Help with Codes
Thread Starter
Teching In
Joined: Nov 2005
Posts: 40
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Help with Codes Ok, I went to Autozone and had them check my codes that are being thrown in my 2000 TA
PO171: Description: The PCM determined that during testing, the fuel system for bank 1 was too lean
PO174: Description: The PCM determined that during testing, the fuel system for Bank 2 was too lean
PO420: The PCM has determined that the catalyst system efficiency for bank 1 is below threshold for the current engine operating conditions. (O2 Sensor?)
PO430: The PCM has determined that the catalyst system efficiency for bank 2 is below threshold for the current engine operating conditions. (O2 Sensor?)
How do I fix the first 2 codes? Do I need new fuel injectors? Or have something done with the PCM?
How do I fix the other o2 codes? Should I replace all of the sensors? or start out replacing one at a time?
Thanks for the input
PO171: Description: The PCM determined that during testing, the fuel system for bank 1 was too lean
PO174: Description: The PCM determined that during testing, the fuel system for Bank 2 was too lean
PO420: The PCM has determined that the catalyst system efficiency for bank 1 is below threshold for the current engine operating conditions. (O2 Sensor?)
PO430: The PCM has determined that the catalyst system efficiency for bank 2 is below threshold for the current engine operating conditions. (O2 Sensor?)
How do I fix the first 2 codes? Do I need new fuel injectors? Or have something done with the PCM?
How do I fix the other o2 codes? Should I replace all of the sensors? or start out replacing one at a time?
Thanks for the input
TECH Addict
Joined: Nov 2001
Posts: 2,003
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From: Live Oak, FL - in the woods where the creatures lurk.
With both P0171 & P0174 set it could be a vacuum leak.
If you can eliminate that, you'll need to probably
check out the fuel system itself.
If the engine has been worked on recently double check
all wiring connectors, vacuum lines, etc.
With the cat converter codes set also you may want
to check that end out first. Not sure if the cats
being clogged (if they are) will affect how the computer
adds fueling.
Might want to find a good mechanic to make a diagnosis.
If you can eliminate that, you'll need to probably
check out the fuel system itself.
If the engine has been worked on recently double check
all wiring connectors, vacuum lines, etc.
With the cat converter codes set also you may want
to check that end out first. Not sure if the cats
being clogged (if they are) will affect how the computer
adds fueling.
Might want to find a good mechanic to make a diagnosis.
Teching In
Joined: Sep 2005
Posts: 8
Likes: 0
The efficiency codes are just that....your cats are done, however there is a small chance that if you correct the lean condition the cat efficiency test will pass on the next completed drive cycle...as the pcm monitors upstream o2's and downstreram o2's to determine the efficiency of the cats. Most common cause of p0171 & p0174 is a vacuum leak...can be tough to find...a smoke machine makes it very easy.
Bottom line; if you don't have all the neccessary tools you may spend a lot on parts because you'll be guessing, however spending $70-$100 for a professional diagnosis could save you in the long run...just make sure whomever you choose is indeed professional. If you don't have a trusted technician, you might try Car Talk website for customer recommendations, searchable by geographic location.
HTH
Bottom line; if you don't have all the neccessary tools you may spend a lot on parts because you'll be guessing, however spending $70-$100 for a professional diagnosis could save you in the long run...just make sure whomever you choose is indeed professional. If you don't have a trusted technician, you might try Car Talk website for customer recommendations, searchable by geographic location.
HTH
