Flashing Check Engine Light... but no codes??
Thread Starter
Race Director
Joined: Feb 2002
Posts: 16,105
Likes: 7
From: Canal Winchester OH
CI 3-4-5-6-7-8-9-10-11 Vet
CI X Blind Auto-X Champ
Flashing Check Engine Light... but no codes??
New C5 owner here 
I have a 2001 Convertible that has had a cam, heads, and headers put on by the previous owner. Car runs GREAT, however it does give me the flashing Check Engine light at times. It does not throw any engine codes. It seems to come on usually when at a steady speed in either 5th or 6th gear, especially when going up a slight incline. There is NO power loss, doesn't seem to run rough, or any other indication that there is a problem. I took it to a tuner last weekend to have the tune checked and he found nothing wrong. We had the computer hooked up while driving and the Check Engine light did start flashing. He ran tests and NOTHING showed up. He checked for Misfires and the computer showed nothing. Everything appeared good to him.
What other conditions could exist that could be causing the computer to do this? What other things could be checked to narrow down the problem? I am not mechanically inclined so any help would be appreciated
Thanks!!
I have a 2001 Convertible that has had a cam, heads, and headers put on by the previous owner. Car runs GREAT, however it does give me the flashing Check Engine light at times. It does not throw any engine codes. It seems to come on usually when at a steady speed in either 5th or 6th gear, especially when going up a slight incline. There is NO power loss, doesn't seem to run rough, or any other indication that there is a problem. I took it to a tuner last weekend to have the tune checked and he found nothing wrong. We had the computer hooked up while driving and the Check Engine light did start flashing. He ran tests and NOTHING showed up. He checked for Misfires and the computer showed nothing. Everything appeared good to him.What other conditions could exist that could be causing the computer to do this? What other things could be checked to narrow down the problem? I am not mechanically inclined so any help would be appreciated
Thanks!!
Race Director
Joined: Oct 2002
Posts: 16,477
Likes: 26
From: Gone
CI 6-7-8-9-10 Veteran
St. Jude Donor '03
Have your tuner check if P0300 is set to "Not report" in your current tune. It will do exactly what you are describing.
My cammed car used to set off the false misfire (and flashing CE light) at idle due to the loping. I initially turned P0300 off and set to no MIL, but the flashing engine light continued, just w/o the code displaying. I bet whoever tuned your car did this.
So, if you re-enable the code, it will still flash the light, only difference you'll see is that P0300 is reported along with it. Doesn't really fix the issue of why the misfire is being detected when the car is running smoothly. If it were strictly an idle thing due to the cam lope, I'd tell ya how to fix it, but that doesn't seem to be your issue.
My cammed car used to set off the false misfire (and flashing CE light) at idle due to the loping. I initially turned P0300 off and set to no MIL, but the flashing engine light continued, just w/o the code displaying. I bet whoever tuned your car did this.
So, if you re-enable the code, it will still flash the light, only difference you'll see is that P0300 is reported along with it. Doesn't really fix the issue of why the misfire is being detected when the car is running smoothly. If it were strictly an idle thing due to the cam lope, I'd tell ya how to fix it, but that doesn't seem to be your issue.
Thread Starter
Race Director
Joined: Feb 2002
Posts: 16,105
Likes: 7
From: Canal Winchester OH
CI 3-4-5-6-7-8-9-10-11 Vet
CI X Blind Auto-X Champ
Have your tuner check if P0300 is set to "Not report" in your current tune. It will do exactly what you are describing.
My cammed car used to set off the false misfire (and flashing CE light) at idle due to the loping. I initially turned P0300 off and set to no MIL, but the flashing engine light continued, just w/o the code displaying. I bet whoever tuned your car did this.
So, if you re-enable the code, it will still flash the light, only difference you'll see is that P0300 is reported along with it. Doesn't really fix the issue of why the misfire is being detected when the car is running smoothly. If it were strictly an idle thing due to the cam lope, I'd tell ya how to fix it, but that doesn't seem to be your issue.
My cammed car used to set off the false misfire (and flashing CE light) at idle due to the loping. I initially turned P0300 off and set to no MIL, but the flashing engine light continued, just w/o the code displaying. I bet whoever tuned your car did this.
So, if you re-enable the code, it will still flash the light, only difference you'll see is that P0300 is reported along with it. Doesn't really fix the issue of why the misfire is being detected when the car is running smoothly. If it were strictly an idle thing due to the cam lope, I'd tell ya how to fix it, but that doesn't seem to be your issue.
Thread Starter
Race Director
Joined: Feb 2002
Posts: 16,105
Likes: 7
From: Canal Winchester OH
CI 3-4-5-6-7-8-9-10-11 Vet
CI X Blind Auto-X Champ
Thread Starter
Race Director
Joined: Feb 2002
Posts: 16,105
Likes: 7
From: Canal Winchester OH
CI 3-4-5-6-7-8-9-10-11 Vet
CI X Blind Auto-X Champ
Thanks everyone for the suggestions
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