How to retrieve OBDII error codes

[offroadaz]

Turn the ignition key until the digital odometer displays, repeat three times in succession and then back to "On" (On/Off, On/Off, On/Off, On). At the fourth "On" the odometer will be replaced with codes. If no codes are present then "Done" will appear.

[Spshlj]

How accurate is this? When all that stuff was going on with my Jeep I did that a couple times and it never displayed a code, only done.

[offroadaz]

if your check engine light is on then this will pull down the same codes as the OBDII scanner

[Spshlj]

What does it actually check? My oil pressure gauge is all messed up and it is not reading a code. My engine light is not on just my check gauge light.

[offroadaz]

as far as I know it will only pull down codes from your check engine light

[sweathog]

for quick reference:

97 and up codes (displayed in the odometer):
http://www.stu-offroad.com/engine/scancodes.htm

92-96 (flash counts from the Check Engine Light):
http://www.jeep-xj.info/HowtoECUcodes.htm
http://www.jedi.com/obiwan/jeep/dtc.html

[jeepmare]

Correct it will only pull "check engine light" codes.