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2. SaFETy
WaRNING! To prevent personal injury or damage to vehicles and/or the scan tool, read this instruction manual first and observe the
‰
following safety precautions.
Always perform automotive testing in a safe environment.
9
Wear safety eye protection.
9
Keep clothing, hair, hands, tools, test equipment, etc. away from all moving or hot engine parts.
9
operate the vehicle in a well ventilated work area. exhaust gases are poisonous.
9
Put blocks in front of the drive wheels and never leave the vehicle unattended while running tests.
9
use extreme caution when working around the ignition coil, distributor cap, ignition wires and spark plugs. these components
9
create hazardous voltages when the engine is running.
Put the transmission in PArK (for automatic transmission) or neutrAL (for manual transmission) and make sure the parking brake
9
is engaged.
Keep a fire extinguisher suitable for petrol/chemical/electrical fires nearby.
9
DO NOT connect or disconnect any test equipment while the ignition is on or the engine is running.
8
Keep the scan tool dry, clean, free from oil/water or grease. use a mild detergent on a clean cloth to clean the outside of the
9
scan tool, when necessary.
3. GENERaL INFORMaTION
3.1.
On-Board Diagnostics EOBD
the eoBd system is designed to monitor emission control systems and key engine components by performing either continuous or
periodic tests of specific components and vehicle conditions. When a problem is detected, the EOBD system turns on a warning lamp
on the vehicle instrument panel to alert the driver typically by the phrase of "check engine". the system will also store important
information about the detected malfunction so that a technician can accurately find and fix the problem.
3.2.
Diagnostic Trouble Codes
diagnostic trouble codes are codes that are stored by the on-board computer diagnostic system in response to a problem
found in the vehicle. these codes identify a particular problem area and are intended to provide you with a guide as to where a
fault might be occurring within a vehicle. eoBd Diagnostic Trouble Codes consist of a five-digit alphanumeric code. The first character,
a letter, identifies which control system sets the code. The other four characters, all numbers, provide additional information on where
the dtc originated and the operating conditions that caused it to set. Here below is an example to illustrate the structure of digits:
dtc example
P 0 2 0 2
Systems
B=Body
c=chassis
P=Powertrain
u=network
code type
Generic (SAE):Manufacturer Specific:
P0, P2, P34-P39
P1, P30-p33
B0, B3
B1, B2
c0, c3
c1, c2
u0, u3.
u1, u2
3.3.
Location of the Data Link Connector (DLC)
the dLc (data Link connector or diagnostic Link connector) is the standardized 16-cavity connector where diagnostic scan tools
interface with the vehicle's on-board computer. the dLc is usually located 30cm from the center of the instrument panel (dash),
under or around the driver's side for most vehicles. If data Link connector is not located under dashboard, a label should be there
telling the location. for some Asian and european vehicles, the dLc is located behind the ashtray and the ashtray must be removed to
access the connector. If the dLc cannot be found, refer to the vehicle's service manual for the location.
3.4.
EOBD Readiness Monitors
An important part of a vehicle's EOBD system is the Readiness Monitors, which are indicators used to find out if all of the emissions
components have been evaluated by the EOBD system. They are running periodic tests on specific systems and components to
ensure that they are performing within allowable limits.
not all monitors are supported by all vehicles and the exact number of monitors in any vehicle depends on the motor vehicle
manufacturer's emissions control strategy.
continuous monitors - Some of the vehicle components or systems are continuously tested by the vehicle's eoBd system, while
others are tested only under specific vehicle operating conditions. The continuously monitored components listed below are always
ready:
1. Misfire
2. fuel System
3. comprehensive components (ccm)
once the vehicle is running, the eoBd system is continuously checking the above components, monitoring key engine sensors,
watching for engine misfire and monitoring fuel demands.
non-continuous monitors - unlike the continuous monitors, many emissions and engine system components require the vehicle to
© Jack Sealey Limited
Identifying specific
malfunctioning
section of the
systems
Sub-systems
1= fuel and Air metering
2= fuel and Air metering
3= Ignition System or engine
Misfire
4= Auxiliary emission controls
5= Vehicle Speed control and
Idle controls
6= computer output circuits
7= transmission controls
8= transmission controls
Original Language Version
Page 2
VS8812 | Issue 1 27/02/17
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