A collection of codes: p0171,po174,po300,po101

[doughboytryme]

hi everyone looking for help have brought my envoy to a local gm dealer for help i have codes of po101,po174,po171,po300 i had replaced mass air flow sensor and gm dealer said it was defective so they replaced it second time still throwing codes went back to see them they scaned it and told me o2 sensors pre cat were failling replaced them still same codes they also told me that it wasnt intake leak or could not see vaccume leak did plugs in august of 2013 i have 174.000 km on my suv i love it but now catalitic converter is starting to smell telling me its failling getting discouraged and also replaced starter other day cause it failed and still have codes really need help please

 

[The_Roadie]

Welcome!

If you're throwing money at a dealer who has the vehicle in their shop with all the GM-required tools in the world, and they can't give you an accurate and competent diagnosis, it's gonna be hard for us to do much more than guess, and give you a list of possibilities.

Are they guaranteeing NOTHING for their diagnostic charge? Are they learning at YOUR expense? I don't get it.

Looking at the O2 sensor real-time data is the way to diagnose the sensors and the cat. Plus an exhaust backpressure test. The dealer has a Tech II high-end scan tool. Did they use that competently to diagnose the sensor issue?

A compression test may be in order for a P0300 misfire code, as long as you have confidence in the injectors.

Any other maintenance history? Routine maintenance all done on time? Anything else done along the way? Have you owned it the whole time?

Do you have access to any competent and trustworthy independent mechanics, or are you married to this dealer who sounds like they've lost your confidence?

 

[doughboytryme]

no roadie not married just thought taking it to gm would be best it is there forte was my thinking but seams i am wrong and yes lost confidence and loosing patience they offered me 1/2 hour of free diagnostics when i or if i go back but the time when they told me 02 sensor they took 2 hours of diagnostics so discouraged i do love my envoy

 

[Hypnotoad]

Welcome to the forum!

I hate seeing a mechanic just throwing parts at cars, especially stealerships. Those hacks owe you much more than a half hour of their time. Time to find a new mechanic.

 

[doughboytryme]

but if a gm dealership can't help who can i trust very discouraged

 

[doughboytryme]

owned vehicle for the last four years oil changes done on regular basis usually before light comes on i do not have faith in injectors just going buy milage that it is so low that couldnt dream injector had failed i had always seen them go on high milages that is also why took it to dealer hoping they are to know this vehicle better than i so thought they know what they are doing and have seen it hundreds of times or know of bulletins that could fix my issue but to no prevail

 

[The_Roadie]

Call the GM regional corporate customer service number. It may be in your Owner's Manual or you can find it in 15 seconds using Google. The dealer should not be able to charge you for a diagnosis and then fail to deliver what you paid for - an accurate, competent diagnosis!

GM Regional HQ should be able to put effective pressure on the dealer.

You had the right thought, and you're the victim here. Members here know many, many tings about the platform that the mechanics can't always remember, but a dealer has access to special tools and support resources we will never have. If they failed to escalate the problem to a higher level of talent within their Region, what are they recommending? An open-wallet, open-ended process that continues to cost you time, confidence, and money?

 

[doughboytryme]

i wanna thank you for your ideas and explaing this is why i joined this site along with another that i wont mention on here to see if i could get ideas help and directions on what to do my truck idles irratic and is causing me greif and gonna cost me a fortune as i said before i do love my truck and would be a shame to get rid of it but so far spent 1000$ on parts and diagnosing at my gm dealership before coming and asking for help on these sites

 

[doughboytryme]

called gm spoke with ambasador well they are to call where i have taken my truck to see what steps they took and pretty much was told its gonna cost me outta pocket till the tap runs dry or they fix it what i was told is they take mesures to correct the problem by replacing the common parts first well i could have done that on my own figured the manufacturer would know and figure it out with out all the parts changing grrrrrrrrrrr lose lose situation cost to repair or lose on trade in for a non gm

 

[Kelly@PCMofNC]

Yikes. Roadie is right, they sound like part changers...not really doing any diagnostic work! Any other place you can take it? Guessing at parts at a dealership gets really expensive fast at their labor rates and retail prices!