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ironmike
ironmike, ASE Master Technician & T2 diesel
Category: Cadillac
Satisfied Customers: 3385
Experience:  30 years experience foreign and domestic, GM certified
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Po 171 po 174 keeps setting code what does this code mean

Customer Question

po 171 po 174 keeps setting code what does this code mean
Submitted: 6 years ago.
Category: Cadillac
Expert:  ironmike replied 6 years ago.

greetings,

did you check for vacuum leaks? did you check fuel pressure? theses generally point to a lean condition

Customer: replied 6 years ago.
yes no apparent vacumn leaks fuel pressure okay
Expert:  David H replied 6 years ago.
The common cause of that is a split intake manifold plenum boot .This vacuum leak is hard to find because of it's location.This boot requires removing the intake manifold to replace.This boot goes bad on all these models at one point or another.

Edited by David H on 7/7/2010 at 3:15 AM EST
Expert:  ironmike replied 6 years ago.

greetings,

Check the intake manifold plenum boot. These can leak and are hard to find.

The intake manifold has to be removed to access the plenum duct/hose, with this repair you will replace the intake gaskets also. This is a 2-3 hr job.

good luck

ironmike, ASE Master Technician & T2 diesel
Category: Cadillac
Satisfied Customers: 3385
Experience: 30 years experience foreign and domestic, GM certified
ironmike and other Cadillac Specialists are ready to help you
Expert:  ironmike replied 6 years ago.

here is a picture of the location

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