Had error code p0171 a 6 weeks ago and the auto shop replaced the MAF sensor. The engine light came on again and now reports p0171 and p0174. The car is seldom driven and has maybe 300 miles on it since the MAF was replaced. I read your article, but how should I proceed?
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2003 Chevrolet Suburban 1500 Question: I have OBD error code p0171/p0174
Answer #1patrick mannion from Greg Solow's Engine Room, January 23, 2012, 21:15Master
Both codes are fuel trim fuel control related. I would start by looking at sensor values and fuel trim figures an a professional grade scan tool it saves doing intrusive testing at each individual sensor. There is a professional service called Identafix. http://www.identifix.com/info/about_us.htm They only deal with professional repair shops. They are in the Minnesota 651-633-8007 begin_of_the_skype_highlighting 651-633-8007 end_of_the_skype_highlighting. Your auto repair shop do all their diagnosis tests, and discuss your problem with a team of professional technicians great service cheap and very bright people. If the repair shop that are repairing your car are stumped this is a great service. This company only deal with automotive repair shops and don't answer questions for the general public but are an amazing knowledge base.