On-board diagnostics 2 or OBD2

On-board diagnostics 2 or OBD2

    In my previous post i have explained what is ODB? OBD is nothing but it helps the owner and technician to find out the what is problem in vehicle.OBD2 is the advance version of OBD1, OBD-II is the protocol used by all cars built after 1996

   In OBD2 lot of improvement is done compared to OBD1 ,improvement is like standardization,signaling,diagnostics protocols ect. 
 
OBD 2 connector are standardized:
 In OBD 1 Each manufacturer used their own diagnostic link connector (DLC), DLC location, DTC definitions, and procedure to read the DTCs from the vehicle. DTCs from OBD-I cars are often read through the blinking patterns of the 'Check Engine Light' (CEL) or 'Service Engine Soon' (SES) light. By connecting certain pins of the diagnostic connector, the 'Check Engine' light will blink out a two-digit number that corresponds to a specific error condition.

OBD1

but OBD2 connector is stanardized all the manufacturer using the same connector .We an use any ODB2 scaning tool to scan the CAR.

OBD2

OBD 2 Signal standardization: 

SAE J1850

ISO 14230 KWP2000

ISO 14230 KWP2000

ISO 15765 CAN

ISO 15765 CAN

  

Standardization on OBD2 protocol: 

1. UDS unified diagnostic service(CAN-BUS) 

   • ISO 15765-4 CAN (11 bit ID,500 Kbaud)
   • ISO 15765-4 CAN (29 bit ID,500 Kbaud)
   • ISO 15765-4 CAN (11 bit ID,250 Kbaud)
   • ISO 15765-4 CAN (29 bit ID,250 Kbaud) 
   
   
   
   

  2. ISO14230-4 (KWP2000) 

  3. ISO9141-2 

  4.SAE J1850 VPW 

 5.SAE J1850 PWM