Today my CEL came on, checked the codes with my OBD-2 reader and it showed P0172 - System too rich (bank 1).
Now.... what exactly does this mean,what could cause this, what is bank 1, and what do I do about it ????

[sm=confused06.gif]....... HELP!!

btw... I have not noticed any changes on how the engine runs. It runs as smooth as it has in the past... !

 

system too rich bank 1.. thats your before cat o2 sensor.. sounds like the cat might be plugged.. pull the o2 sensor.. clean it up good.. try that first.. but to me it sounds like cat is plugged

 

O2 sensor might have gotten lazy. It has to switch between rich and lean very quickly. If it stays rich or lean too long it will throw a code.
How many miles on your engine? Has the O2 ever been changed? If the O2 has over 60k it's a good candidate for replaement. They can loose their sensitivity over time

 

^+1
Check o2 sensor and map sensor. Both can be checked with a scanner.

Rich codes are generated when your long term fuel trims exceed -32% for a period of time.

 

Rabbler, my truck has 104,000 miles on it. I bought it a year ago so I am not sure if the O2 sensor has ever been replaced.

If the sensor is bad shouldn't I have also received a code on it? The only code I got was the P0172

 

I must be blind.. I cannot find any sensors between my exaust manifolds and the CAT !!!

Where is it?? Anyone have pics or can tell me where my before CAT O2 sensors are?