code or just, code.

ECT
Engine Coolant Temperature (sensor).

ECM
Engine Control Module

ENABLE CRITERIA
Operating conditions such as coolant temperature, road speed, etc. which must be met before a diagnostic procedure will run.

EPA
Environmental Protection Agency. The federal department responsible for regulating all forms of environmental pollution.

EVAP
An abbreviation for the Evaporative control system. Normally used as the first word in a J1930 term such as "EVAP Emission Canister".

EVAP CANISTER CLOSE VALVE
An ECM controlled solenoid valve which regulates the flow of purge air from the atmosphere into the evaporative emission canister.

FREEZE FRAME
Operating conditions which are stored in the memory of a controller at the instant which a fault is recorded.

FTP
The acronym for Federal Test Procedure, the automotive emissions tests used by the EPA to measure the emissions output of all cars and light- duty trucks sold in the United States.

FUEL TANK PRESSURE SENSOR
A pressure sensor mounted on the tiller neck of some 900 models. This sensor is part of the hardware needed to monitor EVAP system integrity.

FUEL TRIM
The short and long-term fuel trim diagnostic procedure used by the engine management system to monitor rich or lean conditions in the engine's air/fuel mixture.

HC
An abbreviation for Hydrocarbon. A major component of automotive exhaust. HC is normally associated with raw or unburned fuel, either from a misfire, excessively rich mixture or evaporative loss/leakage.

HO2S
Heated Oxygen Sensor.

IAC
Idle Air Control. Usually seen as a preface for "IAC valve".

IAT
Intake Air Temperature (sensor).

I/M 240
A federally mandated, state administered automobile inspection and maintenance program to improve air quality in designated parts of the country.

ISO
International Standards Organization. In some ways the international equivalent of our SAE.

ISO 9141
The ISO specification data communication network protocol used by Saab and other European vehicles for scan tool communications.

MAF
Mass Airflow. The MAF sensor (previous Saab term was Air Mass Meter) is used by MOTRONIC systems provide the information needed to calculate load.

MAP
Manifold Absolute Pressure. The MAP sensor on the TRIONIC engine management system is one of the primary inputs used to calculate load.

MIL
Malfunction Indicator Lamp, previously often referred to as the "check engine" light.

MISFIRE
When, for whatever reason, combustion does not take place in a cylinder.

NOX
Oxides of Nitrogen. Any of several possible nitrous oxide compounds emitted by automotive exhaust.

OBD I
On-Board Diagnostics Generation One. The on-board automotive diagnostic system required by the California Air Resources Boa?d since 1988.

OBD II
On-Board Diagnostics Generation Two. An expanded on-board system required on all light duty vehicles sold in the United States beginning in 1996.

SAE
Society of Automotive Engineers.

SAE J1850
The SAE document which defines OBD II data stream requirements. This is the scan tool communications protocol used by domestic manufacturers.

SAE J1930
The SAE document which standardizes all powertrain and emissions component names and acronyms used by all manufacturers.

SAE J1962
The SAE document which provides the specifications for the size, shape and pin configuration of OBD II diagnostic tool cable connectors.

SAE J2008
The SAE document which establishes guidelines for making OBD II diagnostic information available to anyone who wants it.

SAE J2012
The SAE document which defines the new 5 digit OBD II diagnostic trouble code format.

TP
Throttle Position Sensor

VVA
Vehicle Vertical Acceleration (sensor). A device used on 4 cylinder MOTRONIC systems to disable the misfire detection diagnostic when driving on rough roads.

WARM-UP CYCLE
An OBD II method for determining when a vehicle has been started from a "cold" condition and run long enough to reach "normal" operating temperature.

This has happened when:
1. Coolant temperature has increased by at least 40°F
AND
2. The final temperature has reached at least 160°F