Am I being shafted by my mechanic?

Ushm

I have a 1.4 TSI VW Passat (petrol) and it failed the NCT on emissions, the lambda reading was 1.33. I brought it in to a garage, they did a diagnostic and told me both lambda sensors were faulty and would need to be replaced. Came to 330 euro for parts and labour (labour was about 50 quid). I then brought the car back to the NCT and it failed again on the exact same thing. This time the lambda reading was 1.35, the NCT mechanic was of the opinion the fault must be somewhere else.
I called the garage, they said that they tested the sensors, the main one was giving a faulty reading and the second one was giving no voltage reading at all so they both had to be replaced. They ran a diagnostic after they were replaced and they were working properly.
Now they want the car back to investigate further. What I want to know is what should I do here? Part of me thinks I should insist they put the old sensors back in but I don't know if I'm within my rights to demand that? Surely they should have got the car to pass the NCT which is why I brought the car to them in the first place?

Toyotafanboi

An NCT lambda fail is rarely caused by a faulty lambda sensor in my experience and the chances of both sensors having fully failed at the same time is also quite unlikely, what's even more unlikely again is that both sensors fully failed and neither brought on the check engine light. Does the car feel like it's running ok because that reading is very bad, i'd expect the cause of that to be fairly obvious.

I'm taking a bit of a Saturday morning leap here but my gut is the mechanic hasn't a notion what's actually wrong with your car and was just hoping for the best. Cowboys often find emissions fixes difficult but a good mechanic should be able to sort your car without too much issue. It'll be a nightmare, if almost impossible to get your money back though.

TomOnBoard

Your mechanic diagnosed that replacement of faulty sensors would solve the problem. It didnt! Therefore none of his efforts worked and the evidence suggests that he misdiagnosed tbe sensors as being faulty when in fact they were not. You paid him €300+. So he now needs to return the car to the condition it was in and refund you in full so that you can bring it to a garage that knows what its doing.

ml100

Very little chance of getting your money or old sensors back, don't waste any more time with someone who doesn't know what they are doing, take the car to a garage that can test emissions.

TomOnBoard

ml100 wrote: »

Very little chance of getting your money or old sensors back, don't waste any more time with someone who doesn't know what they are doing, take the car to a garage that can test emissions.

Well, many ppl wouldnt be able to glide past a €330 bill so easy, and that's not to mention the wasted NCT re-test fee, and the cost of the next garage who will have to sort this out. I certainly would be raising Cain back with that fella and wouldnt be quite as forgiving as suggested.

OP asked if hewas being shafted! Yes, he was!

Stoolbend

Dont bring a car to have the emissions sorted if the garage cant test the emissions.

bucketybuck

TomOnBoard wrote: »

Your mechanic diagnosed that replacement of faulty sensors would solve the problem. It didnt!

Reasonable so far.

Therefore none of his efforts worked and the evidence suggests that he misdiagnosed tbe sensors as being faulty when in fact they were not.

Actually no, none of us can say that. I have seen literally thousands of examples of finding faulty sensors when trying to diagnose deeper fuel/oil/brake/suspension faults. I have often replaced faulty sensors and then continued searching for the deeper issues, such as the short circuit that faulted that sensor in the first place.

I have no wish to defend the garage, my point is simply that it is impossible to state definitively that the garage replaced perfectly good sensors.

You paid him €300+. So he now needs to return the car to the condition it was in and refund you in full so that you can bring it to a garage that knows what its doing.

Good luck with that.

OP, you may not wish to deal with this garage again but I would be aware that it could be very difficult to regain your costs from them, they can mount a plausible defense if you tried to litigate. Before jumping to blood and thunder I would think about if its worth just talking to them and giving them the chance to rectify the situation.

dense

bucketybuck wrote: »

I have no wish to defend the garage, my point is simply that it is impossible to state definitively that the garage replaced perfectly good sensors.

The garage should have explained this prior to doing the work.



The customer has a legitimate expectation that a repair will be a repair and not an expensive experiment.

bucketybuck

dense wrote: »

The garage should have explained this prior to doing the work.



The customer has a legitimate expectation that a repair will be a repair and not an expensive experiment.

That is unfortunately too simplistic. When it comes to interconnected systems everything is an experiment, the idea that dealers can plug in a computer and instantly identify the causal part is pretty much a myth. And one of the biggest struggles garages face is the customers expectations, and the sad fact that they are frequently not based in reality.

The car was brought in with high readings from the lambda sensors. They test both sensors, one gives a faulty reading and the other no reading at all. It is perfectly logical to suspect that the sensors are faulty, they inform the OP of this and then they replace the sensors. They retest the sensors and are happy with the readings.

I repeat, a diagnostic says the sensors are faulty, they replace the sensors, now the diagnostic says everything is now ok. Assuming all of that, why would the garage go any further?

Again, I don't want to defend the garage, no voltage reading at all may have been a red flag. But I can understand their dilemma. A fault is reported, they find a likely cause and fix it, the car now seems to be working ok and passes the diag tests. Do customers really want to pay for labour past that point?

As noted a problem was that they couldn't test the emissions themselves, but then that isn't too unusual, many smaller garages can't afford all the equipment so you get what you pay for there.

The garage is always the bad guy, we all know that. But the OP should consider this, its very plausible that no matter what garage they brought that car to, that those sensors would have been replaced. Even the best garage in the world may have tested those sensors, found them faulty and had to replace them so that they could continue testing for the root cause without the faulty sensors fouling up all the tests.

Thats why its the wrong path going in and demanding they refit your old sensors and refund your money. Even if they can refit them, what if they do and then you bring the car to somebody else who tells you the lambda sensors are faulty?

TomOnBoard

bucketybuck wrote: »

That is unfortunately too simplistic. When it comes to interconnected systems everything is an experiment, the idea that dealers can plug in a computer and instantly identify the causal part is pretty much a myth. And one of the biggest struggles garages face is the customers expectations, and the sad fact that they are frequently not based in reality.

The car was brought in with high readings from the lambda sensors. They test both sensors, one gives a faulty reading and the other no reading at all. It is perfectly logical to suspect that the sensors are faulty, they inform the OP of this and then they replace the sensors. They retest the sensors and are happy with the readings.

I repeat, a diagnostic says the sensors are faulty, they replace the sensors, now the diagnostic says everything is now ok. Assuming all of that, why would the garage go any further?

Again, I don't want to defend the garage, no voltage reading at all may have been a red flag. But I can understand their dilemma. A fault is reported, they find a likely cause and fix it, the car now seems to be working ok and passes the diag tests. Do customers really want to pay for labour past that point?

As noted a problem was that they couldn't test the emissions themselves, but then that isn't too unusual, many smaller garages can't afford all the equipment so you get what you pay for there.

The garage is always the bad guy, we all know that. But the OP should consider this, its very plausible that no matter what garage they brought that car to, that those sensors would have been replaced. Even the best garage in the world may have tested those sensors, found them faulty and had to replace them so that they could continue testing for the root cause without the faulty sensors fouling up all the tests.

Thats why its the wrong path going in and demanding they refit your old sensors and refund your money. Even if they can refit them, what if they do and then you bring the car to somebody else who tells you the lambda sensors are faulty?

I get your point and I see your arguments which are very well made.

However, I cant accept them for the following reason:

The Garage took on a task to resolve a Lambda 1.33 reading issue. He should have told OP: "Sorry, we don't have the equipment to diagnose emission symptoms such as out of whack Lambda". Instead, he diagnosed a set of problems that needed €330 to resolve. But because he did not have the capability to assess whether his 'surgery' resolved the problem, he sent OP merrily on his way, €330 lighter to a re-test that basically said "you've changed nothing- our original assessment as to Lambda readings still stand.

He should have known his limitations (basically a lack of necessary equipment) and ought not have thrown the dice hoping that his own narrow abilities would resolve the problem. He put OP's €330 on 7 and rolled snake-eyes. And OP wasn't even at the table!

Now, lets be clear: if Op went to the garage and said "can you check my Lambda sensors 'coz the NCT says they're faulty.." its on the OP.

However, if OP said "NCT says my Lambda is reading 1.33; are you able to deal with/resolve that?", then it'[s on the Garage.

dense

bucketybuck wrote: »

That is unfortunately too simplistic. When it comes to interconnected systems everything is an experiment, the idea that dealers can plug in a computer and instantly identify the causal part is pretty much a myth. And one of the biggest struggles garages face is the customers expectations, and the sad fact that they are frequently not based in reality.

The car was brought in with high readings from the lambda sensors. They test both sensors, one gives a faulty reading and the other no reading at all. It is perfectly logical to suspect that the sensors are faulty, they inform the OP of this and then they replace the sensors. They retest the sensors and are happy with the readings.

I repeat, a diagnostic says the sensors are faulty, they replace the sensors, now the diagnostic says everything is now ok. Assuming all of that, why would the garage go any further?

Again, I don't want to defend the garage, no voltage reading at all may have been a red flag. But I can understand their dilemma. A fault is reported, they find a likely cause and fix it, the car now seems to be working ok and passes the diag tests. Do customers really want to pay for labour past that point?

As noted a problem was that they couldn't test the emissions themselves, but then that isn't too unusual, many smaller garages can't afford all the equipment so you get what you pay for there.

The garage is always the bad guy, we all know that. But the OP should consider this, its very plausible that no matter what garage they brought that car to, that those sensors would have been replaced. Even the best garage in the world may have tested those sensors, found them faulty and had to replace them so that they could continue testing for the root cause without the faulty sensors fouling up all the tests.

Thats why its the wrong path going in and demanding they refit your old sensors and refund your money. Even if they can refit them, what if they do and then you bring the car to somebody else who tells you the lambda sensors are faulty?

It's not about refitting the old sensors, at least it shouldn't be.


You are attempting to place responsibility on the customer for poor design leading to difficult if not impossible fault diagnoses.



They are relying and paying for professional advice and are not concerned about how the thing works, actually, that has nothing to do with them.



The customer is not supposed to be part of any garage's learn as you go, might fix your car, might not fix your car system, based around trial and error with hundreds of euros being handed over for the experience.



To counter any potential disagreement, garages should explain that their recommended repair might not be successful and get the customer to enter into any contract on that basis.


If this wasn't done in this case the garage is at fault. It's harsh but it's the only way to prevent this type of thing happening.