I just bought a used 1997 F-150 with 152,000 miles. When I bought the truck, the check engine light was on, so I took it to AutoZone this morning to get the codes read. Two codes came up - one saying excessive EGR flow, another saying insufficient EGR flow.

When I started the truck up to leave, the Check Engine light was off. Drove a few miles home, still off.

Does reading the codes reset the light?

Also, what kind of problems could cause what seems to be contradictory codes to show up?

Any help would be appreciated! Thanks!

 

I took my egr junk off and it doesnt affect anything...

 

On mine it was the egr sensor. Found out after I replaced the valve. It was like 20.00 bucks at advanced.

 

There isn't any such thing - EGR sensor ? There's just the valve , EVR, DPFE....

 

Sounds like AZ cleared the code. They are not supposed to do that. You could be having problems with the hoses to the DPFE, one being blocked/clogged, one of the hoses off, or most common the DPFE itself.

 

No they reset the light , ther not suppose to. They may ask if you if you want them to rest it , but what they did was wrong..

Usually it's the DPFE that goes bad - instead of the EGR valve -

 

torkum , you frickin beat me to it lol

 

Great minds run together. I see you got the nice drawings

 

yeah that' an old ALLDATA one that's been around forever..

 

AZ told me to drive for 10 to 15 miles and if the light comes back on, come by to read again. Is there any harm in doing that? I don't want to cause unnecessary damage to the truck.

 

No , no harm - you don't even need an EGR system , that was already said..

But it's usually the DPFE that gets buggy..

 

Just replace the DPFE sensor then reset your PCM.

..and buy if from Ford, not AutoZone....

Steve

 

Howcome you bought the truck with the CEL on? Did the previous owner tell you about it first?

 

His widow sure did tell me about it. And based on the research I did online, I figured it wasn't a big deal.

After going to AZ today, I just had questions about the reason the light was:
A) off, and
B) yielding contradictory codes.

I was well aware of the situation, and paid accordingly for the truck. Just wanted to get some feedback off the forum for the error code.

 

Thanks Steve - should I be waiting for the check engine light to come back on??

Hasn't yet today - put at least 20 miles on it...