DTC P0125

Used my ODB II code reader to troubleshoot a Service Engine Soon light.

It quickly returned the following.

P0125 Insufficient coolant temperature for closed loop fuel control

What does it mean?

Reply to
Ed
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The CTS- coolant temperature sensor is indicating to the ECM-Electronic control module that the engine has not reached proper operating temperature or the threshold point where the ECM switches from open loop to closed loop operation. In open loop the ECM controls various engine functions such as fuel mixture and engine timing using pre-programmed parameters that are stored in the PROM- programmable read only memory. After the engine reaches proper operating temp and all the sensors are operating correctly then the ECM switches to closed loop operation and begins receiving data inputs from various engine control sensors such as TPS-throttle position sensor, MAP-manifold absolute pressure, MAF-mass air flow, CTS.....,AIT-air intake temp., etc etc etc In a nutshell either the engine is running too cool or the CTS is faulting causing the ECM to operate in closed loop or (limp home mode) on the early C3-computer command control systems where i began learning EFI and computer controlled engines. You've got to change your way of thinking when dealing with these systems, sometimes i grab a beer and watch the Disney movie "Tron" when they start testing my patience.

Reply to
Mad Dog

Thanks,

I forgot to mention that the 4x4 is a 1997 Silverado with a 5.7l F1 V8 engine with 125K miles on the odometer.

It quickly returned the following.

P0125 Insufficient coolant temperature for closed loop fuel control

What does it mean?

Reply to
Ed

According to your temp gauge, is it running as hot as it usually does or does it seem to be running cooler?

Doc

Reply to
"Doc"

The engine is not meeting a minimum operating temperature, Replace your thermostat also use the 195* stat.

Reply to
WBucha

His stat might be fine, could be a variety of other things either causing the engine to run cold or causing the PCM to "think" it's running cold. I'd do some more simple diagnostics before I started throwing parts at it.

Doc

Reply to
"Doc"

Doc wrote- According to your temp gauge, is it running as hot as it usually does or does it seem to be running cooler?

Can't tell, since the truck belongs to my Navy son who was transferred to Italy last October, I haven't driven it much until recently. My son told me to sell the truck since he will be in Naples for the next 3 years. I noticed the service engine light on when I drove it for about four miles just to keep it in "shape". I'm not sure how long it has been on. I do know that my son did not tell me anything about it when he dropped it off at my home.

Ed M.

Reply to
Ed

To all-

I checked the coolant level and it was low. It took about a gallon of anti-freeze to top it off. I erased the service engine soon light and drove it for about 6 miles and it remained off.

Thanks for your help.

Reply to
Ed

You have bigger problems...............intake manifold gaskets are likely leaking which is why the coolant was low. You need to check the oil for coolant and find that leak ASAP.

Doc

Reply to
"Doc"

Doc,

Is it a common problem with the Vortec 5700 V8 SFI engine?

Reply to
Ed

Yes, that is why I specifically mentioned the intake manifold gaskets. Check the water pump and all hoses as well, but my dime is on the intake gaskets......

Doc

Reply to
"Doc"

Doc,

Found this url using a GOOGLE search

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No mention of Vortec 5700 V8 engine

WHAT!?! You have a GM 3.4L LOWER INTAKE LEAK too!

So, your low coolant light came on for the second time in a week! You look around and no external coolant leaks. You decide to check the oil. Oil cap & PCV are coated with white sludgy crap. Guess where the the COOLANT went ... into the CRANKCASE via the lower intake manifold gasket!!!

In response to the overwhelming evidence I found while researching my own vehicle, I have created this site to inform others of this Coolant-Oil leak problem with the lower GM intake manifold gasket on late 3.4L V6 GM 199x -

200x Pontiac Montana, Chevy Venture, GrandAm, Alero, etc.

Visit this victims website and read the horror stories that have occurred when coolant mixes with your crankcase oil: Shawn's GM-V6 Lemons

Reply to
Ed

Here is another one. No mention of trucks however.

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From: Teri (Original Message)

I just thought I would let everyone know that I have posted the following on several AOL car care and repair message boards today. I have included the petition link and am hoping more people will go and sign it. This may help us all out. The peition needs to be submitted.

I have a 2000 Monte Carlo SS V6 3.8 with 52,000 miles on it. Car has been very well taken care of. Always had oil changes when due, etc. Just had to have upper & lower intake manifold gaskets replaced for a total cost of $1,225.00. I am out of warranty and GM would offer no cost assistance. I have spent hours searching different sites trying to gather as much info as I can regarding other owners having the same problems. I am just amazed at what I have found. It is very obvious from my research that GM is well aware of the design flaw with their gaskets as they have manufactured an "upgraded" part. If anyone out there is having the same problem, you may be interested in visiting this site

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and signing the onlinepetition. There are over 2,300 signatures so far and growing at an amazingrate. Hopefully there will be a recall someday and we can get our hardearned money back!

Also, I am located in the Chicago area. Yesterday, I contacted several local investigative news stations asking them if they would be interested in doing an investigation and a story regarding this problem. I have also filed complaints with the National Highway Traffic Safety Administration, the Better Business Bureau and the Center for Auto Safety.

I have also written to Mr. G. Richard Wagoner, Jr. who is the President and CEO of General Motors today and I am sending this letter certified. If any one is interested in seeing a copy of this letter, email me and let me know. I also emailed the letter to several different people at GM.

As soon as I hear anything that could maybe help us all I will let you know.

Hopefully, something will come out of all of this.

*******************************
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To: General Motors Corporation & The Better Business Bureau We, the undersigned petitioners, General Motors' customers and/ortechnicians who service GM products, do hereby give notice that we are morethan dissatisfied with the quality of the intake manifold gasket installedin GM vehicles. As of April 10, 2002, there is a nationwide backorder of theintake manifold gasket. At this time, is it not even known when the partwill become available. Being aware of this proves there is a serious problemto be addressed. Because of apparent poor engineering, GM can notmanufacture replacements fast enough for all the vehicles in which they areneeded.

Intake manifold leaks can lead to any number of very serious, and expensive, problems. While the part itself isn't costly, the labor to repair it is very intensive, and has been quoted around $800 USD (give or take a couple hundred depending on the vehicle). This is in addition to any other costly problem(s) the intake manifold gasket leak may have produced.

We are demanding accountability from General Motors. A nationwide backorder should be reason enough for GM to assemble a recall. We can only hope that "the world's largest vehicle manufacturer" who "has been the world's automotive sales leader since 1931" will stand up and claim responsibility for a problem that is so prevalent among their vehicles. Recalls should be mandated in all cases of incompetence, not solely when it affects public safety.

While some of us have been "fortunate" enough to have this problem occur within our warranty, there are many others of us that have had to pay for these expensive repairs just after the warranty expires. Because GM has refused to admit liability on this issue, we feel that this will be a repetitive problem. Once this gasket has been replaced, and customers' pockets drained, GM Service Centers everywhere can expect to see consumers returning, for this same problem that hasn't been rectified due to a designing flaw on GM's part. This error should have been corrected, not the first time in for service, but before entering mass production in millions of vehicles.

Can one presume this is one way of keeping General Motors' patrons coming back time after time?

Sincerely,

The Undersigned

*************

Reply to
Ed

Doc, Finally found some,

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mdstine (Original Message) I own a 1997 Silverado with the 5.7 litre (350 ci) V8 engine. During a service check for hard starting the dealer discovered that it was leaking coolant from the intake manifold gasket. While I have owned it for nearly 5 years it only has 41,500 miles on it. And, as was pointed out in the letter re: the possible class action suit this is not a part that suffers from wear. I have written a complaint to chevrolet and also recieved a half-off deal along with some rhetoric about extended contracts. I am assuming from the conversation I had with the service rep and this reply that this is common in these engines as well. I will attempt to send my information to the lawyer involved in the clase action inquiry.

A co-worker of mine has a 1997 Yukon with the same engine. He has had his IM gasket replaced twice. He has about 100,000 miles on it. I will ask him to add his name to the list as well.

Mark Stine

*********************** From: Justin Sent: 1/25/2003 12:45 PM Hey Mark,

I just found out that I, too, get to replace my intake gaskets on my

1998 Tahoe. Oddly enough, not 5,000 miles ago, I replaced the water pump, had the coolant system flushed, and pressure tested, and refilled. I spoke with a good friend of mine who also owns a 1998 Tahoe, and sure enough (or oddly enough) he replaced his intake gaskets as well. My mileage is 74,000. His mileage was 75,000. Cooincidince? This is like clockwork. We both had our normal service, oil changes every 3,000, etc.

I've written a letter to the dealership, Classic Chevrolet, here in Dallas, TX, to ask that they comp the labor. I've read that some dealerships in Canada are doing this. After all, it's a $14.99 part retail, GM KNOWS there is a problem, and apparently, after the research I've done, it is almost a ceretainty that new intake gasket replacement is in the future of most GM engines with the post 1996 Vortec V-6 or V-8 with the similar cheap gaskets.

I'm pretty livid now, after the research I've done, to have been told that this is normal wear and tear. Bull _____. I researched service bulletins and recalls and issues with Ford and Dodge, and their intake gaskets RARELY fail.

Fortunately for me and my friend, the coolant leaked to the outside, not to the inside, according to the dealership. I'm not so sure I believe them, as there is some engine noise now. Ok, I've done enough rambling, and for sure, enough driving of GM products.

Justin

*****************************************************

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From: alumeye (Original Message) Sent: 1/23/2003 12:29 AM I'm writing a letter to GM right now re: my '98 Olds Silouhettethat has misc. problems including a leaky intake manifold gasket. Was veryexcited to see your petition; great work! As others, I'm curious to knowwhen/ if this petition is going to be sent off to GM? How many signaturesdo you need? I just added the 1519th. Earlier tonight I found this Technical Service Bulletin on this site:

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02-06-01-014 APR 02 Intake Manifold (Lower) - Revised Installation

...which sounds like it might be related to the problem many of us are having with our GM engines. Does anyone know how TSBs work? Are GM dealers required to do these repairs free of charge or at some discount? Does anyone have access to the full details on this TSB? Looks like Alldata.com is in the busines of selling the details.

Tim

************************ And finally:

From: Alyson ~Petition Manager (Original Message) Sent:

6/23/2002 5:27 PM A gentleman who came across our petition has gone yet even further than the petition. Mr. Hawkins had this common problem in his '98 Transport and decided to email a lemon lawyer. With the help of everyone involved, this could lead to a class action lawsuit against General Motors. Following you will find the text of his correspondence with the Lemon Law Lawyers.

--------------------------------------------------------------------

Start of Mr. Hawkins' email

--------------------------------------------------------------------

Dear Sir: I have a 98 Pontiac Trans Sport that had an intake manifold leak at 50,000 miles that caused coolant to leak into the oil. The cost of the repair was about $650. My net research revealed this to be a very common problem. For example see:

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I think this would be an ideal case for a class action suit. I threatened GM with a law suit and they offered to reimburse me 1/2 the repair cost. I refused because they steadfastly refuse to acknowledge that a problem exists with the intake manifold gaskets on this line of V6 engines although the problem is well documented.

This is an excerpt from an email from a person in a similar situation:

"I am having the same trouble with my 99 venture. I am also just beginning my fight with GM. I am also building a website in regards to these motors. I am sure you are aware that this problem is not just affecting the vans, but also most cars with the 3.1, 3.4, and the 3.8 V6 engines. I understand from a friend who is the service manager at a Chevy dealer, that they get them in all the time. He says that GM is in the "denial" stage. They know that the plastic gasket is inferior, but, at least for now, are refusing to deal with the problem. He told me that GM went to the lowest bidder and they screwed up the plastic mixture on the gaskets, and they simply are not lasting, and the company that GM screwed that made the first gaskets is now laughing in their face. He said there are bound to be class action suits popping up everywhere. Unfortunately, he also said that most people are just not realizing that the gasket should very rarely EVER go bad. He told me prior to these engines, they never replace a intake gasket unless they did head gaskets."

(end of excerpt)

What do you think?

Mr. Hawkins [full name & contact information withheld by me, Alyson]

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So it looks like you are right Doc.

I will have to have my friend John look at it.

Thanks again for your comments.

Ed

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Reply to
Ed

How about doing a google search of this ng instead. It's a known, common problem, there is a TSB out to address this issue, and GM has come out with redesigned gaskets to fix the problem.

Doc

Reply to
"Doc"

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