Reading codes

[Emerald94]

Quick question.
I'm going to check my codes this weekend but was wondering if I should do it while the engine is warm or cold (or does it matter?)?

 

[LI_SHO]

Ideally you want the car at operating temperature for all tests...so you dont get false ECT and ACT codes.
Consult the "codes" section of www.midwestsho.com, they have a very thorough write up =)

 

[Emerald94]

Thanks for the reply Dan. thumbs_u
As a matter of fact, I did go to the MidWest SHO website and printed the write up but didn't see anything about operating temperatures.

 

[projectSHO89]

You can run the KOEO codes without warming the engine up.

To run the KEOER tests, one of the first directions is to run the engine to operating temp, then run at 1500-2000 RPM for two minutes to heat the O2 sensors properly.

ACT sensor testing is independent of engine temperature. These sensors are sensitive to ambient temperatures and any ACT code which is extracted while the ambient temp is below 50F is to be ignored.

Steve