I am having a difficult time trying to fix my CEL issue, The vagcom scan says P0171 & P0174 Lean banks 1 and 2. I don't believe both O2's went out I have Checked and cleaned the MAF Sensor did a quick vacuum leak inspection and all seems good. I have a GIAC ST 1 and an AFE intake with noise pipe delete. I can reset it but it returns after a day or so.
View 1 RepliesI have been getting a P0171 and a P0174 code lean bank 1 and 2 sensor 2. I have replaced all 4 censers the 171 is gone but I keep getting the P0174 and it only comes on when I am on the highway after driving around 10 miles or so i got a freeze frame of the data when it happen.
View 6 RepliesI have a 99 f150 with the 4.2l v6 with a 5 speed 173000 miles. I picked it up not to long ago. When I first got it it had both the P0171 & P0174 lean on bank 1&2 it was also siting for a while. I replaced the fuel filter which was filled with black fuel, also changed the PCV valve, cleaned the MAF sensor, and changed the oil. I cleared the code, drove it for a little bit and the light came back on after 20 miles.
I then proceeded to replace the upper and lower intake manifold gaskets. Upon doing that i noticed that i was missing one of the linkages for the IMRC. I went to the junkyard and pulled off another linkage rod off the same motor. ordered new plastic clips, put the IMRC on cleaned everything up and began putting it back together. I also cleaned the Injectors while i had them out as well and put in new spark plugs and wires.
Put everything back together. code was cleared since the battery was disconnected. drove it and then the engine light came back on again. this time it was only the p0174. so i then both the upstream and downstream O2 sensors on bank 2, reset the code and it came back on again. I'm lost.
After installing Banks headers and full exhaust, I took my truck for another test drive this morning. SES light came on about 15 mins into drive and is telling me P0174 - Bank 2 Lean.
So that's the right/drivers side - my list of things to go check
O2 Sensor plug on that side
The MAF
The IAC
Vacuum lines ...
I have a P0171 code (lean bank 1 sensor 1) on my 2002 toyota camry 4 cylinder. I don't have any other codes except for an unrelated P1780 neutral safety switch code. It has had both codes for over a year.
I have replaced the fuel filter, the upstream o2 sensor, and the PCV valve. I also cleaned the MAF sensor. The mechanic performed a smoke test and found no vacuum leaks. Did a fuel pressure test and it's normal. Mechanic thought it would be fuel pressure because the car starts a bit slow when cold, but nope. The car runs great and still gets great gas mileage. I've never experienced a misfire in my 12 years of owning the car. I am asking because I am at a loss as to what it could be.
I recently had some work done on my 2001 VW Passat 1.8T (timing, water pump, major tune up). IT had 72K miles.....
Now I'm getting the following:
Code P0171 Too Lean (Bank 1).
Emission Light turns on / off.
Check engine light comes on and stays on after about 20 miles. Can this be the oxygen sensor?
2000... I have a code P0171 bank 1 too lean. My question is does this exclude anything that will effect both banks? If it was MAF sensor or fuel filter would it set code and say banks 1 and 2 running too lean? In which MAF sensor ohms out correctly. I cannot view fuel trim files. I have looked for a vacuum leak with no luck. I got some cigars to try to smoke it to see if there is any vacuum leaks. Trying to narrowing what i need to checks.
View 19 RepliesI have a 2006 Chevy Trailblazer LS/LT 4.2 liter 2wd. I have been trying to get it smoged, but can't clear the code. P0171 - Lean Bank 1.
I've been having a parts throwing contest with it, but it has been winning and my wallet is losing.
I have changed the air filter, cleaned the MAF sensor, changed both O2 sensors, changed the secondary air valve and relay. I've done the carb cleaner spray test around the intake and vacuum lines, with no spikes in RPM.
Most recent try was a couple bottles of Techron concentrate with premium chevron gas.(still waiting to see if the code hits again)
Next steps are checking the intake bolts(to see if they are torqued) and intake gaskets, check for exhaust leaks at the exhaust manifold, and checking the MAP sensor.
Freeze frame data from the most recent hit on the code is below.
***Fuel system 1 - CL***Fuel system 2 - NA***Calc Load(%) - 30.2***ECT(deg c) - 48***STFT B1(%) - 3.9***LTFT B1(%) - 22.7***MAP(kPa) - 33***Eng RPM - 809***Veh speed(km/h) - 0***Spark Adv (deg) - 10.5***IAT(deg c) - 20***MAF (G/s) - 5.82***TPS(%) - 15.3***Air status - NA.
We have a 2003 Passat 1.8t. Had the Check engine Light come on. Went down to AutoZone and hookeded up the OBDII reader. Came up with P0171, Fuel System for Bank 1 was too lean. Probable causes:
1. Fuel Pressure of MAF (If Bank 1 & Bank 2 set codes together)
2. O2 Sensor
3. Ignition Misfire
4. Fuel Injector Problem
Car has 60K - has always run well. Wife says she thinks it's running a bit sluggish. I rarely drive the car, but I think she's right. Car is not missing or running rough.
I cleared the code & started the engine; Check Engine Light is off; then looked at the codes and I find a P0171 (Pending). She tells me that the light has been on before & then gone away. So I guess it clears itself, but eventually comes back.
I just bought a 99 f150 and the check engine light came on with code p0171,system too lean bank 1. It runs and drives fine but has a strong smell of gas when I shut it off.
View 4 RepliesWorking on my son's 2001 sport trac. 200K miles but it has always been a great running truck.
I have two CEL codes:
P0171 System too Lean (Bank 1)
P0174 System too Lean (Bank 2)
I have found several issues so far, but have yet to get rid of these pesky codes.
So far I have changed:
- Intake Gasket - I had coolant loss which replacing this gasket fixed.
- PCV Valve and Hose - valve was damaged and the hose leaked.
- EGR Valve - Valve was leaking
- Fuel Filter
- Mass Airflow Sensor
The engine does appear to be running much smoother now, but the lean codes remain.
2003 Sport Trac. My car was not starting, told my fuel pump, replaced twice and nothing. Found out about inertia switch and changed it, now car runs.
Before this switch blew out my car was running perfectly, no check engine, nothing. Now i have changed my fuel pump twice and put a brand new fuel filter in and soon after i get lean codes P0171 and P0174. My fuel pressure is 60psi at idle and drops to 0 after about 30 seconds when the car is shut off.
A lot of my intake is new since i did have a vacuum leak before, so i do not suspect that is it, especially since this happened after the new fuel pump. I am completely stuck as to what i should do. And i get hesitation when trying to accelerate sometimes
97 F150 4.6 200xxx on recent rebuild. My truck is throwing P0171 & P0174.
I think I tracked it down to leaky IAC and EGR gasket. I sprayed both with carb cleaner and the RPM's dropped.
My question is, wouldn't the RPM's rise instead of drop? I was under the impression that they would go up if the gaskets were leaking. Or did I use the wrong spray?
I had my fuel system cleaned by the dealership last weekend and I feel like I gained 50hp+ ... Now its throwing a P0171 about a week and a half later. My computer also listed P0174 under the pending codes or whatever the section was.
2003 F150 5.4L ... I cleaned the MAF sensor a couple weeks back which stopped a rough idle and I have put some 300+ miles on it since. about 200 miles since the fuel system cleaning.
I got home and popped the hood and it sounded like a vacuum cleaner. Guess it is a vacuum leak. I might need to stop using this ford house. I swear this is the second time there was a vacuum leak(I think, first time they said it was spark gap issue). I'll be heading back in the morning now.
P0306 (ok #6 missfire) with P0171 & P0174 --- Do I chase electrical or fuel or both. Afraid to assume anything but probably would normally address the misfire electrical first.... Don't want to go down that 'primrose path' if others have been there first!
View 4 RepliesI have a 2002 prius with 130,000 miles on her, and so far so good except for a small problem for the last three months, I get an intermittent P0171 code. I know it means Lean Condition in Bank 1. However, I can run the car for weeks without it coming on. If I go full throttle getting onto the highway for example it may come on, but even then its not all the time. Not sure why only full throttle. But if I drive her gently, I will never see the CEL at all.
Fuel economy is around the usual for me at 46-49 mpg with average speeds of 75-85 mph. I don't think its vacuum related.
Well I got the ubiquitous "Bank 1 Too Lean" code this morning. Yesterday I changed out the PVC Valve, Elbow and Hose assy.
I changed out the hose from the intake to the canister purge valve on the firewall next to the master brake cylinder, that one was like dust.
Today I'm changing out the rear O2 sensors, but I may change out the fronts when they get them in (very rural area hear).
I'll keep looking for vacuum leaks and change out the MAF sensor. I hate to think it may be the intake....
I have a 2001 Passat 1.8T that has the pesky MIL light on with a DTC code P0171 lean system. I have sent it to the mechanic many times to no avail. What the mechanic did was replacement of the MAF, O2 sensors, checked intake manifold leak as well as exhaust manifold leak. His last attempt was to check for clogged injectors and fuel filter and they were in good condition. He says the ECM is bad. I was able to retrieve freeze frame data as well as live data which shows that the computer is compensating what it thought was lean by having very positive LTFT of 22.6. I don't believe the ECM is bad but cannot be sure. There is one more thing that was not checked by the mechanic is the EGR valve. Could that be the cause of my woes - the lean system?
View 14 RepliesI have an 07 passat with a 2.0 4 cyl turbo and I have an error code of P0171 system too lean (bank1) but engine seems to run just fine, what this code means, am wondering if it is something I can fix or if it needs to go to the shop??
View 2 RepliesI've searched for this and haven't come up with much other than the same error code for a bunch of other vehicles, and a bunch of different responses. My Tacoma is a 2000 PreRunner, 3.4 liter engine.
The exact code I get it is:
P1071
bank 1 system too lean
What this could be?
Wife took truck out and turned around after going less then a mile, saying it was running very bad. We got this truck about two months ago at a state vehicle auction. It was a state used truck, 145,000 miles, 05 Ford F350, ext cab and 8' bed. Anyway at first I thought it was valve tap until research said an exhaust manifold. With a fog machine in rear exhaust pipe we confirmed it was leaking and replaced the exhaust manifold. Figured it was probably a good time to replace spark plugs too. Took truck for a ride and she still buck and farted.
Got a code machine and got P0171 and P0174. Couldn't find a vacuum leak, but your could hear the air being sucked in. went to local parts store, guys couldn't find leak, but they said truck sounded like a steam machine. today I made a homemade smoke machine and smoke came from air intake, figured the gaskets were bad. The pictures show what I saw when I took the gaskets off. The port that has melted is the same port were the exhaust manifold was leaking from. Am in deep "doo-doo". What caused this?