Is my mechanic telling me the truth?

[laserx]

A month ago I got CE light on, had it checked and it came up knock sensor and 02 sensor 3 I believe (it's the 02 senor on the exhaust pipe after the engine), both were replaced at the Subaru Dealer. Anyway, after a week CE came back on, I took it back and he cleared the CE a week later it came back. I then left my car with them as I went on a holiday for two weeks with instruction to fix everything they could find wrong. Over $2000.00 later I picked up my car all was perfect...for 9 days and once again CE light same 02 senor. I'm thinking I have a defective 02 sensor, the mechanic now says it must be the MAF causing the 02 senor fault to show up and they want over $500.00 for the part. I still think they should try another 02 sensor before I shell out $500.00 for the MAF. My question, is the mechanic right and should I just go for the new MAF or should I insist on trying a new 02 sensor first. (anyone got a used MAF for sale?)

Oh ya to add to this, my transmission has now gone insane, works perfect sometimes and sometimes will not shift up into 4th gear, just rev's like crazy, it's going into the transmission shop on Friday.

[SoCal LS-L]

I highly doubt its the MAF. What brand O2 sensor did they install? It makes a huge difference if its not OEM, or at least a good import brand like NGK. There could also be an issue with the wiring... my advice is take it to someone else who knows what they are doing.

[kwren]

Sorry, you got screwed big time. Mechanics do not know the truth or how to find it... If you can't work out what your car needs with help from the people on this form, you have no chance.

That obscene bill had nothing to do with rectifying your car problem. Sanity dictates that if it did, the car would not still be doing the same thing.

So sorry...

Keith

[kwren]

An 02 sensor code seldom comes in conjunction with an actual 02 sensor failure. That code is like a "catch all" thing.

Keith

[Trevor]

Originally Posted by kwren

An 02 sensor code seldom comes in conjunction with an actual 02 sensor failure. That code is like a "catch all" thing.

Keith

Codes 32 & 37 specifically indicate an actual sensor failure or a failure in associated wiring or connections. "Catch all" posts may provide satisfaction for writer, but are detrimental and cause confusion.

The sensor and wiring can be easily tested, provided that the technician involved knows what he is about.

[Cam]

Originally Posted by Trevor

Codes 32 & 37 specifically indicate an actual sensor failure or a failure in associated wiring or connections. "Catch all" posts may provide satisfaction for writer, but are detrimental and cause confusion.

The sensor and wiring can be easily tested, provided that the technician involved knows what he is about.

+1 If the code keeps popping up then something in the circuit related to the 02 sensor is not right. You can trace the wire through the harness yourself if your patient, looking for obvious signs of abuse/damage (melted wires, pinched bundles, etc.). And by the way, a good mechanic that knows the SVX well will be able to diagnose specific problems, regardless of him being a member to an internet forum.

You can replace the 02 sensor yourself quite easily, and unplug your battery for 30+ minutes to reset your ECU and clear your codes.

[TomsSVX]

Originally Posted by laserx

A month ago I got CE light on, had it checked and it came up knock sensor and 02 sensor 3 I believe (it's the 02 senor on the exhaust pipe after the engine), both were replaced at the Subaru Dealer. Anyway, after a week CE came back on, I took it back and he cleared the CE a week later it came back. I then left my car with them as I went on a holiday for two weeks with instruction to fix everything they could find wrong. Over $2000.00 later I picked up my car all was perfect...for 9 days and once again CE light same 02 senor. I'm thinking I have a defective 02 sensor, the mechanic now says it must be the MAF causing the 02 senor fault to show up and they want over $500.00 for the part. I still think they should try another 02 sensor before I shell out $500.00 for the MAF. My question, is the mechanic right and should I just go for the new MAF or should I insist on trying a new 02 sensor first. (anyone got a used MAF for sale?)

Oh ya to add to this, my transmission has now gone insane, works perfect sometimes and sometimes will not shift up into 4th gear, just rev's like crazy, it's going into the transmission shop on Friday.

This was on the 96?? You stated that the tech changed 2 02 sensors. Problem is, there are 3 in the OBDII system. The third is above the rear end of the catalytic converter. Ask the tech for the exact code which is reoccurring. I vaguely remember the rear 02 sensor description made me want to believe it was the left front.


Tom

[Trevor]

Originally Posted by TomsSVX

This was on the 96?? You stated that the tech changed 2 02 sensors. Problem is, there are 3 in the OBDII system. The third is above the rear end of the catalytic converter. Ask the tech for the exact code which is reoccurring. I vaguely remember the rear 02 sensor description made me want to believe it was the left front.

Tom

Thanks Tom,

By way of trying to be of help (N.B. Keith.) in view of the page change, I am hereby making sure that your important advice does not become buried among the preceding superfluous stuff.

[sowise]

Trevor, here is how I see the original statement and why I must still disagree with you.

A month ago I got CE light on, had it checked and it came up knock sensor and 02 sensor 3 I believe (it's the 02 sensor on the exhaust pipe after the engine), both were replaced at the Subaru Dealer.

The "I believe" is a him adding in a bit of uncertainty because he is referencing either something he was told, or what he believes based on perhaps limited knowledge. His description of the location of the sensor kind of helps support that. While it wasn't something worth correcting because it isn't entirely wrong but not entirely correct either.

then i posted all of the OBDII codes for a 96 and newer subaru, that were O2 related. There isn't anything that says "sensor is bad". For all we know both codes could have been caused by his knock sensor. He could have been running lean causing a knock and not have had to replace either sensor, because his catalytic efficiency readings wouldn't be accurate. If he had his exhaust recently done then it could have a leak, he could have a vacuum leak because they may have pulled his intake to do the knock sensor. I still disagree with taking a car to a shop with a CE lit they reset it and send you on your way. I think that is wrong. You can get that done free at most autoparts shops. Hopefully they didn't charge him for that. I think everyone intends to help but with an intermittent problem it is a wild goose chase in some respects. If you look at all the potential causes for the P1151 which I was using as an example because it was the a rear sensor fault code. But I think so far everyone who suggested something could be found in the list of possibles.
I am not disagreeing with you to pick on you or because I want to be an ass. I don't, however you give the impression that your way is the only way. A description given of what another tech is doing with their car is usually going to have some kind of details missing.

[Trevor]

sowise

You hold the advantage of addressing me in person, from a position of obscurity.

You acknowledge, --- “I think everyone intends to help but with an intermittent problem it is a wild goose chase in some respects.”

It is my opinion that the goose described is far too wild and chasing it ahead of a more logical approach is not good advice for laserx to follow, particularly as he is paying for the work involved. N.B. e.g. the now concealed post #15, inserted by Tom.

It is unfortunate that in your view, putting forward an opinion backed with evidence, gives the impression that my intent is indicate that my way is the only way, when the real object is to emphasise what is best in the interests of the person requiring assistance.

[kwren]

Originally Posted by Trevor

It is unfortunate that in your view, putting forward an opinion backed with evidence, gives the impression that my intent is indicate that my way is the only way.

I think that statement should read... "in everyone's view". Pushing as gospel your "limited expertise" as the "only thing" does indicate exactly what you think it indicates... "your way is the only way".

Keep in mind that you are not unique, Trevor. Nobody on earth knows everything and it is futile to try to convince people that you do.

Keith

[sowise]

Originally Posted by Trevor

sowise

You hold the advantage of addressing me in person, from a position of obscurity.

What is that even supposed to mean or refer to?

Originally Posted by Trevor

You acknowledge, --- “I think everyone intends to help but with an intermittent problem it is a wild goose chase in some respects.”

It is my opinion that the goose described is far too wild and chasing it ahead of a more logical approach is not good advice for laserx to follow, particularly as he is paying for the work involved. N.B. e.g. the now concealed post #15, inserted by Tom.

I think I gave a good example of why it is a wild goose chase, one code for the rear sensor could be cause by numerous systems operating incorrectly. My suggestions were simple easy to do and didn't really require tools or anything beyond basic knowledge. I will rarely recommend to people without knowledge of their skill level to get a multimeter and do continuity checks or check for voltage. Most people don't even have a multimeter and some don't know how to use it. Visual inspections are to look for the obvious, when nothing obvious can be found then you go deeper. How is that not logical? My approach would not have cost him money. It was a check this check that and btw how about some more info.

Originally Posted by Trevor

It is unfortunate that in your view, putting forward an opinion backed with evidence, gives the impression that my intent is indicate that my way is the only way, when the real object is to emphasise what is best in the interests of the person requiring assistance.

My opinion backed with evidence? I gave suggestions backed by facts to support. Your suggestion is backed in what I provided as well, you should be happy.

Originally Posted by Trevor

It is a fact that a registered fault code specifically covering an individual sensor, is confined to a fault within that component or associated circuitry. The code does not indicate that the sensor is signalling a fault condition which it is correctly detecting. This is a matter which requires no specific expertise, no unique understanding, involves only common sense and does not amount to a personal opinion.

Yes, it registered a fault code causing the CE, you don't know the code so how can you even say what it is or isn't doing? Let alone what sensor it actually was. All fault troubleshooting involves common sense, none of the suggestions I saw were personal opinion they were based on personal experiences with peoples own vehicles and similar code situations. Unless you see suggestions as opinions. It's the only way I can make sense of your responses.

I apologize to Laserx for turning this thread into a back and forth verbal spat. Hopefully we will hear something about how it is fixed and running great with no CE, for little to no new cost.

[lhopp77]

Originally Posted by TomsSVX

This was on the 96?? You stated that the tech changed 2 02 sensors. Problem is, there are 3 in the OBDII system. The third is above the rear end of the catalytic converter. Ask the tech for the exact code which is reoccurring. I vaguely remember the rear 02 sensor description made me want to believe it was the left front.


Tom

+1. Also, my son ordered a Stebro high flow cat for his 97. When it came, it had the O2 sensor bung in the front end of the cat--wrong place for the 96 or 97. I had to have that bung filled and another installed at the back end of the cat. If you have the Stebro hi-flow cat, you might check.

Lee

[Trevor]

Originally Posted by lhopp77

+1. Also, my son ordered a Stebro high flow cat for his 97. When it came, it had the O2 sensor bung in the front end of the cat--wrong place for the 96 or 97. I had to have that bung filled and another installed at the back end of the cat. If you have the Stebro hi-flow cat, you might check.

Lee

Kioa ora Lee,

I am sincerely sorry to have in any way have obscured your valuable contribution. Therefore it is again reproduced above, in its rightful order.

Trevor.

[Cam]

laserx, did you resolve your issue with the CE light yet?