The MIL has come on again on SWMBO's Yaris. When she started the engine 
this morning, the light failed to go out.

I have read the code and it is 94. The autodata code list I have says that 
this code is for a small fuel system leak. Please can anyone confirm that 
this is correct? Suggested causes are wiring, pressure sensor or mechanical 
fault. With the light on, the car continues to drive as normal. Have 
checked for obvious signs of leaks i.e. wet patches, weeping unions etc and 
found nothing. She last put fuel in on Wednesday but the problem has not 
re-occurred until today (Saturday).

I feel that the problem is likely to be a sensor or calibration issue. Does 
anyone have knowledge of the problem and an easy remedy to suggest or is it 
going to be a trip back to Derby for a warranty repair? BTW, I've already 
reset the ECU once and this has only worked for a few days.



-- 
Stuart Sharp

"Stu"  wrote in message 
news:Xns96BF916BCFD84nobodyhomecom@216.196.109.144...

> The MIL has come on again on SWMBO's Yaris. When she started the engine
> this morning, the light failed to go out.
>
> I have read the code and it is 94. The autodata code list I have says that
> this code is for a small fuel system leak. Please can anyone confirm that
> this is correct? Suggested causes are wiring, pressure sensor or 
> mechanical
> fault. With the light on, the car continues to drive as normal. Have
> checked for obvious signs of leaks i.e. wet patches, weeping unions etc 
> and
> found nothing. She last put fuel in on Wednesday but the problem has not
> re-occurred until today (Saturday).
>
> I feel that the problem is likely to be a sensor or calibration issue. 
> Does
> anyone have knowledge of the problem and an easy remedy to suggest or is 
> it
> going to be a trip back to Derby for a warranty repair? BTW, I've already
> reset the ECU once and this has only worked for a few days.
>


You do have the proper fuel cap, and it is done up the right amount of 
clicks? (if appropriate?)

mrcheerful

"mrcheerful                                                             
            ."  wrote in
news:Ei_Pe.97228$G8.15495@text.news.blueyonder.co.uk: 


> 
> "Stu"  wrote in message 
> news:Xns96BF916BCFD84nobodyhomecom@216.196.109.144...
>> The MIL has come on again on SWMBO's Yaris. When she started the
>> engine this morning, the light failed to go out.
>>
>> I have read the code and it is 94. The autodata code list I have says
>> that this code is for a small fuel system leak. Please can anyone
>> confirm that this is correct? Suggested causes are wiring, pressure
>> sensor or mechanical
>> fault. With the light on, the car continues to drive as normal. Have
>> checked for obvious signs of leaks i.e. wet patches, weeping unions
>> etc and
>> found nothing. She last put fuel in on Wednesday but the problem has
>> not re-occurred until today (Saturday).
>>
>> I feel that the problem is likely to be a sensor or calibration
>> issue. Does
>> anyone have knowledge of the problem and an easy remedy to suggest or
>> is it
>> going to be a trip back to Derby for a warranty repair? BTW, I've
>> already reset the ECU once and this has only worked for a few days.
>>
> 
> You do have the proper fuel cap, and it is done up the right amount of
> clicks? (if appropriate?)
> 
> mrcheerful 
> 
> 

Thanks for the reply, Mr C

It's the original cap, AFAIK. I'll make sure it's tightened up fully. The 
manual just says tighten until it clicks, doesn't mention a specific 
number of clicks. AFAIK, the clicking is just a simple clutch mechanism, 
to prevent overtightening, is it not? Are you thinking that fuel is 
escaping via the filler cap (I feel that this is unlikely), or is there 
some other significance?

FTR, when the MIL came on for the first time, we had yet to refuel it for 
the first time, so I don't think it's just something that just SWMBO is 
doing wrong.



-- 
Stuart Sharp

"Stu"  wrote in message 
news:Xns96BFE1C353721nobodyhomecom@216.196.109.144...

> "mrcheerful
>            ."  wrote in
> news:Ei_Pe.97228$G8.15495@text.news.blueyonder.co.uk:
>
>>
>> "Stu"  wrote in message
>> news:Xns96BF916BCFD84nobodyhomecom@216.196.109.144...
>>> The MIL has come on again on SWMBO's Yaris. When she started the
>>> engine this morning, the light failed to go out.
>>>
>>> I have read the code and it is 94. The autodata code list I have says
>>> that this code is for a small fuel system leak. Please can anyone
>>> confirm that this is correct? Suggested causes are wiring, pressure
>>> sensor or mechanical
>>> fault. With the light on, the car continues to drive as normal. Have
>>> checked for obvious signs of leaks i.e. wet patches, weeping unions
>>> etc and
>>> found nothing. She last put fuel in on Wednesday but the problem has
>>> not re-occurred until today (Saturday).
>>>
>>> I feel that the problem is likely to be a sensor or calibration
>>> issue. Does
>>> anyone have knowledge of the problem and an easy remedy to suggest or
>>> is it
>>> going to be a trip back to Derby for a warranty repair? BTW, I've
>>> already reset the ECU once and this has only worked for a few days.
>>>
>>
>> You do have the proper fuel cap, and it is done up the right amount of
>> clicks? (if appropriate?)
>>
>> mrcheerful
>>
>>
> Thanks for the reply, Mr C
>
> It's the original cap, AFAIK. I'll make sure it's tightened up fully. The
> manual just says tighten until it clicks, doesn't mention a specific
> number of clicks. AFAIK, the clicking is just a simple clutch mechanism,
> to prevent overtightening, is it not? Are you thinking that fuel is
> escaping via the filler cap (I feel that this is unlikely), or is there
> some other significance?
>
> FTR, when the MIL came on for the first time, we had yet to refuel it for
> the first time, so I don't think it's just something that just SWMBO is
> doing wrong.


Lexus (Toyota in disguise) sometimes put  the light on if the cap is not 
tight, they recommend three clicks.  I imagine that it monitors tank 
pressure, which would disappear with a loose cap.

mrcheerful

The rules say that a leak equivalent to a 0.5 mm hole should put the
warning light on. That's pretty imperceptible, and a
not-fully-tightened cap could easily do that. Alternatively, the leak
could be somewhere in the vapour purge system, which would mean it's
not fuel but just fuel vapour that's leaking out (so no sign of liquid
petrol anywhere).

What puzzles me, though, is that I thought these rules only applied to
US-market cars. Even if the Yaris is sold in the US (which seems
unlikely, though I may be wrong), European spec cars typically have
this test disabled. It might be worth re-checking the fault code via
some other reference source to make sure it really is a fuel systsme
leak.

Tony

"mrcheerful                                                             
            ."  wrote in
news:3m7Qe.97563$G8.48867@text.news.blueyonder.co.uk: 


> 
> "Stu"  wrote in message 
> news:Xns96BFE1C353721nobodyhomecom@216.196.109.144...
>> "mrcheerful
>>            ."  wrote in
>> news:Ei_Pe.97228$G8.15495@text.news.blueyonder.co.uk:
>>
>>>
>>> "Stu"  wrote in message
>>> news:Xns96BF916BCFD84nobodyhomecom@216.196.109.144...
>>>> The MIL has come on again on SWMBO's Yaris. When she started the
>>>> engine this morning, the light failed to go out.
>>>>
>>>> I have read the code and it is 94. The autodata code list I have
>>>> says that this code is for a small fuel system leak. Please can
>>>> anyone confirm that this is correct? Suggested causes are wiring,
>>>> pressure sensor or mechanical
>>>> fault. With the light on, the car continues to drive as normal.
>>>> Have checked for obvious signs of leaks i.e. wet patches, weeping
>>>> unions etc and
>>>> found nothing. She last put fuel in on Wednesday but the problem
>>>> has not re-occurred until today (Saturday).
>>>>
>>>> I feel that the problem is likely to be a sensor or calibration
>>>> issue. Does
>>>> anyone have knowledge of the problem and an easy remedy to suggest
>>>> or is it
>>>> going to be a trip back to Derby for a warranty repair? BTW, I've
>>>> already reset the ECU once and this has only worked for a few days.
>>>>
>>>
>>> You do have the proper fuel cap, and it is done up the right amount
>>> of clicks? (if appropriate?)
>>>
>>> mrcheerful
>>>
>>>
>> Thanks for the reply, Mr C
>>
>> It's the original cap, AFAIK. I'll make sure it's tightened up fully.
>> The manual just says tighten until it clicks, doesn't mention a
>> specific number of clicks. AFAIK, the clicking is just a simple
>> clutch mechanism, to prevent overtightening, is it not? Are you
>> thinking that fuel is escaping via the filler cap (I feel that this
>> is unlikely), or is there some other significance?
>>
>> FTR, when the MIL came on for the first time, we had yet to refuel it
>> for the first time, so I don't think it's just something that just
>> SWMBO is doing wrong.
> 
> Lexus (Toyota in disguise) sometimes put  the light on if the cap is
> not tight, they recommend three clicks.  I imagine that it monitors
> tank pressure, which would disappear with a loose cap.
> 
> mrcheerful 
> 
> 

Thanks for the tip. I'll check the cap seal and tighten it. Then I'll 
reset the ECU again and see how it goes.



-- 
Stuart Sharp