The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

**hatzie** · 04-28-2020, 09:02 AM

I'm a big fan of troubleshooting.
The code scanners are sometimes useful but they fall on their face when you need sensor data to troubleshoot a problem.

My first step is to take the exact OBD code(s) and google "GM Pxxxx code set criteria". This will tell you what the PCM uses as criteria to set the code(s) in question. Once you know that you have a place to begin looking for the problem.
If you post the codes here it'll help narrow things down. There are an awful lot of codes for MAP, O2, EGR etc so a vague knowledge of the general area the codes were pointing doesn't really help us help you.

This is where a more comprehensive bi-directional diag tool helps a lot.

Can you get a look at live (engine running) fuel trims, MAP, MAF, EGR state, O2 sensor, and other sensors with your existing tool?

04-28-2020, 09:02 AM	#16
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,912	Re: Low power on 2001 6.0 I'm a big fan of troubleshooting. The code scanners are sometimes useful but they fall on their face when you need sensor data to troubleshoot a problem. My first step is to take the exact OBD code(s) and google "GM Pxxxx code set criteria". This will tell you what the PCM uses as criteria to set the code(s) in question. Once you know that you have a place to begin looking for the problem. If you post the codes here it'll help narrow things down. There are an awful lot of codes for MAP, O2, EGR etc so a vague knowledge of the general area the codes were pointing doesn't really help us help you. This is where a more comprehensive bi-directional diag tool helps a lot. Can you get a look at live (engine running) fuel trims, MAP, MAF, EGR state, O2 sensor, and other sensors with your existing tool? __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful. Last edited by hatzie; 04-28-2020 at 09:07 AM.