Potential warranty issue - how to approach?
Discussion
Hi folks,
I have an issue with a Mazda purchased with 'Mazda Used Approved' warranty.
The engine light came on and a P0421 code has been generated and I'm reading online this often points to catalytic convertor failure. It can be something minor like a frayed O2 sensor cable or exhaust leak, but this seems uncommon. I've not noticed any issues when driving.
The rep at the local Mazda dealership asked me to clear the code see if it comes back (not sure if this was good advice) and booked the car in "to have a look".
Having had a read about P0421 I think it needs more than a quick look.
This is the fist time I've bought a car from a dealership can anybody advise how to approach this issue?
As far as warranty goes, I see this exclusion from the handbook : Catalytic converters (except in the case of internal failure or failure to meet emission requirements under government legislation).
I'm not sure what else but "internal failure" can cause catalytic convertor failure?
The car has done <60k btw
Thanks for reading..
I have an issue with a Mazda purchased with 'Mazda Used Approved' warranty.
The engine light came on and a P0421 code has been generated and I'm reading online this often points to catalytic convertor failure. It can be something minor like a frayed O2 sensor cable or exhaust leak, but this seems uncommon. I've not noticed any issues when driving.
The rep at the local Mazda dealership asked me to clear the code see if it comes back (not sure if this was good advice) and booked the car in "to have a look".
Having had a read about P0421 I think it needs more than a quick look.
This is the fist time I've bought a car from a dealership can anybody advise how to approach this issue?
As far as warranty goes, I see this exclusion from the handbook : Catalytic converters (except in the case of internal failure or failure to meet emission requirements under government legislation).
I'm not sure what else but "internal failure" can cause catalytic convertor failure?
The car has done <60k btw
Thanks for reading..
Ah yes, the good old alarmist fault codes! Not so long ago I had a car that threw up a whole series of fault codes relating to cruise control failure, ABS failure and a whole host of other things. Dim-witted dealer had me believing I was looking at thousands of pounds to replace the ABS pump, the drive-by-wire potentiometer on the accelerator, the speedometer (which had stopped working) and a whole host of other expensive parts.
Turned out to be a split reluctor ring on one of the half shafts. Speed senor data was absent at that corner so all speed-related functions had been shut down by the ECMs. New ring and fitting was less than £50.
One of the standard methods of fault diagnosis is to clear a code and see how quickly it returns and under what circumstances, BTW. My advice is don't panic and apply some critical thinking to the issue. Give the dealer a chance to check things like the 02 sensors and gaskets. If the cat has been poisoned due to the failure of another component that is covered by warranty then you might have a case to argue, but don't go in all guns blazing at this point.
I suspect though that the emissions failure and internal failure inclusions will have you covered though. The warranty terms are protecting the underwriter from situations where the exhaust may have been modified or physically damaged.
Turned out to be a split reluctor ring on one of the half shafts. Speed senor data was absent at that corner so all speed-related functions had been shut down by the ECMs. New ring and fitting was less than £50.
One of the standard methods of fault diagnosis is to clear a code and see how quickly it returns and under what circumstances, BTW. My advice is don't panic and apply some critical thinking to the issue. Give the dealer a chance to check things like the 02 sensors and gaskets. If the cat has been poisoned due to the failure of another component that is covered by warranty then you might have a case to argue, but don't go in all guns blazing at this point.
I suspect though that the emissions failure and internal failure inclusions will have you covered though. The warranty terms are protecting the underwriter from situations where the exhaust may have been modified or physically damaged.
Edited by Evercross on Tuesday 17th May 15:57
SteBrown91 said:
Dont clear the code as you are deleting the fault. Let Mazda dealer with it
Agreed. I had a car purchased under approved used, and whilst the approved used warranty was still valid, I got a check engine light one morning. Drove it straight to the main dealer (not the one I bought the car from), told them I'm not willing to drive it as I don't want to take chances if it's something major and driving would cause it damage. They understood, took it in and arranged a loan car within 2 hours. It's MB so their scheme can be quite good.
Anyway, got a call the next day to say I could pick up my car, it's been fixed, the car just needed a software update for the thermostat (which they applied) and it was all covered under the approved used warranty.
raspy said:
SteBrown91 said:
Dont clear the code as you are deleting the fault. Let Mazda dealer with it
Agreed. I had a car purchased under approved used, and whilst the approved used warranty was still valid, I got a check engine light one morning. Drove it straight to the main dealer (not the one I bought the car from), told them I'm not willing to drive it as I don't want to take chances if it's something major and driving would cause it damage. They understood, took it in and arranged a loan car within 2 hours. It's MB so their scheme can be quite good.
Anyway, got a call the next day to say I could pick up my car, it's been fixed, the car just needed a software update for the thermostat (which they applied) and it was all covered under the approved used warranty.
Evercross said:
Ah yes, the good old alarmist fault codes! Not so long ago I had a car that threw up a whole series of fault codes relating to cruise control failure, ABS failure and a whole host of other things. Dim-witted dealer had me believing I was looking at thousands of pounds to replace the ABS pump, the drive-by-wire potentiometer on the accelerator, the speedometer (which had stopped working) and a whole host of other expensive parts.
Turned out to be a split reluctor ring on one of the half shafts. Speed senor data was absent at that corner so all speed-related functions had been shut down by the ECMs. New ring and fitting was less than £50.
One of the standard methods of fault diagnosis is to clear a code and see how quickly it returns and under what circumstances, BTW. My advice is don't panic and apply some critical thinking to the issue. Give the dealer a chance to check things like the 02 sensors and gaskets. If the cat has been poisoned due to the failure of another component that is covered by warranty then you might have a case to argue, but don't go in all guns blazing at this point.
I suspect though that the emissions failure and internal failure inclusions will have you covered though. The warranty terms are protecting the underwriter from situations where the exhaust may have been modified or physically damaged.
BMW by any chance ? the pick up ring swells up and fools the sensor - usually turning off the traction control will allow you to drive the car.Turned out to be a split reluctor ring on one of the half shafts. Speed senor data was absent at that corner so all speed-related functions had been shut down by the ECMs. New ring and fitting was less than £50.
One of the standard methods of fault diagnosis is to clear a code and see how quickly it returns and under what circumstances, BTW. My advice is don't panic and apply some critical thinking to the issue. Give the dealer a chance to check things like the 02 sensors and gaskets. If the cat has been poisoned due to the failure of another component that is covered by warranty then you might have a case to argue, but don't go in all guns blazing at this point.
I suspect though that the emissions failure and internal failure inclusions will have you covered though. The warranty terms are protecting the underwriter from situations where the exhaust may have been modified or physically damaged.
Edited by Evercross on Tuesday 17th May 15:57
Even if the op doesn't clear the code thats the first thing the dealer is going to do before sending it on its way its too generic.
Thanks for the comments.
Regarding the code I cleared it.. because that's what the dealer recommended.
With hindsight I think with an engine light on they have a formal obligation to investigate? I suspect this as when I was asked if I had Mazda roadside assistance - they said 'oh but if you call them they will just _tow_ the car to us' [because the engine warning light is on]
Watch and wait for the code to reappear might be a fair approach, but it leaves me stressed.
Can this code just come up as a glitch?
How to -politely- make sure a proper diagnostic is done under warranty, or provide me with a job sheet ahead of works?
The language is nice and friendly but ambiguous 'book it in' ... 'we'll take a quick look' etc
They are supposed to be good guys btw.
Regarding the code I cleared it.. because that's what the dealer recommended.
With hindsight I think with an engine light on they have a formal obligation to investigate? I suspect this as when I was asked if I had Mazda roadside assistance - they said 'oh but if you call them they will just _tow_ the car to us' [because the engine warning light is on]
Watch and wait for the code to reappear might be a fair approach, but it leaves me stressed.
Can this code just come up as a glitch?
Starfighter said:
Make sure that the job sheet is clear. "Investigate and correct error code ...." not "Replace / adjust sensor". You will need to have some level of history for the fault and attempts to fix it.
Thank you, can you recommend how to go about this.How to -politely- make sure a proper diagnostic is done under warranty, or provide me with a job sheet ahead of works?
The language is nice and friendly but ambiguous 'book it in' ... 'we'll take a quick look' etc
They are supposed to be good guys btw.
Yes it can be a glitch, we have had couple recently where the codes were random and the only thing in common was supermarket fuel - both petrol cars
The issue you have with main dealers is they will have to follow a set process to diagnose. It might be too late but if it happens just scan it and take a picture for reference.
The issue you have with main dealers is they will have to follow a set process to diagnose. It might be too late but if it happens just scan it and take a picture for reference.
Evercross said:
Ah yes, the good old alarmist fault codes! Not so long ago I had a car that threw up a whole series of fault codes relating to cruise control failure, ABS failure and a whole host of other things. Dim-witted dealer had me believing I was looking at thousands of pounds to replace the ABS pump, the drive-by-wire potentiometer on the accelerator, the speedometer (which had stopped working) and a whole host of other expensive parts.
Turned out to be a split reluctor ring on one of the half shafts. Speed senor data was absent at that corner so all speed-related functions had been shut down by the ECMs. New ring and fitting was less than £50.
One of the standard methods of fault diagnosis is to clear a code and see how quickly it returns and under what circumstances, BTW. My advice is don't panic and apply some critical thinking to the issue. Give the dealer a chance to check things like the 02 sensors and gaskets.
Thanks! Appreciate the calming suggestions. Turned out to be a split reluctor ring on one of the half shafts. Speed senor data was absent at that corner so all speed-related functions had been shut down by the ECMs. New ring and fitting was less than £50.
One of the standard methods of fault diagnosis is to clear a code and see how quickly it returns and under what circumstances, BTW. My advice is don't panic and apply some critical thinking to the issue. Give the dealer a chance to check things like the 02 sensors and gaskets.
Evercross said:
I suspect though that the emissions failure and internal failure inclusions will have you covered though. The warranty terms are protecting the underwriter from situations where the exhaust may have been modified or physically damaged.
Seems to make sense.Proof is in the pudding? I hope to skip desserts!
stevemcs said:
Yes it can be a glitch, we have had couple recently where the codes were random and the only thing in common was supermarket fuel - both petrol cars.
Took on board your previous comment. I'll top up with premium next time.stevemcs said:
The issue you have with main dealers is they will have to follow a set process to diagnose. It might be too late but if it happens just scan it and take a picture for reference.
I do have these, timestamped.
On my E46 with 170,000 miles it is due to cats ageing. A hard fault with wiring would cause another code. I guess in theory an air leak or poor mixture could stop the cats working but imagine you would get a fuel trim code sharpish not a cat efficiency one.
A worn O2 sensor could in theory if the detection system is crude, but I think it less likely, as a good monitoring algorithm will be looking for the point at which the post cat readings start being stable and stop fluctuating a lot in line with the pre-cat lambda readings, once the cats have warmed up and lit off, not just a slightly low or high reading that is stable.
So I would be wondering if cats are a weak point on this model or whether something (wrong fuel or excessive oil burning) had poisoned them. But if under warranty and nothing to lose then I imagine they have to sort it one way or the other.
A worn O2 sensor could in theory if the detection system is crude, but I think it less likely, as a good monitoring algorithm will be looking for the point at which the post cat readings start being stable and stop fluctuating a lot in line with the pre-cat lambda readings, once the cats have warmed up and lit off, not just a slightly low or high reading that is stable.
So I would be wondering if cats are a weak point on this model or whether something (wrong fuel or excessive oil burning) had poisoned them. But if under warranty and nothing to lose then I imagine they have to sort it one way or the other.
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