Editing On board diagnostics (section)

==OBD-II codes==
OBD-II codes consist of a number of parts. Here is a sample OBD2 code:

P0171

Here is a breakdown of what each digit of the code means:

'''First Character - System'''
The first character identifies identifies the system related to the trouble code.

P = Powertrain 

B = Body 

C = Chassis 

U = Undefined 

'''Second Digit - Code Type'''
The second digit identifies whether the code is a generic code (same on all OBD-II equpped vehicles), or a manufacturer specific code.

0 = Generic (this is the digit zero -- not the letter "O") 

1 = Enhanced (manufacturer specific) 

'''Third Digit - Sub-System'''
The third digit denotes the type of sub-system that pertains to the code

1 = Emission Management (Fuel or Air)
 
2 = Injector Circuit (Fuel or Air) 

3 = Ignition or Misfire 

4 = Emission Control 

5 = Vehicle Speed & Idle Control 

6 = Computer & Output Circuit 

7 = Transmission 

8 = Transmission 

9 = SAE Reserved 

0 = SAE Reserved 

'''Fourth and Fifth Digits'''
These digits, along with the others, are variable, and relate to a particular problem. For example,a P0171 code means P0171 - System Too Lean (Bank 1).

===See Also===

http://forums.seloc.org/viewthread.php?tid=112517
https://wiki.seloc.org/a/Lotus_20/20_diagnostic_Software