Check Engine Lamp on '94 Camry V6 Goes On and Off

The check engine lamp on my '94 Camry V6 as come on and gone off twice
recently. I thought once a check engine lamp came on it stayed on
until something was done. Does anybody know what this on-off behavior
suggests?

-- jim

"jim evans" <jimsTAKEOUTnews2@houston.rr.com> wrote in message
news:92q452p8hk2c9vbu5jlpb2i807rtkcschq@4ax.com...[color=blue]
> The check engine lamp on my '94 Camry V6 as come on and gone off twice
> recently. I thought once a check engine lamp came on it stayed on
> until something was done. Does anybody know what this on-off behavior
> suggests?
>
> -- jim[/color]

If the check engine light is illuminated, it means that the electronic
control unit (ECU) has detected a problem. If the check engine light is
flashing, it means that the ECU has detected a serious problem and you need
to stop driving and/or take it to a dealer ASAP before serious damage is
done to the engine.

In some cases, there is 2-trip detection logic for the check engine light to
come on. In other words, a condition has to be present during 2 trip cycles
for the light to come on. If the problem is marginal or intermittent, the
ECU might not detect a problem and then turn off the light until it detects
the problem during 2 trips again. In this case, there is usually a trouble
code stored in the ECU.
--

Ray O
(correct punctuation to reply)

Ray, you should start a website called
"whattodoaboutyourOBDIIcheckenginelight.com"

"qslim" <Suckers@suckersdotcom> wrote in message
news:e00a2c4ba499180b7c8aa749ac44f351@localhost.talkaboutautos.com...[color=blue]
> Ray, you should start a website called
> "whattodoaboutyourOBDIIcheckenginelight.com"
>[/color]

LOL! Automakers should print it on the front cover of the owner's manual
too!

BTW, is a 94 Camry OBD II or previous generation?
--

Ray O
(correct punctuation to reply)

On Fri, 28 Apr 2006 14:59:43 -0500, "Ray O"
<rokigawa@tristarassociatesDOTcomn> wrote:
[color=blue]
>
>"jim evans" <jimsTAKEOUTnews2@houston.rr.com> wrote in message
>news:92q452p8hk2c9vbu5jlpb2i807rtkcschq@4ax.com...[color=green]
>> The check engine lamp on my '94 Camry V6 as come on and gone off twice
>> recently. I thought once a check engine lamp came on it stayed on
>> until something was done. Does anybody know what this on-off behavior
>> suggests?
>>
>> -- jim[/color]
>
>If the check engine light is illuminated, it means that the electronic
>control unit (ECU) has detected a problem. If the check engine light is
>flashing, it means that the ECU has detected a serious problem and you need
>to stop driving and/or take it to a dealer ASAP before serious damage is
>done to the engine.
>
>In some cases, there is 2-trip detection logic for the check engine light to
>come on. In other words, a condition has to be present during 2 trip cycles
>for the light to come on. If the problem is marginal or intermittent, the
>ECU might not detect a problem and then turn off the light until it detects
>the problem during 2 trips again. In this case, there is usually a trouble
>code stored in the ECU.[/color]

Thanks very much for your reply.

If I understand what you said the lamp coming on and then going out
indicates the problem happened on two successive trips, but did not
repeat on some later trip. So, the sequence goes like this:

The problem is detected.
The ignition key is turned off.
The car is started again.
The problem is detected again.
The lamp comes on.
The ignition key is turned off.
The lamp comes on every trip as long as the problem is detected. This
could be many trips.
There is a trip where the problem is not detected.
The ignition key is turned off.
The car is started again -- this time the lamp does not come on.

Then the cycle is repeated again the next time the problem is detected
twice in succession.

-- jim

"jim evans" <jimsTAKEOUTnews2@houston.rr.com> wrote in message
news:v6h552lttamo358hgl2qrikr5fvkkk2b77@4ax.com...[color=blue]
> On Fri, 28 Apr 2006 14:59:43 -0500, "Ray O"
> <rokigawa@tristarassociatesDOTcomn> wrote:
>[color=green]
>>
>>"jim evans" <jimsTAKEOUTnews2@houston.rr.com> wrote in message
>>news:92q452p8hk2c9vbu5jlpb2i807rtkcschq@4ax.com...[color=darkred]
>>> The check engine lamp on my '94 Camry V6 as come on and gone off twice
>>> recently. I thought once a check engine lamp came on it stayed on
>>> until something was done. Does anybody know what this on-off behavior
>>> suggests?
>>>
>>> -- jim[/color]
>>
>>If the check engine light is illuminated, it means that the electronic
>>control unit (ECU) has detected a problem. If the check engine light is
>>flashing, it means that the ECU has detected a serious problem and you
>>need
>>to stop driving and/or take it to a dealer ASAP before serious damage is
>>done to the engine.
>>
>>In some cases, there is 2-trip detection logic for the check engine light
>>to
>>come on. In other words, a condition has to be present during 2 trip
>>cycles
>>for the light to come on. If the problem is marginal or intermittent, the
>>ECU might not detect a problem and then turn off the light until it
>>detects
>>the problem during 2 trips again. In this case, there is usually a
>>trouble
>>code stored in the ECU.[/color]
>
> Thanks very much for your reply.
>
> If I understand what you said the lamp coming on and then going out
> indicates the problem happened on two successive trips, but did not
> repeat on some later trip. So, the sequence goes like this:
>
> The problem is detected.
> The ignition key is turned off.
> The car is started again.
> The problem is detected again.
> The lamp comes on.
> The ignition key is turned off.
> The lamp comes on every trip as long as the problem is detected. This
> could be many trips.
> There is a trip where the problem is not detected.
> The ignition key is turned off.
> The car is started again -- this time the lamp does not come on.
>
> Then the cycle is repeated again the next time the problem is detected
> twice in succession.
>
> -- jim[/color]

Basically, that's it, except that a "trip" is not necessarily just an on-off
of the ignition. There are parameters that define a trip, i.e., cold start
with coolant temp below a certain point, then engine and coolant warming up
to a different specified point, emissions system going into closed loop,
traveling a certain distance, etc.
--

Ray O
(correct punctuation to reply)

Some codes have a 1 trip detection logic also. At this time don't worry
about when it comes on but why did it come on... get the codes read and
report back to us.


--
Stephen W. Hansen
ASE Certified Master Automobile Technician
ASE Automobile Advanced Engine Performance
ASE Undercar Specialist

[url]http://autorepair.about.com/cs/troubleshooting/l/bl_obd_main.htm[/url]
[url]http://www.troublecodes.net/technical/[/url]
"jim evans" <jimsTAKEOUTnews2@houston.rr.com> wrote in message
news:v6h552lttamo358hgl2qrikr5fvkkk2b77@4ax.com...[color=blue]
> On Fri, 28 Apr 2006 14:59:43 -0500, "Ray O"
> <rokigawa@tristarassociatesDOTcomn> wrote:
>[color=green]
>>
>>"jim evans" <jimsTAKEOUTnews2@houston.rr.com> wrote in message
>>news:92q452p8hk2c9vbu5jlpb2i807rtkcschq@4ax.com...[color=darkred]
>>> The check engine lamp on my '94 Camry V6 as come on and gone off twice
>>> recently. I thought once a check engine lamp came on it stayed on
>>> until something was done. Does anybody know what this on-off behavior
>>> suggests?
>>>
>>> -- jim[/color]
>>
>>If the check engine light is illuminated, it means that the electronic
>>control unit (ECU) has detected a problem. If the check engine light is
>>flashing, it means that the ECU has detected a serious problem and you
>>need
>>to stop driving and/or take it to a dealer ASAP before serious damage is
>>done to the engine.
>>
>>In some cases, there is 2-trip detection logic for the check engine light
>>to
>>come on. In other words, a condition has to be present during 2 trip
>>cycles
>>for the light to come on. If the problem is marginal or intermittent, the
>>ECU might not detect a problem and then turn off the light until it
>>detects
>>the problem during 2 trips again. In this case, there is usually a
>>trouble
>>code stored in the ECU.[/color]
>
> Thanks very much for your reply.
>
> If I understand what you said the lamp coming on and then going out
> indicates the problem happened on two successive trips, but did not
> repeat on some later trip. So, the sequence goes like this:
>
> The problem is detected.
> The ignition key is turned off.
> The car is started again.
> The problem is detected again.
> The lamp comes on.
> The ignition key is turned off.
> The lamp comes on every trip as long as the problem is detected. This
> could be many trips.
> There is a trip where the problem is not detected.
> The ignition key is turned off.
> The car is started again -- this time the lamp does not come on.
>
> Then the cycle is repeated again the next time the problem is detected
> twice in succession.
>
> -- jim[/color]

You know, I can't remember for sure, but I want to say that the camry went
OBDII one year ahead, in '95. I would expect this guys camry to be the old
under-hood terminal jump deal, but I might be wrong.

On Fri, 28 Apr 2006 20:49:01 -0500, "Ray O"
<rokigawa@tristarassociatesDOTcomn> wrote:
[color=blue]
>BTW, is a 94 Camry OBD II or previous generation?[/color]

It's not the new universal type.

-- jim

"jim evans" <jimsTAKEOUTnews2@houston.rr.com> wrote in message
news:itq652ldf0co4b98k1psm6bo576o373avb@4ax.com...[color=blue]
> On Fri, 28 Apr 2006 20:49:01 -0500, "Ray O"
> <rokigawa@tristarassociatesDOTcomn> wrote:
>[color=green]
>>BTW, is a 94 Camry OBD II or previous generation?[/color]
>
> It's not the new universal type.
>
> -- jim[/color]

Let us know how it turns out.
--

Ray O
(correct punctuation to reply)

OK, the light came back and stayed so I had my favorite mechanic do
the code check. He specializes in Toyotas (Bob's Toyota), but isn't a
dealer mechanic. He said the light was pointing to an oxygen sensor,
and that he'd had a rash of Toyotas come in with this indication since
they began putting ethanol in the gasoline in our area. He thinks
ethanol is causing the oxygen sensor check engine warnings.



On Sat, 29 Apr 2006 04:03:21 GMT, "Stephen H" <hansensw@hotmail.com>
wrote:
[color=blue]
>Some codes have a 1 trip detection logic also. At this time don't worry
>about when it comes on but why did it come on... get the codes read and
>report back to us.
>
>
>--
>Stephen W. Hansen
>ASE Certified Master Automobile Technician
>ASE Automobile Advanced Engine Performance
>ASE Undercar Specialist
>
>[url]http://autorepair.about.com/cs/troubleshooting/l/bl_obd_main.htm[/url]
>[url]http://www.troublecodes.net/technical/[/url]
>"jim evans" <jimsTAKEOUTnews2@houston.rr.com> wrote in message
>news:v6h552lttamo358hgl2qrikr5fvkkk2b77@4ax.com...[color=green]
>> On Fri, 28 Apr 2006 14:59:43 -0500, "Ray O"
>> <rokigawa@tristarassociatesDOTcomn> wrote:
>>[color=darkred]
>>>
>>>"jim evans" <jimsTAKEOUTnews2@houston.rr.com> wrote in message
>>>news:92q452p8hk2c9vbu5jlpb2i807rtkcschq@4ax.com...
>>>> The check engine lamp on my '94 Camry V6 as come on and gone off twice
>>>> recently. I thought once a check engine lamp came on it stayed on
>>>> until something was done. Does anybody know what this on-off behavior
>>>> suggests?
>>>>
>>>> -- jim
>>>
>>>If the check engine light is illuminated, it means that the electronic
>>>control unit (ECU) has detected a problem. If the check engine light is
>>>flashing, it means that the ECU has detected a serious problem and you
>>>need
>>>to stop driving and/or take it to a dealer ASAP before serious damage is
>>>done to the engine.
>>>
>>>In some cases, there is 2-trip detection logic for the check engine light
>>>to
>>>come on. In other words, a condition has to be present during 2 trip
>>>cycles
>>>for the light to come on. If the problem is marginal or intermittent, the
>>>ECU might not detect a problem and then turn off the light until it
>>>detects
>>>the problem during 2 trips again. In this case, there is usually a
>>>trouble
>>>code stored in the ECU.[/color]
>>
>> Thanks very much for your reply.
>>
>> If I understand what you said the lamp coming on and then going out
>> indicates the problem happened on two successive trips, but did not
>> repeat on some later trip. So, the sequence goes like this:
>>
>> The problem is detected.
>> The ignition key is turned off.
>> The car is started again.
>> The problem is detected again.
>> The lamp comes on.
>> The ignition key is turned off.
>> The lamp comes on every trip as long as the problem is detected. This
>> could be many trips.
>> There is a trip where the problem is not detected.
>> The ignition key is turned off.
>> The car is started again -- this time the lamp does not come on.
>>
>> Then the cycle is repeated again the next time the problem is detected
>> twice in succession.
>>
>> -- jim[/color]
>[/color]


-- jim

Alas the poor O2 sensor, the most changed good part on the modern
automobile. A contaminated O2 sensor is most often the RESULT of some other
fault that is not allowing the microprocessor to control the fuel/air ratio
within it design parameters and activating the check engine light. If
anything the ethanol is probably just burning off some carbon deposits on a
twelve year old car. It could be as simple as a bad plug or wire. If not
look for a fuel metering or spark control problem, WBMA


mike hunt


"jim evans" <jimsTAKEOUTnews2@houston.rr.com> wrote in message
news:utsu62lohm75lt65vctlv9v1sfqbdnon60@4ax.com...[color=blue]
> OK, the light came back and stayed so I had my favorite mechanic do
> the code check. He specializes in Toyotas (Bob's Toyota), but isn't a
> dealer mechanic. He said the light was pointing to an oxygen sensor,
> and that he'd had a rash of Toyotas come in with this indication since
> they began putting ethanol in the gasoline in our area. He thinks
> ethanol is causing the oxygen sensor check engine warnings.
>
>
>
> On Sat, 29 Apr 2006 04:03:21 GMT, "Stephen H" <hansensw@hotmail.com>
> wrote:
>[color=green]
>>Some codes have a 1 trip detection logic also. At this time don't worry
>>about when it comes on but why did it come on... get the codes read and
>>report back to us.
>>
>>
>>--
>>Stephen W. Hansen
>>ASE Certified Master Automobile Technician
>>ASE Automobile Advanced Engine Performance
>>ASE Undercar Specialist
>>
>>[url]http://autorepair.about.com/cs/troubleshooting/l/bl_obd_main.htm[/url]
>>[url]http://www.troublecodes.net/technical/[/url]
>>"jim evans" <jimsTAKEOUTnews2@houston.rr.com> wrote in message
>>news:v6h552lttamo358hgl2qrikr5fvkkk2b77@4ax.com...[color=darkred]
>>> On Fri, 28 Apr 2006 14:59:43 -0500, "Ray O"
>>> <rokigawa@tristarassociatesDOTcomn> wrote:
>>>
>>>>
>>>>"jim evans" <jimsTAKEOUTnews2@houston.rr.com> wrote in message
>>>>news:92q452p8hk2c9vbu5jlpb2i807rtkcschq@4ax.com...
>>>>> The check engine lamp on my '94 Camry V6 as come on and gone off twice
>>>>> recently. I thought once a check engine lamp came on it stayed on
>>>>> until something was done. Does anybody know what this on-off behavior
>>>>> suggests?
>>>>>
>>>>> -- jim
>>>>
>>>>If the check engine light is illuminated, it means that the electronic
>>>>control unit (ECU) has detected a problem. If the check engine light is
>>>>flashing, it means that the ECU has detected a serious problem and you
>>>>need
>>>>to stop driving and/or take it to a dealer ASAP before serious damage is
>>>>done to the engine.
>>>>
>>>>In some cases, there is 2-trip detection logic for the check engine
>>>>light
>>>>to
>>>>come on. In other words, a condition has to be present during 2 trip
>>>>cycles
>>>>for the light to come on. If the problem is marginal or intermittent,
>>>>the
>>>>ECU might not detect a problem and then turn off the light until it
>>>>detects
>>>>the problem during 2 trips again. In this case, there is usually a
>>>>trouble
>>>>code stored in the ECU.
>>>
>>> Thanks very much for your reply.
>>>
>>> If I understand what you said the lamp coming on and then going out
>>> indicates the problem happened on two successive trips, but did not
>>> repeat on some later trip. So, the sequence goes like this:
>>>
>>> The problem is detected.
>>> The ignition key is turned off.
>>> The car is started again.
>>> The problem is detected again.
>>> The lamp comes on.
>>> The ignition key is turned off.
>>> The lamp comes on every trip as long as the problem is detected. This
>>> could be many trips.
>>> There is a trip where the problem is not detected.
>>> The ignition key is turned off.
>>> The car is started again -- this time the lamp does not come on.
>>>
>>> Then the cycle is repeated again the next time the problem is detected
>>> twice in succession.
>>>
>>> -- jim[/color]
>>[/color]
>
>
> -- jim[/color]