Another CGA question - car related.

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Batman

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#1874624 29-Sep-2017 11:36

cadman:

As above, it could be simply a bad connection somewhere like a wire shorting to ground or a cracked joint on a circuit board. I would clear the error code and see if it comes back almost immediately and go from there. Permanent faults are much easier to trace.

Hi I don't mean to hijack, can start a new thread, or pm, but cadman seems very knowledgable!

I have a subaru and the power windows are weird. on the driver control of the 4 windows, they seem to play musical chairs. One switch say driver window won't work (no attempt, ie no mechanical sound heard) for a few weeks, then it would work but the passenger window won't work, then it would migrate to the rear r passenger, now it's the passenger L window that has no connection.

Everytime i take it to the dealer he "resets" it and charges me labour/time. I'm not reseting anything anymore because it will just travel. a bit like a worm inside the car. It's an import so i'm not going to bother the local subaru HQ.

Any ideas?

Sidestep

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#1874633 29-Sep-2017 11:57

Paul1977:

Toyota head office said they won't cover the whole lot, but will contribute $180 towards the cost (which totals $373). The local dealer said the have already cut a little off the labour component, but I couldn't talk them down any further.

Not an awful outcome, but not as good as I hoped.

I'm going to email the CEO of the local Toyota branch and see if they he'd consider sharpening his pencil on the labour a little more. If he does then great, if not then I can live with it.

Interestingly the check engine light has gone out again on it's own, although from experience this has happened with the last 2 that have failed, light goes on and off for a while before staying on constantly.

I'm assuming it's a wideband upstream O2 sensor? If their testing shows failure of this sensor that's what will likely have happened.
When the sensor's signal is outside normal parameters your ECU retains a fault code. Their computer - with the engine running - will confirm the out of range sensor in real time.

I think their contribution towards the replacement - and discount on installation - is a decent goodwill gesture.

The problem is that mileage alone isn't a sole reason for failure. The sensor in your taxi, running non stop 24 hours a day, would likely last longer than one in a vehicle that's stopped and started a lot.
These sensors sit in a very harsh environment - the exhaust flow directly under the engine - and experience huge temperature fluctuations every time the vehicle's shut off and restarted.

The sensors have delicate ceramic chips, very sensitive to both thermal and mechanical shock, and are only designed to operate correctly at high temperatures.
Every time it's started they're rapidly heated to nearly 800°C by a heating element, every time it's shut off they cool back down to ambient temp.
A tiny drop of condensation can crack them, a film of carbon from incorrect fuel or engine mechanical wear and they'll read incorrectly. It's a wonder they last as long and work as well as they do.

I've just replaced a pair of them at 68Km in a Ford (Bosch sensors).
They hadn't failed completely - but were operating out of spec, while just inside the limits at which they'd set a code - causing the vehicle to run too rich, which showed as multiple other faults.

Normally I'd think a part failing at 68Km was faulty, but in this case the vehicle was also 4 years old and had done a lot of stop-start driving. I figure this is a time limited part under those conditions.

Paul1977

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#1874678 29-Sep-2017 13:03

Sidestep:

I'm assuming it's a wideband upstream O2 sensor? If their testing shows failure of this sensor that's what will likely have happened.
When the sensor's signal is outside normal parameters your ECU retains a fault code. Their computer - with the engine running - will confirm the out of range sensor in real time.

I think their contribution towards the replacement - and discount on installation - is a decent goodwill gesture.

The problem is that mileage alone isn't a sole reason for failure. The sensor in your taxi, running non stop 24 hours a day, would likely last longer than one in a vehicle that's stopped and started a lot.
These sensors sit in a very harsh environment - the exhaust flow directly under the engine - and experience huge temperature fluctuations every time the vehicle's shut off and restarted.

The sensors have delicate ceramic chips, very sensitive to both thermal and mechanical shock, and are only designed to operate correctly at high temperatures.
Every time it's started they're rapidly heated to nearly 800°C by a heating element, every time it's shut off they cool back down to ambient temp.
A tiny drop of condensation can crack them, a film of carbon from incorrect fuel or engine mechanical wear and they'll read incorrectly. It's a wonder they last as long and work as well as they do.

I've just replaced a pair of them at 68Km in a Ford (Bosch sensors).
They hadn't failed completely - but were operating out of spec, while just inside the limits at which they'd set a code - causing the vehicle to run too rich, which showed as multiple other faults.

Normally I'd think a part failing at 68Km was faulty, but in this case the vehicle was also 4 years old and had done a lot of stop-start driving. I figure this is a time limited part under those conditions.

I don't know what that means, it is one of the ones that are before the catalytic converter.

The thing is it very often doesn't get driven in the weekend and during the week it is just to and from work on the motorway. So engine normally only started and stopped twice per day. I still think it should have lasted way longer under the circumstances, but I guess will have to chalk it up to bad luck this time.

@Sidestep you also seem to know your stuff. When a check engine light comes on, does it usually stay on until it is manually cleared? The engine light wasn't on this morning, and in the past when these have been replaced the light hadn't been on all the time.

Is it possible that something could have caused the sensor to give an error reading yesterday which has since resolved itself?

Sidestep

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#1874782 29-Sep-2017 14:15

Paul1977:
I don't know what that means, it is one of the ones that are before the catalytic converter.

The thing is it very often doesn't get driven in the weekend and during the week it is just to and from work on the motorway. So engine normally only started and stopped twice per day. I still think it should have lasted way longer under the circumstances, but I guess will have to chalk it up to bad luck this time.

@Sidestep you also seem to know your stuff. When a check engine light comes on, does it usually stay on until it is manually cleared? The engine light wasn't on this morning, and in the past when these have been replaced the light hadn't been on all the time.

Is it possible that something could have caused the sensor to give an error reading yesterday which has since resolved itself?

Yes upstream of the Cat. Don't know the year/model of your car but likely is a wideband (more complicated, measures a wide range of ratios) sensor.
I'm no expert, just fix my own (& friends) vehicles when they have issues, cause I'm too cheap to pay anyone else.

Check engine lights can come on - then go off again when the vehicle has completed a certain number of cycles without the fault recurring. The fault code's held in the computer until it's manually cleared.

When sensors start failing they often show a fault under more 'extreme' conditions at first, then gradually the fault recurs more often until it's completely failed.

Your car's ECU has a fixed set of parameters - a map - that the O2 sensor should read within under normal driving conditions, outside this it records a fault.
With your car plugged in the dealership can see more accurately if the sensor's reading where it should be under fixed conditions such as a certain rpm, temp etc.
Sometimes - like the ones I replaced - they haven't even reached the stage where they register a fault, yet cause the vehicle to run badly.

They're usually right if they say it's failed since they're measuring it's output more accurately than a simple fault/no fault situation.

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#1874786 29-Sep-2017 14:26

Sidestep:

Yes upstream of the Cat. Don't know the year/model of your car but likely is a wideband (more complicated, measures a wide range of ratios) sensor.
I'm no expert, just fix my own (& friends) vehicles when they have issues, cause I'm too cheap to pay anyone else.

Check engine lights can come on - then go off again when the vehicle has completed a certain number of cycles without the fault recurring. The fault code's held in the computer until it's manually cleared.

When sensors start failing they often show a fault under more 'extreme' conditions at first, then gradually the fault recurs more often until it's completely failed.

Your car's ECU has a fixed set of parameters - a map - that the O2 sensor should read within under normal driving conditions, outside this it records a fault.
With your car plugged in the dealership can see more accurately if the sensor's reading where it should be under fixed conditions such as a certain rpm, temp etc.
Sometimes - like the ones I replaced - they haven't even reached the stage where they register a fault, yet cause the vehicle to run badly.

They're usually right if they say it's failed since they're measuring it's output more accurately than a simple fault/no fault situation.

Thanks for that, very informative.

I only called in after work yesterday so the only quickly plugged it into the computer to see the code. I spoke to the service manager today who said the will test it properly when I bring it in.

So, am I correct that an intermittent light (even when it's on) doesn't necessarily mean the sensor has completely failed, just that is is working poorly enough that it should be replaced? I.e. having it in how it is would potentially still be better than driving without it, or with a completely failed one?

ArcticSilver

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#1874797 29-Sep-2017 14:45

I have dealt with sensor issues on my Toyota as well, personally I imported a replacement sensor and fitted it myself. From memory this cost less than $60. You can import genuine ones too for less than $100 and (at least on my car) it was 2 screws, unplug, screw in and replug the replacement, a 5min job. I would highly recommend this if you're facing a $100+ bill.

You can also get a cleaner to clean the sensor, this might be worth a shot first as a possible quick fix.

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#1874798 29-Sep-2017 14:50

Paul1977:

Thanks for that, very informative.

I only called in after work yesterday so the only quickly plugged it into the computer to see the code. I spoke to the service manager today who said the will test it properly when I bring it in.

So, am I correct that an intermittent light (even when it's on) doesn't necessarily mean the sensor has completely failed, just that is is working poorly enough that it should be replaced? I.e. having it in how it is would potentially still be better than driving without it, or with a completely failed one?

Ah.. I thought the dealership had confirmed it was a failed sensor.

As cadman said earlier without a definite diagnosis it could still be something as simple as the plastic connector not properly snapped in after your previous replacement.
If it's still working and only an intermittent fault you may not notice much difference yet.

Completely failed or out of whack you'll likely find your car's running too rich, which would cause a mileage drop and damage to the cat if driven too long without repair.
They're usually set to go rich on failure, because failing lean could overheat the engine & potentially wreck the car.

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#1874802 29-Sep-2017 14:57

ArcticSilver:

I have dealt with sensor issues on my Toyota as well, personally I imported a replacement sensor and fitted it myself. From memory this cost less than $60. You can import genuine ones too for less than $100 and (at least on my car) it was 2 screws, unplug, screw in and replug the replacement, a 5min job. I would highly recommend this if you're facing a $100+ bill.

You can also get a cleaner to clean the sensor, this might be worth a shot first as a possible quick fix.

Yep they're not hard to replace. Correctly diagnosing the fault can be hard...

I got in 2 OEM sensors for $US32 ea (as opposed to $200 + over here)

Paul1977

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#1874880 29-Sep-2017 17:19

Sidestep:

Ah.. I thought the dealership had confirmed it was a failed sensor.

As cadman said earlier without a definite diagnosis it could still be something as simple as the plastic connector not properly snapped in after your previous replacement.
If it's still working and only an intermittent fault you may not notice much difference yet.

Completely failed or out of whack you'll likely find your car's running too rich, which would cause a mileage drop and damage to the cat if driven too long without repair.
They're usually set to go rich on failure, because failing lean could overheat the engine & potentially wreck the car.

The fault code said it was the sensor, and while they said they will test it more when I bring it in he indicated that there wasn't really anything else it could be.

EDIT: They have ordered the part and spoken to Toyota head office about the discount, so I assume are already confident it is the sensor.

Paul1977

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#1874886 29-Sep-2017 17:33

ArcticSilver:

I have dealt with sensor issues on my Toyota as well, personally I imported a replacement sensor and fitted it myself. From memory this cost less than $60. You can import genuine ones too for less than $100 and (at least on my car) it was 2 screws, unplug, screw in and replug the replacement, a 5min job. I would highly recommend this if you're facing a $100+ bill.

You can also get a cleaner to clean the sensor, this might be worth a shot first as a possible quick fix.

The O2 sensor on the other side failed about 4 years ago, at the time Toyota quoted a crazy price so I imported one myself instead. But it was just in too awkward a position and I didn't have the right tools to do it myself, so had to get the dealer to fit it for me.

The part from Toyota is $245 with them paying $180 of that, so the part itself is only costing me $65. Shame about the labour cost involved, but I just don't think I can do it myself.

Paul1977

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#1876655 3-Oct-2017 13:54

I spoke with the dealership manager and they went back to Toyota NZ again who have now agreed to pay the full cost of replacement (including labour), so I'm very pleased with that outcome.

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