P0172 GMC Fuel Trim System Rich Bank 1

Possible causes
– Faulty front heated oxygen sensor
– Ignition misfiring
– Faulty fuel injectors
– Exhaust gas leaks
– Incorrect fuel pressure
– Faulty Mass Air Flow (MAF) sensor
Tech description
There is a factory service bulletin for the following GMC models:

2000-2008 GMC Sonoma
2000-2008 GMC Sierra
2000-2008 GMC Yukon
2000-2008 GMC Yukon XL
2001-2008 GMC Denali
2001-2008 GMC Denali XL
2001-2008 GMC Savana
2002-2008 GMC Envoy
2002-2008 GMC Safari
2002-2008 GMC Jimmy
2000-2008 GMC Factory Service Bulletin OBDII Code P0172

When is the obd code mean?
– Fuel injection system does not operate properly.
– The amount of mixture ratio compensation is too large. (The mixture ratio is too rich.)
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
– Excessive Fuel Consumption
P0172 GMC OBD Code Description