I'm not sure which section to post this question, but here goes. I've noticed that the diagnostic trouble codes in this forum usually start with the letter P (or C) and are followed with four numeric digits. I don't own a scanner/analyser, although the prices have come down so far it may be a good investment, so I can't really relate to those threads. Instead I have always just jumped pins a and b together on the output diagnostic terminals and turned on the ignition and then watched the "service engine light" flash to get the code. I guess I'm just old school, my truck is a '91, a second vehicle. I now have code 45, "rich exaust indication", according to the manual. What should I do? Upgrade?, I guess, right? These are the codes you see on scanners, the P or C with four digits?

 

What are you going to upgrade? I would think "rich exhaust" could mean incomplete combustion in one or more cylinders, failing PCV valve, failing EGR valve....or other things that the guys who are way smarter than me can help you with.

 

OBD1 codes are only two digits and can be "read" with the paper clip trick.

OBD2 codes require a scan tool to be able to read them and there are MANY more codes available. The sticky at the top of the DTC section gives the breakdown for OBD2 trouble codes --> ODBII - Trouble Codes

 

I checked some of those things you mentioned but need to get a vaccuum pump to test the EGR valve, emission diagnostics are allways tough for me. I guess my question is this; should I invest in a scanner tool or is my truck too old to show any type 2 codes that the tool is able to scan for? In other words, can I retreive any additional codes with a scanner that my truck will not show with the flashing method?

 

Since you have a 91 (from what I remember - Would help if you would put that information in your signature), a scanner will not really help you much other than keeping you from having to watch the CEL.