Check engine light problem? -
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post #1 of 7 Old 07-25-2012, 09:17 PM Thread Starter
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Check engine light problem?

Ive had my check engine light on for quite some time now. My assumption was why it was on was some creep apparently tried to steal one of catalytic converters. (Theres a cut from a sawzall (assuming) half way through the exaust so therefore it leaks. I put exaust pipe tape around the leak for a temporay fix so i can clear the code and pass inspection. I cleared the code
Disconecting the battery for approx 30 seconds. The check engine light went away when i started the jeep but what i noticed and my question is (finally) when the ignition key is on but the jeep is NOT running the check engine light will flash.... Is this bad or is the computer just doing a check on itself. Never came across this before thanks for any input

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post #2 of 7 Old 07-26-2012, 07:01 AM
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Its only a problem if the light is on with the engine running. The system checks itself everytime you start it.

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post #3 of 7 Old 07-26-2012, 11:18 AM
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you need to disconnect the batt for at least 5 min. if the check engine light flashes while the engine is running, means it is something serious.
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post #4 of 7 Old 07-26-2012, 02:55 PM
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If I'm understanding you correctly OP, mine does the same thing. When I first turn the key to "ON" without the engine running the CEL will come on solid for a few seconds and then I will hear the *ding* and it will start flashing. When I start the engine it disappears altogether and there is no code.

As long as it isn't flashing when the engine is running you are fine. If it is flashing with the engine running it is a SERIOUS issue as noted above and the Jeep should be stopped immediately and towed.
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post #5 of 7 Old 07-26-2012, 03:07 PM
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Flashing before starting is clearly an indicator of some sort as it is NOT normal. I'm not sure what it means, but I don't think I would give up until I figured it out
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post #6 of 7 Old 07-26-2012, 03:40 PM
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This information is in your owners manual .
For states which have an I/M (Inspection and
Maintenance) requirement, this check verifies the
following: the MIL (Malfunction Indicator Lamp)
is functioning and is not on when the engine is running,
and that the OBD (On Board Diagnostic) system is ready
for testing.
Normally, the OBD system will be ready. The OBD
system may not be ready if your vehicle was recently
serviced, if you recently had a dead battery, or a battery
If the OBD system should be determined
not ready for the I/M test, your vehicle may fail the test.
Your vehicle has a simple ignition key actuated test
which you can use prior to going to the test station. To
check if your vehicle’s OBD system is ready, you must do
the following:
1. Insert your ignition key into the ignition switch.
2. Turn the ignition to the ON position, but do not crank
or start the engine.
3. If you crank or start the engine, you will have to start
this test over.
4. As soon as you turn your key to the ON position, you
will see your MIL symbol come on as part of a normal
bulb check.
5. Approximately 15 seconds later, one of two things will
a. The MIL will flash for about 10 seconds and then
return to being fully illuminated until you turn off the
ignition key or start the engine. This means that your
vehicle’s OBD system is not ready and you should not
proceed to the I/M station.
b. The MIL will not flash at all and will remain fully
illuminated until you turn off the ignition key or start
the engine. This means that your vehicle’s OBD system
is ready and you can proceed to the I/M station.
If your OBD system is not ready, you should see your
authorized dealer or repair facility. If your vehicle was
recently serviced or had a battery failure or replacement,
you may need to do nothing more than drive your
vehicle as you normally would in order for your OBD
system to update.
A recheck with the above test routine
may then indicate that the system is now ready.
Regardless of whether your vehicle’s OBD system is
ready or not ready, if the MIL symbol is illuminated
during normal vehicle operation, you should have your
vehicle serviced before going to the I/M station. The I/M
station can fail your vehicle because the MIL symbol is on
with the engine running.

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post #7 of 7 Old 07-26-2012, 04:11 PM
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Ahh.. You know what they say about assuming...

I just realized that every time I observed it flashing was after I cleared a code. Just went out and tried it and it stays on solid. So, OP, there's your answer. Just drive it normally for a few days and check it again to see if OBD is "ready".

I've never lived in a county that required vehicle inspections so I've never needed to check to see if the system was ready.
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