[85silvereldo]

Getting slight miss at idle at times, in car code check says P 0603, can I reprogram it or where can I get done and how much on average to do. thanks

 

[rodnok01]

Re: PO603 code help 99 deville

Don't forget to post code definition(s) and if current or history.

If you've unhooked battery lately you'll have history code about voltage/comms.
If it's history, clear it and see if pops again.

 

[Byrdman]

Re: PO603 code help 99 deville

anytime you post codes, post the definitions, too. Find them here: http://www.cadillacfaq.com/faq/answers/dtccode.html
The codes are a letter, followed by four numbers, followed by Current or History. You can reset codes but that doesn't fix anything, it only turns off the SES light until the fault is detected again. Only "P" codes will trip the SES light.

 

[85silvereldo]

where is the pcm and ground for it for the 99 deville, thanks

 

[rodnok01]

Pcm under the airbox, ground is either on radiator support or below it can't remember exactly.

 

[85silvereldo]

thanks