obd 2 codes explained (read your own codes)

[chad8]

OBD-II Diagnostic Trouble Code Database

Enter OBD-II Diagnostic Trouble Code:


A DTC is made up of 5 digits. The figure below demonstrates the composition of a OBD-II Diagnostic Trouble Code.
OBD-II Diagnostic Trouble Codes
OBD-II Diagnostic Trouble Codes Explained

OBD-II codes consist of a number of parts. Below 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 = Power train
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 equipped 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.

 

[Lead Shoes]

P0440 is my new headache :0

changed the gas cap, lights still on, now i guess i gotta take it in

 

[Steve S]

Originally Posted By: Brenden
P0440 is my new headache :0

changed the gas cap, lights still on, now i guess i gotta take it in

Did you clear or have the code cleared?

 

[Lead Shoes]

yeah i undid the battery for like 15sec's, but haven't had the code cleared with a reader.

 

[Eddie]

You need to clear a gas cap code with a reader OR it will take 10+ warm ups to turn off the light. battery cable removal will not clear codes I'm told.

 

[GMBoy]

Originally Posted By: Eddie
You need to clear a gas cap code with a reader OR it will take 10+ warm ups to turn off the light. battery cable removal will not clear codes I'm told.



That is true, you need to clear OBD2 codes with a scanner. The old battery cable disconnect won't do it and actually causes more harm than good since you now have to reset all your presets and the car has to relearn all it's parameters.

NO true DIY'er should be without a good scan tool.

 

[yeti]

eddie -- it likely depends on the vehicle.what i've used -- remove battery cable, and hold ignition in the start position for about a minute. it does work. you'll likely hear about different methods.

 

[ls1mike]

Lots of cars are different. On the LS1 F-body you can pull the PCM ign and PCM bat fuses in that order wait a bit, put them back in and you are good to go.

 

[aussiek2000]

Originally Posted By: Brenden
P0440 is my new headache :0

changed the gas cap, lights still on, now i guess i gotta take it in

what car? i'll look it up for you.

 

[chad8]

you need a obd 2 code reader to reset this cars code. Free at autozone. you can buy one at harbor freight for $39.

Possible Solutions


1. Remove and reinstall the gas cap, clear the code, and drive for a day and see if the codes come back.
2. Inspect the EVAP system for cuts/holes in tubes/hoses
3. Inspect for damaged or disconnected hoses around the Evap purge solenoid
4. Check and/or replace the sensor
5. Check and/or replace the purge valve
6. Have a professional use a smoke machine to detect leaks
7. gas filler tube is rusted
8. gasket at filler tube to tank has failed
9 charcoal canister has been comprised from overfilling gas tank or just wore out. replace.

Just Reset the light when it comes on. This is the famous Al Gore light. Makes no difference in performance of vehicle.It was a bad idea from the beginning. A system designed to capture gasoline vapors destined to fail.

 

[brianl703]

Originally Posted By: GMBoy
The old battery cable disconnect won't do it


Actually, it will on some cars. It does on both my '06 Saab 93 and my '97 Ford Crown Vic. On both of those cars, disconnecting the battery cable clears any stored codes and sets all the readyness monitors to "not ready". (Really on the Crown Vic I just pulled the 3-amp PCM keep-alive fuse, but disconnecting the battery would have the same effect).

 

[Jimmy9190]

Thanks for the code info. I had P0441 come up last week. I fixed a split hose at the evap test port and thought that was it, but the CEL came back on yesterday, same P0441 code. I couldn't find any cracked hoses so I tried the next most logical and cheapest repair and bought a new gas cap last night.

On my truck I can cycle my ignition key on and off 3 times and the emissions trouble codes display in the odometer. I can also disconnect my negative battery terminal and hold the key in start for 30 seconds to clear codes, but on this problem AAP cleared the code both times for free.