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-   -   My check engine light is on (http://cellar.org/showthread.php?t=22430)

Nirvana 04-17-2010 12:45 AM

My PT Cruiser is playing the check engine light game but I do believe I have a short in the cooling system because I get air conditioning on the regular fan if the temperature gauge is all the way on the blue. In the Cruiser its the fan that is supposed to designate air conditioning or just plain air.

Cloud 04-17-2010 08:50 AM

if it were just the light, I'd ignore it, but it's the engine performance. It's running ragged, and the engine is (sometimes) sputtering or hesitating. Gets my heart in my throat, I tell ya. The manual just says that continued driving with the CE light on may damage the emissions system.

sorry, monster & tw if I'm a car idiot. Actually, it's more of a tool/handy person idiot, but I've found after painful experience (and experimenting) in my life that such things are better left to people more adept with manual skills than me. I know my strengths, and that ain't one of them.

tw 04-17-2010 06:54 PM

Quote:

Originally Posted by Cloud (Post 416380)
Yeah, I know they are easy tasks, and I could learn to do them. But dammit, I don't wanna!

Which is why some people also much carry many green 2.75 by 6 inch sheets of paper in their wallet. Go somewhere and ask them to open the radiator. You observe what is inside and then ask the 'assistant' what he sees. The put the cap back on. Do not do anything else (but give him sheets of green paper). Then post here what was observed. Solutions are that simple - step by step.

It is required in most states.. If an errror code exists, then the car fails inspection.

xoxoxoBruce 04-17-2010 08:04 PM

At this point she's committed, to the tune of $800, and they didn't fix the problem. She has to go back to them and make them fix it, or get her money back and go elsewhere.

tw 04-17-2010 10:12 PM

Quote:

Originally Posted by xoxoxoBruce (Post 649735)
She has to go back to them and make them fix it, or get her money back and go elsewhere.

Plenty of options exist. When we choose not to learn basics, then compensate by moving plenty of green paper through wallets. It creates jobs. That's what paper is for. Compensates for not wanting to learn and compensates for labor. And so the term 'just compensation'.

Bottom line: simplest solution if one cannot check fluids in the radiator. Replace the Idle Air Control Valve. Just pay the money. DTC implies it is getting stuck as engine temperature changes. It does not necessarily explain the failure. But then other critical details (not provided) would probably define that or some other problem. Those details will not be forthcoming. So just replace the Idle Air Control Valve.

Only better techs would put an oscilloscope on the IACV wire. Then that problem could be observed. Most techs do not have sufficient knowledge and tools. And would be further stifled by insufficient details. What will they do? Replace the IACV - the shotgun solution.

Bottom line - that $800 spent on a new computer is gone. No way to recover that money - unless the dealer has a special place in his heart for Cloud. Move on. Replace the IAC valve (which was always my #1 suspect (considering almost no facts). A new valve has about a 65% chance of success - clearly the best option at this point. More money is the only remaining solution.

xoxoxoBruce 04-17-2010 10:47 PM

Bullshit, they took her money to fix the problem, and didn't. They owe her $800 dollars worth of fixing.

Cloud 04-18-2010 10:22 AM

I'm sure they'd be willing to refund me the $500 + for the actual part . . . if they removed it and put my old PCM in there (if they even still have it). Don't really want that, though, nor do I want to make a big scene. I received the same diagnosis and suggest for a fix from two different places, and went with that, but I knew there was a chance that it wouldn't fix the problem. I will keep trying--have to, anyway, since it's my only transportation option.

I really appreciate everyone's advice. The Cellar is really great for that! I refuse to be ashamed that I'm not good at fixing cars. I'm not an idiot, but I'm not handy, either. I try to keep my car well-maintained anyway.

In the end, I listen to advice and use my own common sense.

tw 04-18-2010 11:51 AM

Quote:

Originally Posted by Cloud (Post 649821)
I received the same diagnosis and suggest for a fix from two different places, and went with that, but I knew there was a chance that it wouldn't fix the problem.

They simply followed a simplistic diagnostic chart. It says if the valve clicks when voltage is applied, then replace the computer.

Well, an idle air control valve actually opens and closes quickly per commands from the computer. So quickly as to need an oscilloscope to actually see it. Computer monitors how fast the valve is responding. If the response is not what was ordered, then the computer flags a check engine code. If the valve works normally but too slow, then computer gets replaced (if only following the diagnostic chart). Valve can be sticky, partially clogged, etc. and still pass the on-off test.

The entire circuit is real simple. Computer tells valve to open and close rapidly. Valve opens and closes rapidly. If valve does not do that fast enough, then an error code is created. Only three things in that circuit - computer, wire, and valve.

How I would have responded? I would have asked why they knew the computer was defective. I never mention the IACV. Let them mention the valve and why they know the $200 valve is not defective. I have found only some mechanics who really know their stuff because the word why is used heavily. The stuff I do not know then gets confirmed later with an internet search.

If anyone tells me something without the reasons why and without numbers, then he is lying.

Standing in the dealer to get a new oil filter or wiper blades is very educational. Watching them talk to women quickly separates honest dealers from the shady ones. Numbers (verses no numbers) quickly identifies the honest ones.

xoxoxoBruce 04-18-2010 07:30 PM

1 Attachment(s)
Sure, they went through the diagnostic procedure, and when some part that is acting up intermittently, worked at the time, they blamed the PCM.

tw 04-19-2010 05:20 PM

Quote:

Originally Posted by xoxoxoBruce (Post 649873)
Sure, they went through the diagnostic procedure, ...

Diagnostic procedure does not work for intermittent problems. It can only identify a constantly defective part. Intermittents require additional facts.

In a previous discussion, I noted Toyota's biggest problem. People. In this case, the mechanic cannot really be effective if, for example, the exact conditions during every 'failure' are not defined. For example, Cloud later noted that this failure occurred as the car was warming. Also critical are factors such as where the temperature needle on the gauge was located during each failure? Was it accelerating or during constant speed? How many minutes after starting the cold engine? How much gas in the tank? Was air conditioner on? Headlights? Does it happen at night and day? Does it happen when going uphill or down?

Just a short list of what must be provided so that a mechanic can really do his job. A problem because most people cannot bother to collect facts or make the problem reproducible. And because so many people only get angry when asked question after question. So many want intermittent problems solved immediately.

So a mechanic (if not provided an oscilloscope and without information on how to make the problem reproducible) can only keep replacing parts until something works - shotgunning. That will be the solution here.

Check list said if the IACV is not constantly failed, then replace the computer. Check list procedure does not address an IACV failure that occurs, for example, only as the engine gets warm. Only way a mechanic can find / fix that problem is if a person / driver volunteers that fact.

Cloud 04-21-2010 11:51 AM

car is back at mechanic. I asked him why didn't he check the Idle Air Control Valve--and he said he did. He said he checked the circuits along the system, manipulated the valve by hand, etc.

So, we'll see. I can't get my inspection sticker with the car like that.

Undertoad 04-21-2010 11:57 AM

I am shocked SHOCKED that the mechanic performed the checks that tw repeatedly complained he must not have done.

Shawnee123 04-21-2010 12:00 PM

He SAID he performed the checks. How is Cloud to verify that? Guy was like (thought bubble) "hmmm, some friend told her to ask blah blah blah..." (speak bubble) "SURE MA'AM, I did that!"

;)

skysidhe 04-21-2010 12:23 PM

The mystery unfolds.

Cloud 04-21-2010 12:30 PM

Well, I pretty much believe him. He described what he did in much more detail than I put down. And how is anybody supposed to verify actions like that, anyhow?

Shawnee123 04-21-2010 12:32 PM

omg

Again, bad joking on my part.

I'm gonna quit for the day (well, probably not.) :)

Cloud 04-21-2010 12:34 PM

Well, I can ask. I can ask for the parts that were replaced. I can read the description on the invoice. But otherwise, I pretty much have to take their word for it. Do you have a better idea?

Shawnee123 04-21-2010 12:37 PM

No I don't have a better idea.

Sigh.

Mostly, I get so sick of everyone waiting around like spiders for any slip-up they perceive from tw...no, not you. So, it followed that mechanic man said "yeah" and...

Nebber mind, again.

Cloud 04-21-2010 12:40 PM

spiders! spiders! get them OFF me!

(runs screaming into the night. . . . okay, the afternoon)

Flint 04-21-2010 12:48 PM

Put some electrical tape over the little lights on your dashboard.

Issue resolved 04/21/2010. Left vm for customer, no cb. Closing ticket.

Cloud 04-21-2010 01:00 PM

that would be nice, if 1) the engine wasn't acting up; and 2) I didn't have the inspection sticker problem

guy called and said that he's still getting the same code, and so he's ordered ANOTHER PCM to be installed next week. I guess we can only try, but I'm feeling very discouraged.

tw 04-21-2010 02:20 PM

Quote:

Originally Posted by Undertoad (Post 650608)
I am shocked SHOCKED that the mechanic performed the checks that tw repeatedly complained he must not have done.

He did what I posted and did not do what I suggested. Please read what was posted.

Problem is intermittent. If an intermittent IACV, then he did nothing to identify a sticky, temperature sensitive IACV. He did what a diagnostics chart says to identify a constant (hard) failure. Apply voltage. Hear it click. But this is not a hard failure. A valve failing as I have suggested will always pass that test and continue to fail intermittently.

What UT did not read. An IACV works by opening and closing quickly. So fast that only an oscilloscope can see that timing. Did you read the word ‘oscilloscope’? Now read what was posted and tell us the mechanic did what was suggested.

Computers rarely fail. And do not fail only when an engine is warming up. Valves that fail only during warm up do so intermittently. Which part more likely causes an intermittent?

My second point that UT did not read: Mechanic is now doing only what he understands - shotgunning. Just keep replacing parts until something works. He reloaded software. No change. Replaced the computer. No change. So he is replacing the computer again without any reason to believe it is bad. At what point does it become obvious that the computer probably is not a problem? He has resorted to the “I don’t have a clue” option. Shotgunning because he has no idea what else to do.

The best part to shotgun is the one most likely to cause this type of intermittent (heat related) failure. What was posted, and not what UT read. UT go find a paragraph that includes the word oscilloscope. Now read this time what was posted.

Well, he is replacing a second computer - for free. If that does nothing, he should then shotgun the part that was more likely defective - an IACV. I put an IACV at about 65% likely to solve the problem - which is why I so dislike shotgun solutions.

Cloud 04-21-2010 03:11 PM

which is why I so dislike car problems. blecch!

Undertoad 04-21-2010 03:24 PM

Very well, sir, we don't know what he meant by "check voltages". But I'd wager he did what the service manual told him to do.

tw 04-21-2010 09:19 PM

Quote:

Originally Posted by Undertoad (Post 650670)
Very well, sir, we don't know what he meant by "check voltages".

'Check voltages' is about disconnecting the valve from its connector. Then measuring voltage on that connector. It says power is provided to the valve. We already know that. The valve works most of the time. That measurement does nothing to find an intermittent - only identifies a constant failure.

Moving on to what is known - new information for Cloud. IACV fully opens when the car starts. That is why a car is started without pressing the accelerator. The IACV valve does that automatically. If the IAC valve does not open, then the car would not idle at a higher rev - ie 1200 RPM. Therefore that valve operated normally when the car first started.

As the car gets warm, the valve remains mostly closed. But if a warming valve gets stuck, then the car will run rough (too lean) until that unpowered valve eventually frees itself; and closes.

Of course a fully depressed accelerator would make that stuck valve ‘not apparent’. So yes, what is done to make ‘roughness’ no longer happen would be a critically important symptom.

Cloud 05-06-2010 01:21 PM

yep, it's still on. After a computer update; then a replacement; then a replacement for the replacement.

I have very few options. I can keep throwing money at it, (and NO, sorry, I'm not going to start messing around under the hood myself) and hope someone can fix it. Or I can just drive it until it dies, until I need my new inspection sticker (in August), or I feel ready to get a new car.

54,000 miles. bugger.

jinx 05-06-2010 02:14 PM

Quote:

54,000 miles. bugger.
Holy crap, I've got more on my jeep...

Cloud 05-06-2010 02:25 PM

yeah. Makes it harder to get a good used trade in.

lumberjim 05-06-2010 02:41 PM

take the bulb out, and trade it in

classicman 05-06-2010 02:59 PM

^^listen to Jim^^

lumberjim 05-06-2010 03:28 PM

I was kidding

Cloud 05-06-2010 03:34 PM

sounds like a good idea to me. except for the fraud part.

tw 05-06-2010 06:14 PM

Quote:

Originally Posted by Cloud (Post 654250)
sounds like a good idea to me. except for the fraud part.

and they still did not replaced the part that the computer says is defective? The Idle Air Control Valve.

Cloud 07-15-2010 07:33 PM

well, after three months and over $1300, I may have a fix. I had the "throttle body assembly" replaced. No light for two days--keep your fingers crossed!

classicman 07-15-2010 08:14 PM

:fingerscrossed:

tw 07-15-2010 11:51 PM

Quote:

Originally Posted by Cloud (Post 670899)
I had the "throttle body assembly" replaced.

Idle Air Control Valve is part of the replaced throttle body assembly. Who decided to replace it?

Did they reinburse you from the four replaced computers?

Cloud 07-16-2010 08:33 AM

took it back to the dealer. I think I made such a stink about the computer, someone finally decided to look for other causes. Sadly, no reimbursement, because that was from a different mechanic.

whether or not the pcm was necessary, I probably saved money in the long run, because I feel the dealer would have replaced the computer first also, at a higher cost.

and I'm not 100% positive yet it's fixed. we'll see.

skysidhe 07-16-2010 08:59 AM

I once asked the dealer if I could put a locking gas cap on my car. The mechanic told me changing my gas cap would result in the check engine light always being on.


http://autorepair.about.com/od/troub...ghtarticle.htmCHECK ENGINE. There's nothing fun about those two words. There's also not a lot of logic to be gathered from them. Check engine? Could they be a little more specific? Nope, they can't. That's because the Check Engine light comes to life if anything, and we do mean anything isn't 100% under the hood. This means that you could be staring at a major repair, or your gas cap could be too loose (no kidding).


I have my fingers crossed for you cloud!
oh and P.S.

When the mechanics did a OBD scan what was the code?

Cloud 07-16-2010 12:58 PM

the code was P1519 I believe. still not on today, yay!

classicman 07-16-2010 01:49 PM

Try this thread

tw 07-16-2010 05:50 PM

Quote:

Originally Posted by skysidhe (Post 670976)
That's because the Check Engine light comes to life if anything, and we do mean anything isn't 100% under the hood.

The P1519 code says only three things can cause the failure. Computer. Wire. Idle Air Control Valve. So the mechanic kept replacing computers. Never replaced the most likely reason for failure - IACV.

Replacing a throttle body replaces the IACV.

classicman 07-16-2010 09:31 PM

Quote:

Originally Posted by tw (Post 671038)
Replacing a throttle body replaces the IACV.

And possibly other issues that may have caused that code?
Even if not, they make more by keeping the "one fix" part in stock and get the customers car on the road faster.

skysidhe 07-16-2010 09:38 PM

Quote:

Originally Posted by Cloud (Post 671011)
the code was P1519 I believe. still not on today, yay!

great! yay...


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