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GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15201
Experience:  GM Grand Master Technician 2007. 14 years experience.
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2002chev avalanche 1500 Z71 engine code PO171 reads

Customer Question

2002chev avalanche 1500 Z71 engine code PO171 reads out...what .does this mean
Submitted: 1 year ago.
Category: Chevy
Expert:  camerontech replied 1 year ago.

hi there,

im cam, a licenced diagnostic tech.

p0171 is a "Bank 1 fuel system lean"

This means that your 1 side of the engine is running lean.

the fuel trims and oxygen sensors will have to be checked.

possible problems that are associated with this code are:

1.intake manifold gasket

if the intake manifold gasket is leaking, this will draw in air and cause a lean running bank. the gasket would have to be replaced.

2. oxygen sensor

IF the oxygen sensor is lazy or faulty, this will give a false lean code as the sensor cannot monitor the fuel trims.

3. plugged fuel injectors.

if the injectors are plugging up, a bad spray will cause a lean condition. they will have to be cleaned or replaced.

.

these are the most common areas of this code.

since it is only one bank that is lean, it is unlikely that it is a mass airflow sensor.

your mechanic will be able to runa diagnostic test and compare both banks and pinpoint why your engine is running lean on 1 side.

If you need any more assistance id be happy to help

let me know what you find!

Customer: replied 1 year ago.
ok thank you much Cameron