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2003 gmc envoy_sle_xl
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Discussion Starter · #1 ·
I have searched countless amounts of threads and know mostly what I have to do, but just want to make a thread and see what you guys think. This is the story...

My dad has an 2003 Envoy XL V6 with 190,000 miles and the check engine light has been on. The car would have very high rough idle and it felt like the car had no low gears because it would have no acceleration and would sound like a semi coming down the road. Gas Mileage has gone down to 13mpg. We have taken it to the dealer 4 times and other mechanics and they have no idea what is wrong. So we took it to our Uncle who works in Chrysler and used his diagnostic tool and came up with the following errors;

P0105
P0128
P0495
P0753

So from this I get we have to change Map Sensor, Coolant Thermostat, Fan Clutch, and the Shift Solenoid, but the last one might be the ignition coil. This continued for 2 years.

Then about 3 months ago the car suddenly died. We tried to jumpstart it but it failed so we took it to the mechanic and they replaced the battery, alternator, and one coil pack for the car. Then after starting the car the alternator failed and they changed another one. This semi fixed it because the car died every time the A/C was on but after disconnecting the wire for A/C the car runs everyday but there is still fluctuations in the voltage during IDLE.

Basically we are fed up with retarded people trying to fix this car and screwing things up. I have no trust in anyone besides this forum and myself in trying to help my dad. Please let me know if the solutions for the codes are correct and what I should do about the latter problem. Hopefully you guys can help me out. Thanks
 

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2005 chevy trailblazer_ls_ext
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I have searched countless amounts of threads and know mostly what I have to do, but just want to make a thread and see what you guys think. This is the story...

My dad has an 2003 Envoy XL V6 with 190,000 miles and the check engine light has been on. The car would have very high rough idle and it felt like the car had no low gears because it would have no acceleration and would sound like a semi coming down the road. Gas Mileage has gone down to 13mpg. We have taken it to the dealer 4 times and other mechanics and they have no idea what is wrong. So we took it to our Uncle who works in Chrysler and used his diagnostic tool and came up with the following errors;

P0105
P0128
P0495
P0753

So from this I get we have to change Map Sensor, Coolant Thermostat, Fan Clutch, and the Shift Solenoid, but the last one might be the ignition coil. This continued for 2 years.

Then about 3 months ago the car suddenly died. We tried to jumpstart it but it failed so we took it to the mechanic and they replaced the battery, alternator, and one coil pack for the car. Then after starting the car the alternator failed and they changed another one. This semi fixed it because the car died every time the A/C was on but after disconnecting the wire for A/C the car runs everyday but there is still fluctuations in the voltage during IDLE.

Basically we are fed up with retarded people trying to fix this car and screwing things up. I have no trust in anyone besides this forum and myself in trying to help my dad. Please let me know if the solutions for the codes are correct and what I should do about the latter problem. Hopefully you guys can help me out. Thanks
Rough idle or dying after having the battery disconnected AND the A/C on is a sure sign of a dirty throttle body. We've seen this NUMEROUS times here.
We have a how to article here on how to clean it. It's pretty easy.

Pulling the plug on the a/c is treating the symptoms, not the cure.

As for voltage fluctuations at idle, it could be the battery terminals are a little loose or dirty, or if it is only doing at startup could be the air pump.
 

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2003 gmc envoy_sle_xl
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Discussion Starter · #4 ·
I have seen most of the threads that cover these issues. But my main concern is will they help fix the problems? I don't want my dad to waste money on parts because he will get fed up with me naming random stuff because I said I could do that same thing the mechanic is doing but get parts at cost and do labor for free. That is why he is doing it.

I had a fully built and boosted accord and he saw how I took the car he bought brand new and turned it into something crazy after he gave it to me as my first car. I spent countless amount of money fixing problems and he is just reminded of those days and doesn't want the same thing to happen to the Envoy because I am working on it. My dad can get a lil stubborn :Excuse my rant:
 

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2004 gmc
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My dad can get a lil stubborn
Allowing a Check Engine light issue to go on for 2 years is beyond stubborn. It's a good way to turn a vehicle problem into a problem vehicle.

We don't have a tech tool like the dealer to plug into your father's Envoy. We don't have the background (yet) to know how the vehicle is treated, pampered or abused. Advice you get on an Internet forum is worth about as much as you're paying for it.

Now that you understand we can't be totally entrusted with your father's vehicle or repair your relationship with him, let's get on with the project.

Start with the easy one - filthy throttle body.

The thermostat may or may not be next, depending on what temperature your gauge is sitting at. Is it normally at 210, or less? How much less? Low coolant temp could definitely result in driveability problems. Amazing the OEM thermostat lasted this long. Assume you haven't already changed it out once?
 

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Discussion Starter · #6 ·

ALSO another problem I forgot to mention is that Cruise Control stopped working about 2 yrs ago too.


the roadie said:
The thermostat may or may not be next, depending on what temperature your gauge is sitting at. Is it normally at 210, or less? How much less? Low coolant temp could definitely result in driveability problems. Amazing the OEM thermostat lasted this long. Assume you haven't already changed it out once?

The temp is pretty normal meaning that it stays around 210. I can check that tomorrow as well. I don't think anything has been changed on the car besides what I have said.

I understand where you're coming from. Well he finally paid the price by letting this car go without any repair.

I have already replaced the map sensor and checked all the fuses. I can't seem to find the fuse for the ECU so I can reset it, so any help with that will be appreciated also.

Thanks so far for the great responses. Hopefully I can get this car running back to OEM standards :rolleyes:
 

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Western Canada Chapter
2003
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6,411 Posts
You can disconnect the neg battery cable to reset any codes.

From what I have read, the P0105 code and the MAP sensor issue seem to be related to a malfunctioning cruise control. :undecided

Seems like you have all info you need to start getting that thing up to par :thumbsup:
 

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The dead cruise control is a side effect, not a cause. Many other things that set error codes will also disable the cruise control as a safety feature. It also serves to annoy the driver more, in hopes that they will get with the program and fix the problem's root cause.

Start with disconnecting the battery cable, then cleaning both sides of the TB using the how-to article. Nothing else you do will give a valid result until you have a properly-working TB.

With the temp gauge reading 210, sounds like the thermostat isn't a root cause, and the error code that mentions it could be bogus, or caused by something else.

Oh, can you confirm that your Dad changes the fluids at the recommended intervals? If he believes in 50,000 mile oil changes we might as well stop here because the vehicle is beyond hope.
 

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:iagree: with rodie, super88, and the rest of the gang. clean the throttle body and see what it does. It will definitely need it if it hasn't been done before in the past 190k miles. As mentioned before, disconnect the battery during the process. Since the throttle bodies are drive-by-wire (electronic) the littlest amount of dirt can have a great effect. These things are VERY sensitive.

and by the P0495 code, your fan clutch may be faulty, explaining why you get the 13 mpg. does the engine roar on start up like a f16?
 

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he did say it sounds like a SEMI coming down the road.... and that sure sounds like a fan clutch locked on FULL-- and the side effect is more gas consumed... this along with a thermostat staying open will lower gas mileage.

so this kid has to CLEAN the throttle body 1st- that way he can possibley get the AC working again(and most likely will not kill the engine anymore).
then we can proceed with the possible bad thermostat.

the temp needle should practically SIT at the 210 mark, if its below that by a tick mark or 2. then its probably bad.

once these 2 items are corrected-- we can proceed with the other stuff...

But rhdube16--- sounds like you have mechanical know how..
the throttle body cleaning will cost you maybe $5 for the spray.
and about 1 hour of your time... do this 1st...
very cheap and easy to do--- and can rid you of one of the major problems.
 

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Western Canada Chapter
2003
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The dead cruise control is a side effect, not a cause. Many other things that set error codes will also disable the cruise control as a safety feature. It also serves to annoy the driver more, in hopes that they will get with the program and fix the problem's root cause.
It was late :eek: and now that you said it right, the way I worded it looks even more goofy. :duh:
 

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Discussion Starter · #13 ·
Alright guys I cleaned the throttle body and reset the ECU. The car is noticeably quieter but the acceleration is still VERY laggy which I think could be because of the fan clutch or air pump. What do you guys think?
 

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It can't be the air pump, because that's only active for a few seconds at start-up, and if it fails that diagnostic, it comes on again a few times in the next 5-15 minutes for a few seconds, but it's definitely not running much of the time.

If you have a loud roaring noise all the time, try the fan clutch next. What codes are present now?
 

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Discussion Starter · #15 ·
OK guys here is the update...

Did a diagnostic test and it still showed the Coolant Thermostat and the Shift Solenoid errors. The other 2 are gone but the engine still sounds crazy loud. I still think a fan clutch could be the issue but don't wanna waste money if its not. Could the remaining 2 problems cause this loud noise from the engine, because it sounds like a freaking semi?
 

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You could always remove the blades from the fan clutch and see if the noise stops. But they have such a high history of failure, and a new one is under $200, that if it was me I'd just swap it. To troubleshoot it with absolute certainty would take driving around with a high-end scan tool that can look at the commanded fan RPM versus actual fan RPM parameters, and those (if you don't have a friend with one or the $500 software packages that do the same) will cost more than a new fan clutch.
 

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2002 olds bravada
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...you said that one of the codes that you see are shift solenoid errors. I had these codes on my 1997 Bravada, which uses the (same) 4L60E transmission. One of my shift solenoids died at ~165,000 miles. With yours at 190,000, I wouldn't be surprised if it's bad.

If the solenoid codes are there, it is entirely possible that your transmission is in "limp-home" mode, which means it stays in second gear any time you are in drive. This would explain the very lazy acceleration -starting out in second gear makes it accelerate slowly. It's easy to tell - accelerate from a stop and see if you can feel the transmission shift, or see a shift on the tachometer. Also, if you go 70mph and your tach is above 3000 RPM, it's probably in second gear limp home mode.

On my 1997, I ordered the solenoids from Ebay (pretty cheap, around 20 bucks a piece I think), got a pan gasket and tranny fluid from a local parts store, and spent about two hours under the vehicle. The solenoids are held in with clips, and are very easy to swap out once you remove the pan. You'll just get tranny fluid in your hair while you're down there...

It's possible that the cooling fan being on 100% of the time is something that automatically happens when the vehicle is in limp-home mode.

Anyway, before I dug too deep into anything else, I would check the tranny to see if it's in limp-home mode. If it is, fix it and get those codes cleared before you do anything else.

Good Luck,
Mike

PS: I cleaned my throttle body today, and it cleaned up near-stalling problems with the AC on. Highly recommended for 5 bucks and a half hour.
 

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also had thermostat and solenoid codes

First, thanks for all the info and advice about changing the thermostat; my husband did it Saturday and all's well with that (except that 3rd bolt that was mentioned--it got lost somewhere and we have to buy one). The check engine light did go out--briefly. We took it back to Auto Zone to run the diagnostic check and got this PO753 electrical/solenoid code. The vehicle seems to run fine and has all along. Don't notice the sluggishness that one of the other posters mentioned, nor is it loud. The only thing I can sort of notice that it does sometimes seem to run slightly rough in 1st gear, like you're on a bumpy road. But I wouldn't even say that's consistent. Should we try to replace the solenoid? Are instructions on how to do that somewhere in the website?
THANKS AGAIN!:thx
 

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First, thanks for all the info and advice about changing the thermostat; my husband did it Saturday and all's well with that (except that 3rd bolt that was mentioned--it got lost somewhere and we have to buy one). The check engine light did go out--briefly. We took it back to Auto Zone to run the diagnostic check and got this PO753 electrical/solenoid code. The vehicle seems to run fine and has all along. Don't notice the sluggishness that one of the other posters mentioned, nor is it loud. The only thing I can sort of notice that it does sometimes seem to run slightly rough in 1st gear, like you're on a bumpy road. But I wouldn't even say that's consistent. Should we try to replace the solenoid? Are instructions on how to do that somewhere in the website?
THANKS AGAIN!:thx
P0753- Shift Solenoid A Electrical

now might be a good time to take the truck to a transmission specialist and have them take a look at it.
 

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Honestly, if this were my vehicle, I would take the time to replace the solenoid first. It's really not hard to do. Do a search for "4L60E solenoid replacement" on the internet, and you can probably find a write-up. That's how I learned to do mine. Using the same search, you can also find a schematic that shows which solenoid is which.

Any GM dealer will have the solenoid. It's very common. Should cost less than $30 at a dealer, or around $20 off the internet.

Basic procedure is as follows:
1. Hoist the vehicle.
2. Remove the transmission pan (this is the messy part).
3. Locate the solenoid in the valve body of the transmission. If my memory is correct, it's located at the rear of the valve body.
4. Use a pair of pliers of a screw-driver to remove the retaining clip by pulling straight downward. It should pop right out.
5. Remove the solenoid by pulling it rearward. It will come right out.
6. Remove the electrical connector from the solenoid.
7. Install the new solenoid by doing the reverse of steps 4, 5, and 6.
8. Install the pan and re-fill with transmission fluid.
9. Start the vehicle and test drive.
10. Clear the trouble code.

While you are down there, I would suggest replacing all of the solenoids in the transmission. You can buy kits that contain all of the solenoids for a low price. All of them are pretty easy to remove and re-install.

You can probably replace all of the solenoids in the transmission for about the same cost as you would pay to have a transmission shop diagnose your vehicle. If it were me, I would spend the money and time to replace all of the solenoids first. Based on this code, it's about 90% or more likely that the solenoid itself is bad.

Good Luck,

First, thanks for all the info and advice about changing the thermostat; my husband did it Saturday and all's well with that (except that 3rd bolt that was mentioned--it got lost somewhere and we have to buy one). The check engine light did go out--briefly. We took it back to Auto Zone to run the diagnostic check and got this PO753 electrical/solenoid code. The vehicle seems to run fine and has all along. Don't notice the sluggishness that one of the other posters mentioned, nor is it loud. The only thing I can sort of notice that it does sometimes seem to run slightly rough in 1st gear, like you're on a bumpy road. But I wouldn't even say that's consistent. Should we try to replace the solenoid? Are instructions on how to do that somewhere in the website?
THANKS AGAIN!:thx
 
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