2006 Chevrolet Trailblazer P0171 Diagnostics

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www.wellsve.com/ When the Dealership runs out of guesses and you are running out of money to get the check engine light to go "out" who do you call? Call Inspector Tech! This video is a great demonstration of diagnostic brain power, we hope you enjoy it!
The information presented in this program is based on a specific diagnostic case and might not directly apply to the vehicle you are repairing. We do not represent or warrant that the information presented is complete or error free. Please take all safety precautions. We disclaim any and all liability for losses, injuries or damages in connection with your repair.

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16 фев 2012

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Комментарии : 130

@ryansauto93 12 лет назад

Awesome video! I love that you are promoting the diagnosis and evidence gathering portion of auto repair, not just throwing parts at the car and wasting time and money.

@dmorley100 12 лет назад

WOW!!!!! Very good job on this video. This's truly an off-the-beaten-path diagnosis for a common DTC. My hat goes off to you.

@dtensign8329 6 лет назад

Thanks, Had this 171 fault on my 2007 Trailblazer, Replaced the valve for a part cost of $118. Would have never thought that was the problem.

@GoTechTraining 6 лет назад

Great DT Ensign, the video did it's job then! :) Mike Becker, Senior Technical Services Instructor

@ResonantEcho0 7 лет назад

Just bought a 2006 Chevy Equniox - P0171 code. The vehicle drives fine for a period of time during the day then, will choke and die repeatedly, typically when coming to a stop but will also cut out / stumble while driving too. The car has 97k miles, so I just completed a few maintenance items including plugs & wires, cleaning the MAF and replaced a broken canister purge valve solenoid. When the issue persisted, I suspected the EGR of causing the problem and replaced this as well. After watching your video, I'm now considering the air injection valve.

@PackedFunk 11 лет назад

Thank you Mark for all your help.

@hijitus99 4 года назад

Thank you for this phenomenal video, it's bringing some light at the end of my tunnel. Question: if the issue was the SAI solenoid, why a more specific code to that part was not reported, like P1413, for example??? Thank you, Horacio

@Supermonkey1417 2 года назад

Great video I have a envoy with the code p0171 first I going to check for any intake leaks, but how can I check the valve before I replace?

@GoTechTraining 10 лет назад

Good question ... I looked on AllData and the information was vague. It gave only the replacement times and the vacuum diagram said if it is supplied. I then looked on Identifix and they did not list anything. My guess is that you don't have an A.I.R. system. Mark Hicks Wells Vehicle Electronics

@jaydesmith6887 7 лет назад

I have a 2004 trailblazer i6 ... its been having a real rough idle in drive at a stop light or stop sign. I changed the cam position sensor and vvt after I got the code for cam sensor. p0340 ... ran good on the initial test drive. turn the car off, and when i restart it starts shaking again. Any ideas? Its not a vac leak, not spark plugs not the coils not the map sensor... My water pump is showing signs of it about to go out... Please any help would be awesome I'm broke and in school and doing repairs on my own.

@smoothbcuz 8 лет назад

hey Mike thanks for the response. I have an 03 trailblazer ls 4.2 I did some searching and found the code could be thrown if there is an exhaust leak near the o2. I have uwt to check bit maybe I didn't tighten the bolts enough when I replaced the cat.

@GoTechTraining 8 лет назад

Hey Rob, yes that can cause it. Basically that code is set saying there is too much oxygen in the system. More than there should be. The computer is compensating by adding more fuel. So you will see a decreased fuel economy. Now this is determined by the oxygen sensor. So you are completely right that leaking exhaust can cause this. Other common things are bad vacuum hoses, leaky intake gaskets, and secondary air injection systems not functioning right. First thing I would look at is leaky exhaust being that there was just work done there. Hope this helps! Mike Becker, Technical Services Instructor

@SteveRobReviews 12 лет назад

Fantastic!! Always look forward to your videos. Most of your diagnostics is related to previous shops misdiagnosing a system error. It would me nice to hear your thought on why the techs are missing the evidence on a video. Lack of knowledge or lack of testing equipment or guessing and throwing on parts at customers expense. If the repair shops do not get up to speed they will most likely bring everybody down with them .

@jasonmoriset9292 10 лет назад

This video definitely connects with the problem I'm trying to remedy. I also get a code for P0496 Secondary Air Injection system. Could these both be tied together or would I be looking to replace purge and vent solenoids on the SAI system in the rear as well as the shutoff valve you diagnosed?

@GoTechTraining 12 лет назад

Thank you for the kind words. Vacuum leak was my first thought also. However, it wasn't just that the engine was running well, it was also that the fuel trims went right back into normal ranges after the problem occurred. We really had no evidence to make us think something was wrong with the engine. Thanks for the great comment! Mark Hicks Wells Vehicle Electronics

@GoTechTraining 11 лет назад

Excellent! Thanks for the update. I always liked FelPro too. Take Care, Mark Hicks Wells Vehicle Electronics

@paulhawkins1460 2 года назад

I have a 2006, and I am experiencing the same thing. I have changed both o2 sensors, air filter, MAF sensor, intake manifold and throttle body gaskets, and Catalytic converter. Still getting same code. I'm wondering if I have the same issue.

@SEXYTECH1000 11 лет назад

THIS GUY IS A TRUE TECH!!!!!EXCELLANT DIAGNOSIS,,,,,

@PackedFunk 11 лет назад

Hi Mark. I have a 2000 Silverado 5.3 with the dreaded P0171 code. Have replaced MAFS, fuel filter, cleaned air filter. Spraying carb cleaned around intake makes no difference in idle speed at all so I don't think intake gaskets are bad. After reset I still get P0171. Any help is apreciated.

@snaponjohn100 12 лет назад

Great video. Thanks for posting. God bless. John

@GoTechTraining 11 лет назад

Sounds like it could be running lean to me. Have you checked the fuel pressure? Mark Hicks Wells Vehicle Electronics

@merriman420 10 лет назад

Very helpful. I also have a problem where I feel shaking at idle in drive until the truck warms, then the shaking subsides. With colder weather in effect, this is getting worse. Any relation to this? Or seperate occurance? In Park, or neutral, the shaking stops. Thank you

@GoTechTraining 10 лет назад

Probably not related to this problem. Give me the year, make, model and engine size of your vehicle and I will try to help you pin down the cause. Mark Hicks Wells Vehicle Electronics

@carlbrooks90 6 лет назад

Angel Pacheco you could have carbon build up. Try taking it to bg 44k for a fuel introduction service.

@felplayvina 12 лет назад

I Mark, question about 97 chevy s10 fire order bottom coil is 1 4 top 2 3 the fire order is 1342 this will be start from the fire wall or front engine?

@FernandoGarcia-bu2nj 10 месяцев назад

I have a 2006 trailblazer LT V6 4.2. I've changed out many parts... Throttle body...both 02 sensors...MAFS.. IT manifold gaskets...2nd air intake sensor...plugs..gas cap... purge valve...Air filter.(vehicle runs and idles great) Keep getting P0171...Noticed it comes on when idling...Also when engine up to temp...I reset code and comes right back on...Any advice? Thanks!

@jaimesalazar4062 7 лет назад

I have a 2008 Silverado, I had a P0121 code come up so i washed my K&N filter/ MAF/ and my throttle body(did not remove the TB). It was a pain in the rear to re-program the throttle body but i think i got it. The next day i get this P0171 code! I checked the Vaccum hoses and i had 2 fitting cracked. So i replaced the, still nothing. The same code keeps coming up. Does my truck have one of these? If so is it the "Canister Vent Valve Solenoid"? As soon as that code comes up on my UltraGauge my "Service Stabilitrack" light comes on and the truck shifts hard. I want to fix this before i need to rebuild my transmission.

@GoTechTraining 7 лет назад

A P0171 means that for whatever reason your engine is running lean. There are a ton of things that could cause this. Do you have a full function scan tool that you can look at engine data with? Mike Becker, Technical Services Instructor

@GoTechTraining 10 лет назад

Gracias por su solicitud. Estamos trabajando en hacer más videos en Inglés y Español. También estamos trabajando para hacer transmisiones en vivo en español y en Inglés. Cuando empezamos a hacer esto vamos a anunciar en RU-vid. Si usted no está suscrito, por favor, y luego se le notificará. Mark Hicks Wells Vehicle Electronics

@GoTechTraining 11 лет назад

Thank you for the kind words! Means a lot to us. Mark Hicks Wells Vehicle Electronics

@GoTechTraining 12 лет назад

@dmorley100 Thank you my friend! Glad you liked it. The real hero here is Inspector tech (Jim Gehl), he is the guy who figured it out! Very good tech who works in our department. Mark Hicks Wells Vehicle Electronics

@raultopete5728 2 года назад

Would the faulty air solenoid cause a rough/stall start?

@richardbrice4553 3 года назад

Could this air solenoid control shut off valve be called something else,I can't find I'd anywhere

@spelunkerd 12 лет назад

Great review.

@GoTechTraining 12 лет назад

It comes down to time available. As you can see we do all of our own video work. This means everything from shooting, script and editing. We do this in between tech line assistance calls. Plus we do all the training and give customer service and engineering support. I really wish we could, maybe someday. Thank you for the great compliment, it truly means a lot to me! Take Care, Mark Hicks Wells Vehicle Electronics

@woog74 12 лет назад

I concur with many other, fantastic tip/lesson in this video. I had a question. At about 5:30 in the video, the conclusion is drawn that there is nothing wrong with the motor itself causing this lean setting, with the reasoning being that the engine performs well. Specifically ruling out vacuum leaks, which was my initial speculation. My question is, couldn't the PCM have added enough fuel to compensate for the vacuum leak so that you would not notice it while operating the vehicle?

@ragz247 10 лет назад

I have a 2003 Chevy Tahoe 4.8 do I also have a secondary a.i.r. system?

@lassiejr2115 4 месяца назад

Im having same issues with my 2002 Trailblazer but I don't think it has that part , what other part might be on the 2002 Trailbalzer ?

@PackedFunk 11 лет назад

Does my 2000 silverado 5.3 have a a.i.r. System?

@meanf1502 6 лет назад

I have the same yr an motor my engine light is on an the auto shop said motor is lean tilt steering wheel senor any ideas

@GoTechTraining 6 лет назад

Hey Super Chevy, not sure exactly what you are getting at here. The engine is running lean? What does that have to do with a steering sensor? I'm confused. Can you clarify please. Mike Becker, Technical Services Instructor

@carmenalvarado3684 6 лет назад

I have a 2006 chevy trailblazer EXT LS/LT 4WD and it's happening the same as @Angel Pacheco it's shaking a lot and when i pump gas it's hard to make the engine start

@GoTechTraining 6 лет назад

Hi Carmen, if the evap purge solenoid is stuck open then when you fill with gas it could be forcing vapors into your engine and causing a rich condition. Is the check engine light on? Mike Becker, Technical Services Instructor

@carmenalvarado3684 6 лет назад

No not at all but i buy it from someone else and i guess they fix everything because they even cover the odometer so good that it's 310k miles

@woog74 12 лет назад

Thank you Mark. That compliment means a lot coming from a diagnostician of your caliber. How come Wells does not produce a video series for sale? There is very little furthering education on the technicial diagnostics for an independent. After watching your youtube videos for the past 6 months or so, I would not hesitate to purchase a educational videos from Wells.

@snoopdog6793 6 лет назад

Hi. I have a 2006 gmc envoy with 4.2 engine. I keep having p0171 code and its burning alot of fuel. At idle the short term stays around 2 and long term around 13 or 14. If i give it gas the short term goes to negative and the long term goes to 4 or 5. I already replaced the maf sensor and both oxygen sensors.

@GoTechTraining 6 лет назад

Hey John, what about vacuum leaks? Have you inspected for that? A P0171 is a lean code, meaning there is excessive oxygen being read by the O2 sensors. Mike Becker, Senior Technical Services Instructor

@snoopdog6793 6 лет назад

Wells Vehicle Electronics i actually had a independent shop smoke it and check fuel pressure and the fuel was in specs and they couldnt find any leaks. The long term fuel trim is above 18 at idle. The fuel trims are at specs when the truck is cold.

@richardbeckmann3782 10 лет назад

Thank You!

@YH7R Год назад

Great detailed content GOD BLESS

@GoTechTraining Год назад

Thank you kindly! Glad you enjoyed the video! ~Ryan

@YH7R Год назад

Yes I also subscribed really enjoyed thanks again

@GoTechTraining Год назад

Thanks for the support! ~Ryan

@dmorley100 12 лет назад

Finally you got this put up. I was beginning to wonder if you were yankin our chain as to whether this vehicle actually existed or not, LOL.

@GoTechTraining 10 лет назад

Run water on the intake manifold, check for vacuum leaks. The most common cause for these codes on your vehicle is leaking (vacuum) intake manifold gaskets. When your intake brings air into the engine that is not metered by the MAF it will run lean. The less air the MAF reads equals less fuel which equals lean. Check the intake manifold gaskets. Mark Hicks Wells Vehicle Electronics

@GoTechTraining 11 лет назад

Sorry to hear you still have the P0171 code. Yes, your vehicle does have an A.I.R. system. Try disconnecting the pump located at the right rear of the engine compartment near the front of the dash. Clear the code and see if it returns. Mark Hicks Wells Vehicle Electronics

@smoothbcuz 8 лет назад

I just replaced my catalytic converter due to po141 code. upon completion and test drive this po171 came up this code was present previously. also I did replace o2 sensor after cat due to not being able to take the old one out. and its a bosch not ac delco. is this possibly my issue. please help my inspection end of the month this is my only form of transportation.

@GoTechTraining 8 лет назад

Hi Rob, a p0141 is related to the oxygen heater circuit. Sorry to hear you had to put a catalytic convertor in because you couldn't separate the 02 from the cat. That's no fun. Now as for the P0171, that means your vehicle is running lean. It is possible that because the computer had the P0141 code it never ran the test on the P0171. So after you fixed the P0141 problem. The test for P0171 ran and failed. What kind of car are you working on? I'll do some digging and see what is common to a P0171 on your car. Mike Becker, Technical Services Instructor

@22752 3 года назад

I have this same code on my 2005 Chevrolet trailblazer 4.2.....car wont crank only if I have it off for a hour or more. Plz help

@lukef9362 10 лет назад

i have a 2007 trailblazer LS with the same code (p0171) but its also sending p0300. i cannot find the part anywhere and havent taken it to a shop. sometimes when i start the car, it will drop down to about 500 rpm's for maybe a second or two but then comes back up. it does that sometimes while idle in a cold start it will hold around 600-700 rpm's. i guess what i want to know is the second code the p0300 causing the p0171

@GoTechTraining 10 лет назад

Believe it or not, Yes the p0300 could be causing the P0171. I am going to assume you have a 4.2 Engine. It is known for the intake manifold to cause a vacuum leak causing a cylinder or two to run lean, misfire and in turn cause the lean code. Check the intake for vacuum leaks. Stay in touch, Mark Hicks Wells Vehicle Electronics

@Gen01Lee Год назад

I think this is the only thing I haven’t tried for the P0171 code. I’ve done cam sensor, MAF sensor, crank sensor, VVT solenoid, check for leaks, spark plugs, wires, air intake manifold gaskets, gas vapor box in the rear. My truck runs and drives fine but at startup I get a hiccup/drop in rpm’s for a second that’s when the code will come on. I get it to go through emissions by using high octane gas/additives, code will eventually come back on though.

@GoTechTraining 12 лет назад

I like the way you think! Mark Hicks Wells Vehicle Electronics

@foxdmulder 12 лет назад

@Bonfield2002 Its mainly due to lack of understanding varied manafacturers systems. Key training and study and fine tuning of diagnostic skills are paramount in understanding modern vehicle systems.

@jasonevans2368 10 лет назад

I just came across your post. I have a 06 trailblazer ls I have a rough idle. I cleaned the throttle body with battery disconnected also replaced the plugs with iridium plugs also replaced the cam position sensor. no codes just feel vibration at stop or park and some hesitation when first accelerating.

@GoTechTraining 10 лет назад

I will assume you have a 4.2 Engine. Try cleaning the Mass air Flow sensor next. Mark Hicks Wells Vehicle Electronics

@jasonevans2368 10 лет назад

Thanks... I was also leaning in the direction of a bad throtle body seal. Yes it is the 4.2 l-6

@GoTechTraining 10 лет назад

jason evans Normally just cleaning the throttle plate will clear up the problem if it is the cause. Mark Hicks Wells Vehicle Electronics

@jasonevans2368 10 лет назад

Thanks. I will look at the mass air sensor

@jasonevans2368 10 лет назад

jason evans thanks looks like a good cleaning to the maf sensor may have done the trick. I think im still going to remove those pos bosch plugs and go with the acdelco irradiums

@PackedFunk 11 лет назад

I cant believe it Mark but I have a p0171 again. I changed intake gaskets. & properly torqued, mafs, fuel filter, air filter. Also I swapped o2 sensors to opposite sides. Still p0171 only after 3 restarts. I was disappointed to see only one bolt in egr metal flexline. I am thinking a leak in egr or pcv line.

@AerialDomeVideography 7 лет назад

I have a gmc canyon i5 3.7 could the secondary air solenoid being stuck open cause a hard code p0171? if so how could I check it?

@GoTechTraining 7 лет назад

Jared, yes if your Canyon has secondary air injection then yes, it could be causing the problem. You could remove the valve and plug the hole on the engine and see if it gets better. Mike Becker, Technical Services Instructor

@AerialDomeVideography 7 лет назад

Wells Vehicle Electronics thank you for the input I will try this and I love the videos keep them up!!!

@GoTechTraining 7 лет назад

Thanks Jared, let me know if you need any more help! Mike Becker, Technical Services Instructor

@AerialDomeVideography 7 лет назад

Wells Vehicle Electronics I closed of the secondary intake and the engine seemed to be running better but gave me a hard code p2436 I assume because the o2 sensors weren't seeing the air from the AIR system I am going to do more testing after work if this works then you guys have been a big help

@GoTechTraining 7 лет назад

Great Jared, seems like you're getting to the bottom of it. All fixed up now? Mike Becker, Technical Services Instructor

@oibal60 7 лет назад

Well done.

@GoTechTraining 7 лет назад

Thanks Gerald! Mike Becker, Technical Services Instructor

@woog74 12 лет назад

Mark would you have an email I could contact you at to ask an automotive question unrelated to this video?

@ragz247 10 лет назад

So after dealing with my P0171, P0174, P0303 (fixed) P0420 (fixed) for a year now. I said ok I nobody can figure out my P0171 and P0174 I am taking it to the dealership they did fuel pressure test and a vacum test. All came out good. They said the problem was the MAF sensor. I let them know I replaced it earlier this year, so I went to auto zone and replaced it and I still am getting a P0171 and P0174. I have replaced all four, 02 sensors and both catalytic converters. I have no idea what to do.

@ScatteredYO 2 года назад

I know you posted this back in 2014, so I hope you still check this RU-vid. Have you ever found out your real problem and a fix for it? Just bought '06 as a beater and it's having this P0171 as well at every second start or so. Sometimes it comes on in the middle of a drive. Sometimes it comes in when I start the car. I do not feel any different with or without the code, though. No rough idling, RPM surge, or anything like that. I do see the component name listed above my exhaust. The part, assuming is the correct part, costs anywhere between $110 and $190 (depending on model or brand). Anyway, I hope to hear from you regarding your case and how you ever had it fixed. Thanks!

@woog74 12 лет назад

I also noted another common denominator in the datastreams in the snapshot, was that both times the behcile was at rest. IE Vehicle speed 0. This made me think it was some kind of self test being run, particularly when it was at the 8 minute mark, and as I stated in my other comment, I was guessing some kind of vacuum leak from an electric valve. I was guessing purge solenoid. I didn't think to look, at how much fuel was in the tank at the time during the datastream snapshot, but should have.

@PackedFunk 11 лет назад

Well I finally changed the intake gaskets & everythings seems to be fine now. Used Felpro Gaskets from Oreillys 39.00 dollars. I always liked Felpro.

@jasonevans2368 10 лет назад

I'm still having the same problem with rough idle and hesitant acceleration. Still no codes. I've read an article that motor mounts may be an issue in this case causing the vehicle to feel like it has a rough idle. I have noticed some role in the motor when vehicle is in gear and you mash the gas there's probably a 1 to 1&a half inch roll. It doesn't seem like a lot of play but I'm not sure how much give there should actually be in these mounts.

@GoTechTraining 10 лет назад

It is tough to tell how much is too much movement when it comes to motor mounts. Unless it is completely out. It is even tougher to tell you what you are seeing is OK or not. What is the year, make, model and engine size? I can check the probability. Mark Hicks Wells Vehicle Electronics

@jasonevans2368 10 лет назад

2006 4.2 i-6

@GoTechTraining 10 лет назад

jason evans It is common for weak motor mounts to cause a vibration on your vehicle when put into drive. Recommended to use OE mounts if you are replacing them. Have you tried cleaning the throttle body? Mark Hicks Wells Vehicle Electronics

@jasonevans2368 10 лет назад

Yes cleaned throttle body, maf, replaced air filter, and delco iradium plugs disconnected bat to reset system. Im going to try replacing the vacuum hose going behind passenger side of engine compartment wondering if theres a leak. Also the mounts. Any other suggestions are welcome. Otherwise I Will let you know the verdict.

@GoTechTraining 10 лет назад

There is also a PCM re-flash for correcting the problem that is pretty common. Stay in touch, Mark Hicks Wells Vehicle Electronics

@jamesford8952 10 лет назад

amigo saludos, un fabor podria realizar mas videos de diagnostico en español

@aarongreen8627 7 лет назад

question, mine is a 2006 Chevrolet trailblazer and it doesn't even have that part, only a gasket and a little flat piece. So are you sure it's a 2006?

@GoTechTraining 7 лет назад

Hey Aaron, the Trailblazers came in 2 different configurations. The secondary air injection system came with the California emission vehicles. The federal emission models came with a plate covering the hole. I'd say it is safe to assume your's is the federal emissions. What's going on with it? I'd be happy to help. Mike Becker, Technical Services Instructor

@aarongreen8627 7 лет назад

it's been giving me codes every since i got it 5 1/2 years ago and most recently the PO171 code and the code just went away along with a soft ticking noise, i recently dropped the fuel tank to change the fuel pumpand got a 491 then a 446 code but they went away also

@GoTechTraining 7 лет назад

Intake manifold gaskets are quite common on these motors. I would inspect those. Mike Becker, Technical Services Instructor

@raziela5225 8 лет назад

disculpe. podrian poner este video en español. gracias

@angelf9800 3 года назад

Can this set a lean code p0171

@GoTechTraining 3 года назад

Hey Angel, yeh secondary air injection can cause a P0171. Mike Becker, Senior Instructor

@ProjectCarTV 2 года назад

Nice

@smoothbcuz 8 лет назад

po171 was not present prior to replacing cat

@merriman420 10 лет назад

Same as video. 06 Chevy trailblazer, 4.2l i6

@terrellscaife2411 Год назад

What about the 2003 version he doesn’t have one of those

@jasonmoriset9292 10 лет назад

Also, what if my truck DOESN'T have one? It is definitely a 2006 Trailblazer EXT with the 4.2

@aarongreen8627 7 лет назад

Jason Moriset mine is a 06 also and i don't have that part, i think it's really a 04 or 05 trailblazer and i just ordered the part for nothing.

@damanyocum211 4 года назад

Gentlemen, I have a 2006 Chevy Trailblazer LS with 4.2L with 4WD and around 73K on the clock-I need to pick your brains, guys-I've been dealing with a stubborn lone P0171 code for a while now-comes on unexpectedly-sometimes after 2 startups, sometimes after 6 startups-no stalling or hesitation, just the occasional lurch, then the MIL comes on I have smoked it, checked the fuel pressure, replaced both O2 sensors, MAF sensor, air intake tube, the secondary air pump valve, spark plugs and have performed a vacuum test and fuel pressure test-vacuum test results are in spec, fuel pressure is 58 psi key on engine off, 61 psi key on engine on-ran both at idle and at around 2500 rpm with no change-shut it down and the pressure drops to 57-58 psi sitting-I'm about ready to tear out the fuel pump and replace it along with the fuel pressure regulator-any thoughts? Many thanks!

@GoTechTraining 4 года назад

Hey Daman, have you taken a look at the purge solenoid? May be worth making sure it's sealed when there's no power and ground applied to it. Mike Becker, Senior Instructor

@damanyocum211 4 года назад

@@GoTechTraining I understand sir-where would the purge solenoid be located at? The P0171 is the only code showing, no other codes with it. I'm trying to find the solenoid here at home (I am a auto tech but I only work weekends since I'm going to school for my 2 year degree in Auto Technology) and I don't have access to ALLDATA or Mitchell at work or here at home readily. I have replaced also if I didn't mention it, along with the parts earlier listed, the vapor canister vent valve because when I smoked the exhaust system I saw smoke coming out of the two side vents of it, but I have not looked into the purge solenoid-my problem is that the STFT and the LTFT, when I see the freeze frame of the last MIL illumination, which was yesterday, it showed the STFT at 7.0 and the LTFT are at 24.2, ETC is at 203, MAP is at 13.0, VSS is at 0 MPH, SPARKADV is at 5, IAT is at 156 degrees, MAF is at 0.761 lb/min, and TP is at 16.5%, if any of that information helps.

@damanyocum211 4 года назад

@@GoTechTraining scratch my last on the location-I found where the purge solenoid is on the left side of the engine block-I purchased a new solenoid at AutoZone today-do you think this would affect the performance of the air/fuel ratio enough to show the off-kelter fuel trims that would cause the MIL on the Trailblazer-this vehicle belongs to my mom and her smog inspection is coming up next month (August 12th to be exact) so I am trying to get this thing smogged and fix this darn problem. Any thoughts are much appreciated!

@GoTechTraining 4 года назад

A truck open purge solenoid could definitively cause your issues. Good luck! Mike Becker, Senior Instructor

@damanyocum211 4 года назад

@@GoTechTraining Good day sir-I did get the purge solenoid installed and test drove today-was able to drive quite a distance before the MIL light came on...again-checked freeze frame data and saw the STFT and LTFT are a bit better-STFT at 3.1 and LTFT at 18.8, load is at 40%, fuel system 1 is closed, ETC 201 degrees, MAP 12.7 inches, RPM at 620, VSS at 0 mph(was at stop light)Spark Advance was at 3, IAT at 124 degrees, MAF at 0.794 lb./min, TP at 16.5% I am finding a pattern that is occurring with these MILs-they occur when I am at a stop sign or stop light at idle, low load on engine-when I'm driving at freeway speeds, no problems, no MIL, nothing-I'm looking at whether or not the fuel pressure regulator is the culprit or if the whole fuel pump with the regulator needs to be condemned. At this point I'm at a loss-any ideas at this point?

@GoTechTraining 12 лет назад

We have firing orders with wonderful diagrams available for free on our website. Just click on the link at the beginning of the description on this video. The front of the engine will be where cylinder number 1 is located. Cylinder number 4 is closest to the fire wall. Mark Hicks Wells Vehicle Electronics

@georgeaguilar1264 10 лет назад

I have an 04 Trailblazer with a similar. PO 171 And PO 172 Trouble code and a high idle during normal operating temperatures.

@GoTechTraining 10 лет назад

It is fairly common for a PCM update to cause this on your vehicle. 1. Check the calibration numbers programmed into the Powertrain Control Module (PCM) and compare to the current listing on gm.service.com to check if the PCM has been updated. Click on TIS and then enter the VIN. 2. Install the latest calibration. Mark Hicks Wells Vehicle Electronics

@georgeaguilar1264 9 лет назад

I did the pcm update and replaced the fuel pressure regulator

@GoTechTraining 9 лет назад

George Barnes Hey George, Thanks for the update. Mark Hicks Wells Vehicle Electronics

@GoTechTraining 11 лет назад

It is unusual for just a P0171. Usually a P0174 is along with it. Meaning the entire engine is running lean. Do you have a scan tool you can use? It would help to get the long term fuel trims. Do you have a misfire with the code? The only other suggestions I have without more information is to check the fuel pressure. 60-66 key on engine off and 52-54 running. 59 lbs of pressure with the key "on" is not good enough, if you know what I mean. Stay in touch, Mark Hicks Wells Vehicle Electronics

@DiyMech 12 лет назад

My theory is the modern dealerships don't have the correct calibre of staff, many technicians don't really understand the mechatronics, the use of diagnostics, diagnostic equipment, test equipment in order to trace faults properly. The complexity of the modern vehicle has overtaken their capability they have become reliant on "what the computer tells them",don't get me wrong there are many superb technicians, but there ain't enough of the good ones, & they don't want to work for a dealership.

@GoTechTraining 12 лет назад

@dmorley100 Hey would I pull your leg? ... Well maybe if i thought I could get away with it :). Mark Hicks