Hi all,

I recently traded my '97 Ford F150 extended cab 4X4 for a '02 Ford F150 short box crew cab 4X4. Both have 4.6 Triton engines.

After driving the 2002 for awhile the "Service Engine Soon" light comes on and stays on, no flashing. Any ideas why it might be on? It has 83,000 (highway) miles on it, is an ex fleet truck driven by a good driver and it has a very good service history. I was told years ago these lights come on after XXX miles. Is this still true? I mean, when they run rough or something I know there's something wrong but this puppy runs like a champ... even with the light on. I quit serious wrenching years ago and am confounded by these new gadgets.

Also, the '97 Triton engine was a puker (my personal opinion) but I was told the 2002 is much improved over the '97. Is this true? If not (or even if so) what should I be looking for re: maintenance and all. The '97 blew a head gasket at 62,000 miles but the light flashed... normally, and in the past replacing the head gaskets was a relatively simple repair. Not with that particular truck! I won't go into detail but it wasn't pretty nor cheap! Should I buy a code reader or is there a place that'll read the code for less than $80.00 like Autozone, NAPA or Cut Rate?

 

With the miles on your truck, and you said it ran good, i would look for an EGR problem. Most likely a low flow prob. It could be the DPFE Sensor, or a pluged up passage in the throttle body. Have the codes read by AutoZone or someone, then let us know before you spend money on lot of parts. We might be able to save you a little.

 

I agree with Bosshoss. With that many miles low ERG flow is a common problem. Take it to Autozone and have them read the codes. They will do it for free and then post the codes, maybe then we can help. There are many codes but I understand code P0401 is common at that milage.There are several reasons this code can appear. I just fixed my 98 F150 4.6 L 112,000 Miles with the P0401 code. It turned out to be the EGR Ports were clogged with carbon. Disconnect the vacuum hose front the ERG and cap it. Then apply vacuum (outside source) to the ERG while the engine is idling. If it continues to run smoothly the ports are blocked. The engine should stumble or stall if the ports are clear. To clean them you will have to remove the throat from the manifold. The EGR Valve or the PDFE Switch could also be the problem.

You have less mileage than I did but it could still be carbon buildup and the test is easy so give it a try and Good Luck

 

Take it to AutoZone, they will check it for free. Let us know what the code is.

 

Mine came on last week. ran great, took it to dealer and they put in new thermostat, said it ran to cold for proper emissions. N/C

 

bosshoss, where does one get the outside vacuum from? I understand to cap the original vacuum line to the EGR but I wouldn't know where to gather another line from. Thanks in advance.

I am having the P0401 code as well in my '99 F250 SD, with 125,000+ miles.

EDIT: oops, I meant 50th ann. Sorry

 

Hey 351cobra.
I like that name. Thats what i put in my 73Mach1. Now for a vacume source. see if AutoZone will loan you a vacume tester hand pump. Remove the line from the EGR Valve and hook the tester to it. with the engine worm and idleing apply vacume to the EGR. The motor should just about stall or stumble. If it does this, your EGR should be ok. I would look at the DPFE Sensor next. At idle and no vacume on the EGR Valve i think you should have about .5 to1.0 volts comeing from the DPFE. As you add more vacume the voltage should increase to about 4.75 volts i think. If the ports in the intake are pluged up, or almost pluged up you wont get the feedback voltage like you should and then the dreaded low flow. If the ports are open, then i would change the DPFE. I would pull the elbow off the intake and clean the ports anyway. Have to Run good luck, talk to you later