'01 Buick Le Sabre SES Light On

dsi1 wrote:
> On 2/26/2014 10:52 AM, Steve W. wrote:
>> dsi1 wrote:
>>> On 2/26/2014 6:53 AM, Bob Villa wrote:
>>>> That's all the print-out gives...and then the possibilities of fault.
>>>>
>>> Thanks to the OBD II, you should be able to solve this problem in 20
>>> minutes or so. :-)
>>>
>>> OTOH, are you having any other symptom than the service engine light
>>> being on? If there isn't, I'd reset the light and see if it gets
>>> another error code gets trapped. Sometimes the don't come back.
>>
>> Maybe if you learned about real diagnostics using a good scan tool you
>> would have repaired the problem in less than 30 minutes.
>>
>> Customers initial complaint -
>> Check engine light on and decreased fuel mileage. (probably low heat as
>> well but may have not noticed)
>>
>> Put scan tool plug into the port turn on key and run a scan.
>>
>> Code says -
>> P0128 = Engine not coming up to full operating temp.
>> No other codes (at least none that the code reader they used show)
>>
>> Possible causes (as any P0XXX is a generic OBDII code)
>>
>> Low coolant
>> Bad thermostat
>> Bad ECT
>> Cooling fan relay failure (fans on constantly)
>>
>> From inside the car -
>>
>> Pull the freeze frame data and it shows the engine had been running for
>> 138 minutes, at 2,100 rpm, at 53 mph and engine load of 12% with a
>> coolant temp of 161 degrees when the code was set (there will be more
>> data but that coolant temp vs run time and load are the ones you need to
>> see for this code.) Normal coolant temp under those conditions would be
>> 210-220 degrees. Yep it's running cold. WHY?
>>
>>
>> A bad ECT will set one or more of the following codes -
>>
>> P1114 - ECT Sensor Circuit Intermittent Low Voltage (sensor/wiring
>> shorting to ground)
>>
>> P1115 - ECT Sensor Circuit Intermittent High Voltage (sensor/wiring
>> shorting to 5 volt reference)
>>
>> P1116 - ECT Signal Unstable Or Intermittent (sensor/wiring faulty)
>>
>> P1117 - ECT Signal Out-Of-Range Low (Thermistor failing with increased
>> resistance)
>>
>> P1118 - Engine Coolant Temp Signal Out-Of Range High (Thermistor
>> failing with decreased resistance)
>>
>> P1119 - ECT Signal Out Of Range With TFT Sensor
>>
>> These are all available on a good scan tool and point directly to the
>> problem. Either the wiring or the sensor unless they used a cheap code
>> reader only and not a scan tool capable of OEM specific codes and didn't
>> get ALL the codes.
>>
>> Go into bi directional control and cycle the cooling fans. They cycle
>> on/off OK
>>
>> So it isn't the fans or ECT sensor causing the code.
>>
>> Open hood. Smell for excess gas, pull dipstick to make sure no gas or
>> water in oil. None noted. (Why, because another possible reason for
>> poor mileage and a cool running engine could be a leaking injector
>> causing a rich mix. Usually this would also set a code but it never
>> hurts to check. Water check because a leaking intake or head gasket
>> could be dumping water into the engine causing a low coolant condition.)
>>
>> Nothing found. Check coolant level in overflow - OK,
>> Check actual coolant level in radiator - OK
>>
>> Most likely fault - Bad Thermostat - Failed fully open.
>>
>>
>> Notify customer - outline possibilities for repair.
>>
>> Drain coolant - replace thermostat - refill
>>
>> Coolant flush (if system shows signs of low maintenance and low coolant
>> concentration) - new thermostat and refill.
>>
>>
>
> I can appreciate your structured approach to weeding out the problem. If
> you're a professional mechanic, you should follow a well thought out
> protocol.
>
> OTOH, it it was my car, I'd just reset the light and see if it happens
> again. My guess is that there's nothing wrong with the fuel injectors
> and that the loss in gas mileage is due to cold weather i.e., it's a red
> herring. The reality is that we need more info on this problem.


No the reality is that the tests showed the problem as a bad thermostat
and resetting the light isn't going to change that.

Checking for excess fuel is simply to rule out any other potential
causes. Part of actually diagnosing the problem and repairing it. As I
said an injector problem should show a code but I've seen them leak and
not show anything.


>
> You might think it's fine and dandy to change parts on a car that has no
> issues other than the check engine light being on but I've never
> operated like that. At the very least, I'd like to be able to replicate
> the problem. I leave the throwing of random parts at a car to the
> professionals. (-:


No, A professional would actually repair the car regardless of who it
belongs to.

The only part that needs changing is the thermostat.


--
Steve W.

Bob Villa wrote:
> On Wednesday, February 26, 2014 8:15:34 PM UTC-6, T0m $herman wrote:
>
>> Put a piece of electrical tape over the light.
>
>> T0m $herm@n
>
> If I replace both parts for about $25...I can break even after a few
> tank fulls! 34 vs 26 MPG is a great savings!
>

Replace the thermostat and you should be good. Does the car have a
working temp gauge? If yes, it gets it's signal from the ECT sensor
which means it's OK.


--
Steve W.

On 2/27/2014 6:49 AM, Steve W. wrote:
>
>
> No, A professional would actually repair the car regardless of who it
> belongs to.
>
> The only part that needs changing is the thermostat.
>
>
You must be practically psychic to be able to diagnose this problem with
limited information. Sure, throwing parts at a car is the preferred
method of professional mechanics and a lot of folks on this newsgroup
but I won't do that myself. I have to pay for the parts.

There's a practical reason for resetting the check engine light - to
verify that the problem is not some random glitch. Change the thermostat
and maybe the light wouldn't come on but that don't mean that's what
caused the original problem.

I'm betting that you're one of those mechanics that answers the
question, "Are you sure replacing the part will this fix the problem?"
with a shrug. I give you the last word on this.

On 2014-02-27 1:17 PM, dsi1 wrote:
> On 2/27/2014 6:49 AM, Steve W. wrote:
>>
>>
>> No, A professional would actually repair the car regardless of who it
>> belongs to.
>>
>> The only part that needs changing is the thermostat.
>>
>>
> You must be practically psychic to be able to diagnose this problem with limited information. Sure, throwing parts at a car is the preferred method of professional mechanics and a lot of folks on this newsgroup but I won't do that myself. I have to pay for the parts.
>
> There's a practical reason for resetting the check engine light - to verify that the problem is not some random glitch. Change the thermostat and maybe the light wouldn't come on but that don't mean that's what caused the original problem.
>
> I'm betting that you're one of those mechanics that answers the question, "Are you sure replacing the part will this fix the problem?" with a shrug. I give you the last word on this.

You seem to be particularly stupid when you say this:

"throwing parts at a car is the preferred method of professional
mechanics"

When in fact, Steve W. has consistently advocated testing and
collection of data as his preferred method of diagnosis. Like any
competent mechanic learned a long time ago.

You've further compounded your mistake by pooh-poohing the utility
of using information that is easily available through the OBD-II
connector because, well, that's the problem, there really isn't any
reason to throw out useful information.

You really should consider just stopping making yourself look any
dumber, although at this point I doubt that is possible.

On 2/27/2014 9:51 AM, Mark Olson wrote:
>
> You seem to be particularly stupid when you say this:
>
> "throwing parts at a car is the preferred method of professional
> mechanics"
>
> When in fact, Steve W. has consistently advocated testing and
> collection of data as his preferred method of diagnosis. Like any
> competent mechanic learned a long time ago.
>
> You've further compounded your mistake by pooh-poohing the utility
> of using information that is easily available through the OBD-II
> connector because, well, that's the problem, there really isn't any
> reason to throw out useful information.
>
> You really should consider just stopping making yourself look any
> dumber, although at this point I doubt that is possible.
>

The only data collected that I saw was an error code PO128. All the
other diagnostic was a fantasy of how he'd proceed if he had the car. If
you read my post, you'll see that I recommended the OP get a cheap
OBDII. Did you even bother to read my post? Feel free to spend your
money on expensive diagnostic equipment. It's a great idea if you got
the money to burn.

The code readers are great for reading the error codes - that's all. My
mechanic won't fix an intermittent problem unless he can reliably
replicate it. I'm in the repair business and I won't do **** like that
either. That's all I gots to say about that. :-)

dsi1 wrote:
> The only data collected that I saw was an error code PO128. All the
> other diagnostic was a fantasy of how he'd proceed if he had the car.
> If you read my post, you'll see that I recommended the OP get a
> cheap OBDII. Did you even bother to read my post? Feel free to spend
> your money on expensive diagnostic equipment. It's a great idea if
> you got the money to burn.
>
> The code readers are great for reading the error codes - that's all.
> My mechanic won't fix an intermittent problem unless he can reliably
> replicate it. I'm in the repair business and I won't do **** like
> that either. That's all I gots to say about that. :-)
>

Then you need to learn how to read.

Here is the Original post

> Bob Villa wrote: OBD2 (from AZ) 1.)Low Coolant, 2.)Thermostat
> defective, 3.)ECT defective Coolant is up to proper level-could there
> be an air gap at the ECT? Temp gauge and heat are working. If there
> is no air gap at the ECT, that would seem to be bad. 85K,2nd
> owner-with moderate knowledge.
>
> Anything to add would be appreciated!

So in this post Bob says AZ told him these were the problems that could
cause the code (but he didn't list the code)


Next post: As a reply to Tegger

On Wednesday, February 26, 2014 9:18:04 AM UTC-6, Tegger wrote:
>> Please give the actual alphanumeric codes, not the text
>> descriptions. Codes are a letter followed by four numbers
>> (sometimes also letters as well). Example: P0301.

> P0128

So now we have an actual code. And the first post does show correctly
the most likely problems to cause this code.


Your first response :

On Wednesday, February 26, 2014 11:18:34 AM UTC-6, dsi1 wrote:
>> On 2/26/2014 6:53 AM, Bob Villa wrote:
>>>> That's all the print-out gives...and then the possibilities of
>>>> fault.
>>
>> Thanks to the OBD II, you should be able to solve this problem in
>> 20 minutes or so. :-)

>> OTOH, are you having any other symptom than the service engine
>> light being on? If there isn't, I'd reset the light and see if it gets
>> another error code gets trapped. Sometimes the don't come back.

And Bobs Reply :
> After taking a trip the MPG is 20% or so worse...and I would need the
> scanner to reset the fault.
> I think I will change the stat ($8.50) and then the sensor ($18.50) if
> needed.


So now we have a Code pointing at a possible problem.
A symptom (poor gas mileage occurring while the light is on)
And the probable repairs needed.


My response laid out how it is possible to use a REAL scan tool (not a
cheap POS code reader) to diagnose the fault, and do it while the
vehicle is there the first time. I also included checking a couple of
other items that may cause a similar problem. IE a leaking injector
could cause lowered mileage, or a fan relay stuck on which would keep
the coolant at a lower temperature. Both of those are dead simple to
check and might take 20 seconds.

I also said that if AZ couldn't pull OEM specific codes (which most of
the low end tools won't). That it could still be a bad ECT, BUT since he
stated that the temp gauge still worked, The likelihood of it being the
ECT is much less. And what codes it would throw if bad.


So you want to tell me exactly how it is "throwing random parts at it"
when I listed the two parts that could be the problem. And narrowed that
further to ONE part?


Based on your posts you seem to think that a REAL scan tool is useless.
Fine stay in the dark and don't bother using a tool which can make it
1000 times easier to accurately diagnose a problem, and give the
customer the repair options on the first visit.

Fine.

When your customer comes here and tells me "I went to this guy who
didn't even test the car just turned out the light and said to drive it,
bring it back if the light come back on"

I'll be more than happy to have them as a customer.

--
Steve W.

On Thu, 27 Feb 2014 10:42:36 -1000, dsi1
> wrote:

> Feel free to spend your
>money on expensive diagnostic equipment. It's a great idea if you got
>the money to burn.

Another great idea if you've got money to burn is to not properly
diagnose the car. In other words, guessing, which appears to be what
you're advocating.

>The code readers are great for reading the error codes - that's all.

That's why they're called code readers.

>My mechanic won't fix an intermittent problem unless he can reliably
>replicate it. I'm in the repair business and I won't do **** like that
>either. That's all I gots to say about that. :-)

That's a really swell philosophy, but there are people who want their
cars fixed, and are willing to pay a competent mechanic to guess. I
was always honest with customers, and told them what the most likely
cause was, but warned them that there could be multiple problems. At
that point, they get to make the decision, and they know what they're
in for. There's lots of people out there with lots of money, and they
are willing to take a chance.

On Thu, 27 Feb 2014 09:17:58 -1000, dsi1
> wrote:

> Sure, throwing parts at a car is the preferred
>method of professional mechanics

Sorry, but that's ridiculous, unless you're talking about dishonest
"professionals". The only other situation is in new car dealers, which
is where I spent all my working life. There are times when you must
guess, but it's the factory that pays, not the customer. In fact, it's
the factory that tells you to guess, or that guesses for you.
Unfortunately, some of the mystery problems never get sorted out, and
remain impossible to diagnose. That's life.

>There's a practical reason for resetting the check engine light - to
>verify that the problem is not some random glitch. Change the thermostat
>and maybe the light wouldn't come on but that don't mean that's what
>caused the original problem.
>
>I'm betting that you're one of those mechanics that answers the
>question, "Are you sure replacing the part will this fix the problem?"
>with a shrug.

What's wrong with being upfront with the customer? "I don't know" is a
refreshingly honest answer to a lot of them. And if their car is
stalling about once every three months on the expressway at 70 mph,
they will probably be very willing to pay for a guess.

You have clearly never worked as a mechanic, so you need to understand
that some people here have.

Bill Vanek wrote:
> On Thu, 27 Feb 2014 09:17:58 -1000, dsi1
> > wrote:
>
>> Sure, throwing parts at a car is the preferred
>> method of professional mechanics
>
> Sorry, but that's ridiculous, unless you're talking about dishonest
> "professionals". The only other situation is in new car dealers, which
> is where I spent all my working life. There are times when you must
> guess, but it's the factory that pays, not the customer. In fact, it's
> the factory that tells you to guess, or that guesses for you.
> Unfortunately, some of the mystery problems never get sorted out, and
> remain impossible to diagnose. That's life.
>
>> There's a practical reason for resetting the check engine light - to
>> verify that the problem is not some random glitch. Change the thermostat
>> and maybe the light wouldn't come on but that don't mean that's what
>> caused the original problem.
>>
>> I'm betting that you're one of those mechanics that answers the
>> question, "Are you sure replacing the part will this fix the problem?"
>> with a shrug.
>
> What's wrong with being upfront with the customer? "I don't know" is a
> refreshingly honest answer to a lot of them. And if their car is
> stalling about once every three months on the expressway at 70 mph,
> they will probably be very willing to pay for a guess.
>
> You have clearly never worked as a mechanic, so you need to understand
> that some people here have.


Sounds like a GM Crank Sensor....


How about a Dodge Ram 2500 w360. Drive down the road and it's fine one
second. Bucking hard enough to break your neck the next. Toss the
scanner on and drive down the road. HMM that ain't right. That ECM isn't
supposed to shut down on it's own.

Solution, new O2 sensors.
They were heating up and shorting the signal line and the 12 volt heater
feed. Was enough to shut the ECM down. Engine would buck, power drop
would reset the ECM and rinse lather repeat....


--
Steve W.

On Thu, 27 Feb 2014 23:08:44 -0500, "Steve W." >
wrote:

>Bill Vanek wrote:
>> On Thu, 27 Feb 2014 09:17:58 -1000, dsi1
>> > wrote:
>>
>>> Sure, throwing parts at a car is the preferred
>>> method of professional mechanics
>>
>> Sorry, but that's ridiculous, unless you're talking about dishonest
>> "professionals". The only other situation is in new car dealers, which
>> is where I spent all my working life. There are times when you must
>> guess, but it's the factory that pays, not the customer. In fact, it's
>> the factory that tells you to guess, or that guesses for you.
>> Unfortunately, some of the mystery problems never get sorted out, and
>> remain impossible to diagnose. That's life.
>>
>>> There's a practical reason for resetting the check engine light - to
>>> verify that the problem is not some random glitch. Change the thermostat
>>> and maybe the light wouldn't come on but that don't mean that's what
>>> caused the original problem.
>>>
>>> I'm betting that you're one of those mechanics that answers the
>>> question, "Are you sure replacing the part will this fix the problem?"
>>> with a shrug.
>>
>> What's wrong with being upfront with the customer? "I don't know" is a
>> refreshingly honest answer to a lot of them. And if their car is
>> stalling about once every three months on the expressway at 70 mph,
>> they will probably be very willing to pay for a guess.
>>
>> You have clearly never worked as a mechanic, so you need to understand
>> that some people here have.
>
>
>Sounds like a GM Crank Sensor....
>
>
>How about a Dodge Ram 2500 w360. Drive down the road and it's fine one
>second. Bucking hard enough to break your neck the next. Toss the
>scanner on and drive down the road. HMM that ain't right. That ECM isn't
>supposed to shut down on it's own.
>
>Solution, new O2 sensors.
>They were heating up and shorting the signal line and the 12 volt heater
>feed. Was enough to shut the ECM down. Engine would buck, power drop
>would reset the ECM and rinse lather repeat....

The description I used as an example was an earlier CTS. It would do
exactly what I said, with the factory helpfully adding, "with no
driver input". In other words, it was impossible to duplicate. They
found a workaround, but I don't think they ever found a fix. Some
owners of those cars were pretty, uh, shaken when that happened. At
least they would start back up immediately, but the average driver
does not have the presence of mind to slip the car into neutral, and
quickly restart it, without losing too much speed. It seemed there was
always a semi on their back bumper when it happened...

And now that I think of it, it was a bad example to use in this
thread. You could throw every imaginable part at this problem, and
none of them would have fixed it.