OBD BASIC KNOWLEDGE

Author:huawu

Company:AutoOBDTools

WebSite:http://www.autoobdtools.com

1. What is OBDII(On-Board Diagnostic)?

2. OBD (DLC)Data Link Connector & Protocol List

3. OBD Trouble Codes

4. learning this can saving much money on car repair

1.What is OBDII(On-Board Diagnostic)?

On-Board Diagnostics or OBD was primarily to meet EPA emission standards.b

efore January 1, 1996 called OBD-1.function is simple.

after January 1, 1996.OBD-II, a new standard provides almost complete engine

control and also monitors parts of the chassis, body and accessory devices, as

well as the diagnostic control network of the car.

OBD-II is an expanded set of standards and practices developed by SAE and ad

opted by the EPA and CARB (California Air Resources Board) for implementatio

n by January 1, 1996.

SAE Official website:http://www.sae.org/

EPA Official website:http://www.epa.gov

CARB Official website:http://www.arb.ca.gov/homepage.htm

2.OBD (DLC)Data Link Connector & Protocol List

Data Link Connector The Location Of 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 12 inches from the center of the instr

ument panel (dash),under or around the driver’s side for most vehicles.if you ca

n't find it,you can refer owner manual or search on google

Since 1996, the data link connector (DLC) is a standardized 16 cavity connector sh

own below.Connector design and location is dictated by an industry wide standar

d. Vehicle manufacturers can use the empty DLC cavities for whatever they would

like.however,the DLC of every vehicle is required to provide pins 4 and 5 and 16 as

defined below. When the Controller Area Network (CAN) protocol is fully implemen

ted in the 2008 model year, all vehicles must use pins 6 and 14 as defined below.

Terminal 2 - SAE J1850 10.4k bits per second (BPS) variable pulse width serial data (GM Cl

ass2) or SAE J1850 41.6k bps pulse width modulation serial data high line (Ford).

Terminal 4- Scan tool chassis ground.

Terminal 5 - Common signal ground for serial data lines (Logic Low).

Terminal 6 - ISO 11898/15765/SAE J2284 CAN serial data high line.

Terminal 7 - ISO 9141 K serial data Line or ISO 14230 (Keyword 2000) serial data line (Daim

lerChrysler/Honda/Toyota)

Terminal 10 - SAE J1850 41.6k bps pulse width modulation serial data low line (Ford).

Terminal 14 - ISO 11898/15765/SAE J2284 CAN serial data low line.

Terminal 15 - ISO 9141 L serial data Line or ISO 14230 (Keyword 2000) serial data line (Dai

mlerChrysler/Honda)

Terminal 16 - Scan tool power (Unswitched battery positive voltage)

OBD Protocol List An OBD2 compliant vehicle can use any of the five communication prot

ocols:

1.SAE J1850 PWM

2.SAE J1850 VPW

3.ISO9141-2

4.ISO14230-4 (KWP2000)

5.ISO 15765-4/SAE J2480

Detail:http://blog.autoobdtools.com/car-repair-terms/obd2obd-iiobd-protocol-list/

3.OBD Trouble Codes

Diagnostic trouble codes(dtcs) explain

OBDII Diagnostic Trouble Codes(DTCS) are codes that are stored by the on-board comput

er 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 mi

ght be occurring within a vehicle. OBDII Diagnostic Trouble Codes consist of a five-digit al

phanumeric code.the first character,a letter,identifies which control system sets the code.t

he other four characters,all numbers,provide additional infomation on where the DTC origi

nated and the operating conditions that caused it to set

4.learning this can saving much money on car repair

Why I Say that? When your car run rough, the first thing you do is to take your car to the mecha

nic. Have you noticed what the first thing mechanic do for your car? Yes, conne

cting your car with a scanner. Then you should pay a diagnostic charge. The m

ore times you get your car diagnosed, the more money you should pay. It really

consumes you a lot of money.isn’t it?

What if you have your own scanner? Surely you can save much diagnostic cost.

What’s more benefited, with an auto scan tool, you can find your car problems

at anytime anywhere by yourself. Then you can solve some easy problems with

out the help the mechanics. That’s to say, auto scan tool may enable you to be i

ndependent from those auto repair stores.

Thanks

• Author:huawu

• Company:AutoOBDTools

• WebSite:http://www.autoobdtools.com

• AutoOBDTools Learning Center:http://blog.autoobdtools.com