99 Protege with P0171 Code - Mazda Forum - Mazda Enthusiast Forums

Mazda Protege This compact model offers an economical solution for the need for a sporty sedan or wagon.

Thread Tools Search this Thread
Old 04-15-2010, 03:09 PM
Thread Starter
Join Date: Nov 2008
Location: San Diego, CA
Posts: 98
Default 99 Protege with P0171 Code

I got this code from my check engine light, and after what I found in the internet there are a lot of possible cause it seems. Here is what I found.

The following is an overview of P0171 check engine light code possible causes.
Fuel System:
Leaking or faulty fuel pressure regulator
Plugged or dirty fuel filter or lines
Fuel pump weak or defective check valve
Injectors leaking or faulty
Low fuel pressure or running out of fuel
Leaking EVAP system components
Faulty FRP (Fuel Rail Pressure Sensor)

Air Intake System:
Vacuum leaks
Contaminated, damaged or faulty Mass Air Flow sensor
PCV valve leak or stuck open
Air induction turbulance caused by wrong filter
Oil dipstick not seated
Air leaks after the Mass Air Flow Sensor (MAF)
Oil coated aftermarket air filter

Exhaust System:
Any exhaust leak before or near the oxygen sensors

EGR System:
Vacuum line disconnected from EGR System Module (ESM)
EGR valve, tube or gasket leak
EGR vacuum regulator valve leaking

Secondary Air Injection System:
Mechanically stuck secondary air injection valve

What I do know what is not the cause are these:
-MAF been replaces just about 1 year ago by my Mazda dealer and they clean the air intake area as well. So is not that.
-PCV valve been replaced by me also about 1 year ago and I checked too...no leak there.
-Also just passed smog check a week before this check engine light turns on. So not the exhaust.
-Oil dip stick is fine.
-Also just used one of those Lucas fuel injection cleaner for the tank of gas before the engine light turn on. Most likely not the fuel injection system.
-I know my 99 protege has no fuel filter according to mazda dealer, so can it be the fuel line?

All that is left for me almost sounds like only the EGR system left to check. The thing is, my car still drive like normal, nothing seems to be wrong, and gas mileage also normal, in fact is slightly better than what I normally get after I used the Lucas fuel injection cleaner. Only thing I notice in my engine compartment is low in radiator coolant level in the reserve tank not in the radiator or air filter is a little dirty. But air filter been dirty before in the pass and never trigger check engine light. Also, I wouldn't think radiator coolant level has to do with this code. So any idea or insight of what it might be would be very much appreciated. I am on the verge of just bringing it in to a mechanic to diagnose what really is the cause. Been almost a week since I got this check engine light but did not feel anything unusual with the car that I drive everyday. Thanks in advance.
Reply With Quote
Old 04-17-2010, 12:17 AM
Senior Member
Join Date: Jun 2008
Location: central new york
Posts: 146

P0171 on 2001 protege W/2.0 L ended up being a rip in the seam of the intake hose. Drove me bonkers trying to find the prob. When the engine idles, everything fine. When accelerating, the engine torques and the unseen rip in the intake hose opens, sending way more air to engine than what the MAF told the ECM . long story,but easy fix
(if thats problem).......replace in air metering hose from air box to intake manifold
Reply With Quote
Old 04-28-2010, 07:52 PM
Junior Member
Join Date: Apr 2010
Location: Midland MI
Posts: 2
Cool P0171 code

My 02 same problem I found the cracks in the ribs of the air tube by running my fingers around the air tube. I have sealed the tube until I find one. The R&R is very easy.
Reply With Quote
Old 01-12-2013, 01:34 AM
Junior Member
Join Date: Jan 2013
Posts: 20

I still have the problem ... the MAF sensor , O2 sensor is new and I don`t know what the problem is ....
Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
HELP! 2006 Mazda Tribute 4cl P0171 Code meme2005 Mazda Tribute 6 02-10-2013 06:56 AM
Help! P0171 - Engine Code YmeHP Mazda Protege 2 03-06-2011 05:27 PM
626 Code P0171 - System Too Lean (Bank 1) chitowntommy Mazda 323,Mazda 626 & Mazda 929 6 01-13-2008 10:21 PM
CEL Code P0171 followed by 0174 and 481 on 2001 MPV osbormd Mazda MPV 3 09-12-2007 12:23 PM
Code P0171 - System Too Lean (Bank 1) rpgrayso Mazda Protege 3 08-22-2006 06:21 PM

01, 1999, 99, check, cleaning, code, engine, filter, fuel, injection, light, located, lx, maf, mazda, p0171, protege

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -5. The time now is 09:07 PM.