Mechanic tells me that my 7.3 is getting p0603 code. He is saying that its a sensor that needs to be replaced but I'm having a hard time finding anything about this code and how to correct it. I have seen that it may have to do with a battery/alternator problem and a bunch of other things. I hadn't serp belt snap and that obviously caused the alternator not to spin and I got the batt light to come on. Don't know if that could have caused this code. I am not getting any lights on my dash (engine etc) and my gauges work fine. Any help would be greatly appreciated.

My second issue is that I am being told that the cylinder test shows a malfunction in number 8. Which i am to believe is caused by a bad injector. I trust the knowledge of you guys on this forum and would like your opinion on this diagnosis as well.

I was also told that my high volume oil pump is bad and can't recall what led them to believe that but I am fairly certain it was one of the 2 problems listed above. Thank you in advance..

 

P0603 could be any of the following:
- Loose or poor battery terminal connection
- Low battery charge or recently disconnected
- ECM power supply circuit is open or shorted
- ECM Programing
- Faulty ECM

In my case, it is caused by the programmer that I have installed. If I uninstall the programmer, the code goes away. It has never turned the CEL on.