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GM DTC CODE P1639

i HAVE A 2002 V6 3800 FIREBIRD .i GOT A CHECK ENGINE LIGHT. IT . IS A 5 VOLT REFERENCE CIRCUIT 2. I NOW ABOUT THE 5 VOLT, BUT WHAT IS CIRCUIT 2 ? LONG STORY SHORT I TOOK IT TO A GM DEALER HE SAID IT NEEDED A AC PRESSURE SENSOR $263.00 .THENI DROVE THE CAR AND THE LIGHT CAME BACK ON. THEN HE SAID IT NEED A NEW FEUL PUMP PRESSURE SENSOR $900.00 NOW IT NEED A NEW PCM $ 708.00 ..ON TOP OF THAT THE 2 HE ORDERED WERE BAD..HE SAID THEY DONT MAKE MINE ANYMORE.WHEN I CHECKED FOR 5V AT THE AC SENSOR I GOT 4.99,SO I THINK HE GOT ME.HE HAS HAD MY CAR FOR 2 WEEKS IS THERE SOME THINK I CAN CHECK? i CANT FIND AY THING ON THE CODE ALSO WHEN I GOT THE CAR BACK I GOT A MISFIRE CODE. . WHEN I GOT THE P1639 CODE IT SHOWED A R/L RESPONSE TO L/R RESPONSE RATIO INTHE 02 SENSOR B1S1.????HOW DO I FIX THAT? DOES ANY BODY THINK THE DEALER IS SCAMMING ME ? THANKS FOR ANY BODIES HELP.

Quote:

Originally Posted by billmill5050 (Post 1625385)

OMG maybe you are or are not getting scammed, however, you are getting taken for a bunch of parts swapping.

Then I looked for anything called "fuel pressure" anything at Napa and find that the most expensive part there is $63.00 so maybe you are getting scammed.

I believe the pressure switch for the AC is like $20.00. This is the low-pressure sensor I'm thinking of.

They DO still make the PCM, although it will be a refurbished unit. If GM proper doesn't do it then someone else does. Thing is they have to program it once it arrives in their shop. Many dealers don't know this for some strange reason.

A fuel pump is usually under $400.00 , and the pressure regulator under $63.00 . Not sure where $900.00 comes from unless perhaps a lot of labor . . . ? Before doing any of this I'd wonder if anyone hooked a pressure gauge up to see how the current one is working.

Either way, go find a reputable auto repair shop. Dealers often are unable to efficiently diagnose anything that isn't young enough to be on factory warranty. I know I know: there are good dealers out there and reputable ones too, but when the older cars start down this path at a dealership then it is usually best to run away.

billmill5050 Welcome to the forums.
In the future, we would appreciate if you would not post all in Capitals. (turn CAPS lock off)
Forum members can take offense to this, as may be interpreted as "shouting" or "yelling"
Thank You for your understanding.

Cathedral Club, I totally disagree...

Quote:

Dealers often are unable to efficiently diagnose anything that isn't young enough to be on factory warranty. I know I know: there are good dealers out there and reputable ones too, but when the older cars start down this path at a dealership then it is usually best to run away.

If a dealership can't fix it's own cars, they should close down the place.....a freakin' 2002 is old? Do you diagnose a 2002 differently from 2018? Absolutely not.....and a GM dealership has access to every TSB and manual on this vehicle, or have techs forgot how to read?

I don't know if we have all the facts on this case....for one thing, I would like to know what the original code was.....If P1639, what does this have to do with a fuel pressure sensor?

We went from an A/C pressure sensor, to a fuel pressure sensor, to a PCM.....and they had the vehicle two weeks?

I'm sure there is more to the story......all I know is, when we diagnosed a problem, and we told the customer this would fix it, it better fix it....otherwise, we better have a reason for it(there was more than one problem).......some guys either don't take pride in their work, or maybe they don't know what they are doing(yes, there are parts changers in dealerships).....Let's face it most places are flat rate.....and the guys that are the diagnosticians in the shop better know their sh*t, or comebacks will kill them......unfortunately, flat rate only gives you so much diagnostic time, and some guys take short cuts......

Quote:

Originally Posted by Tech II (Post 1625409)

Cathedral Club, I totally disagree...

If a dealership can't fix it's own cars, they should close down the place.....a freakin' 2002 is old? Do you diagnose a 2002 differently from 2018? Absolutely not.....and a GM dealership has access to every TSB and manual on this vehicle, or have techs forgot how to read?

I don't know if we have all the facts on this case....for one thing, I would like to know what the original code was.....If P1639, what does this have to do with a fuel pressure sensor?

We went from an A/C pressure sensor, to a fuel pressure sensor, to a PCM.....and they had the vehicle two weeks?

I'm sure there is more to the story......all I know is, when we diagnosed a problem, and we told the customer this would fix it, it better fix it....otherwise, we better have a reason for it(there was more than one problem).......some guys either don't take pride in their work, or maybe they don't know what they are doing(yes, there are parts changers in dealerships).....Let's face it most places are flat rate.....and the guys that are the diagnosticians in the shop better know their sh*t, or comebacks will kill them......unfortunately, flat rate only gives you so much diagnostic time, and some guys take short cuts......

the check engine light code was a GM code P 1639.and my OBD 2 should the other about the O2 sensors .Im the original owner

Quote:

Originally Posted by Tech II (Post 1625409)

the check engine light code was a GM code P 1639.and my OBD 2 should the other about the O2 sensors .Im the original ownerhttps://www.gmforum.com/images/statu...ser_online.gif https://www.gmforum.com/images/buttons/reputation.gif https://www.gmforum.com/images/buttons/report.gif

last year they put in a feul pump for $1500 $500 for pump & 1000 labor

$1000 is ridiculous for labor........What was the labor rate? How many hours did it take?