I was reading threw the 2005 dodge diesel owners manual Page 335 and came across this page talking about the OBDII diognostic system. Know in dealing with modifiying cars in the past I know that OBD 2 and beyond has two O2 sensors one to montor exhaust to check A/F ratio and one to read the amount of emissions u are putting out in the atmospher.

Well from what I can gather the 600-610 dont have OBD2 well from the stand point that I dont see any O2 sensor's on the exhaust. Well in the book it talks about how if these systems are not working properly it would throw a Check engine light or throw codes and it would basicly kill gas milage and put the truck in limp mode.

My buddy has a 04.5 and killed the kitty and just has a muffler well after that mod he never threw a code or CEL cause how is the system gona know if it has no sensor after the cat. Well his gas milage has kinda gone in the crapper he has other parts contributing to it lift tires etc

So will u throw a code or CEL if u kill the kitty and is the CPU gona know and fuel the truck differnt and hurt your milage or is the book talking about more extensive problems suck as evaporitive systems or EGR From what I gather the cummins does not have either so wherer is the OBD2 on this truck if the book says it has one etc.

sorry for long post just curios

-Chris

 

No. OBDII for diesel is different than gas until 2007.

 

Ya I figured that but I have no idea as to why the stupid book talks about it. Must be talking about the extra injector that is keeping the CAT lit. So I gathering that killing the kitty will do nothing more that cause more soot and make the truck louder but will not harm any kind of Computer system files that will make the truck fuel or drive differently correct?

-Chris

 

Should have killed the muffer and kept the cat.

 

The computer doesn't know or care about the CAT. I temporarily removed mine to see what would happen and no code was set. It was a little louder, smelled different, and a very very small increase in mileage.

Here's a quote from the web about OBDII:

"On-Board Diagnostic systems are in most cars and light trucks on the road today. During the '70s and early 1980's manufacturers started using electronic means to control engine functions and diagnose engine problems. This was primarily to meet EPA emission standards. Through the years on-board diagnostic systems have become more sophisticated. OBD-II, a new standard introduced in the mid-'90s, provides almost complete engine control and also monitors parts of the chassis, body and accessory devices, as well as the diagnostic control network of the car."

 

i took the muffler and cat off. i made sure there were no sensors on the cat before i got it cut off. i noticed NO CHANGE in fuel mileage