Check Engine Light - PO401????

OK guys . . . my check engine light came on this morning. Went to Checker Auto and they pulled the following code/description:

PO401 - "Exhaust Gas Recirculation Flow Insufficient Detected"

Any thoughts as to what this is?

Your EGR and EGR tube are plugged up. Read up in the FAQs on how to clean it.

Your EGR and EGR tube are plugged up. Read up in the FAQs on how to clean it.

Thanks, Ryan . . . I've give it a look. I'm heading up to our cabin tonight for the weekend (fortunately we can take our other SUV). Hopefully I can try to clean it out on Sunday.

Is this something that is "harmful" or is it more something that will just affect performance/emissions a little until I can clean it?

Update . . . looks like cleaning the EGR may have done the trick. I just cleaned it out and disconnected the battery for a few minutes. No more Check Engine Light! I'll just keep an eye on it and see how it goes.

This was a really easy DIY thing to do. I am embarrassingly non-mechanically-inclined, but this was a breeze using the instructions from the FAQ.

I have to say that this forum is just fantastic . . . this could easily have run me a couple hundred bucks at a repair shop to get diagnosed and fixed. But thanks to this site, I knew to go to an auto parts store to get the code identified (FREE) and then all it took was 15 minutes and a $3 can of intake cleaner. So if this was the solution for the issue, then what a bargain to fix it.

let us no how it goes im not convinced the ck eng light will remain off

let us no how it goes im not convinced the ck eng light will remain off

I will definitely post an update if it comes back on. I'm cautiously optimistic that this fixed the issue.

Any thoughts on other potential causes . . . just so I can be prepared for "round 2"?

I will definitely post an update if it comes back on. I'm cautiously optimistic that this fixed the issue.

Any thoughts on other potential causes . . . just so I can be prepared for "round 2"?

I cleaned mine a couple of weeks ago and the CEL went off, but now it comes on and turns off every now and then... I used carb cleaner safe of O2 sensors, but I didn't use that much of it. I am going to clean it up again soon and just use most of the can this time.

Well . . . it's back. Check Engine light has been going on/off intermittently over the last week or so. Yesterday it came on in the morning, so I stopped at Checker Auto Parts and they read the code--same PO401.

I went ahead and cleaned the EGR port again after that. The first time I did it, I did not use the full can of intake cleaner (I only used about 1/2). So I used a whole can this time around, disconnected the battery to clear the code, and we'll see how it goes. Are there other causes for this error, or is EGR pretty much it?

make, year, model,& miles would help

make, year, model,& miles would help

'98 Passport EX, 140k.

The first time the EGR ever got cleaned out was last month when I first posted . . . so maybe there is just so much crap built up that it will take more than one cleaning to get the error to stop showing up?

I have cleaned the EGR port 4 times,replaced EGR valve twice,replaced MAP sensor and still have the check engine light (p0401) come on at times. I have all but given up trying to fix unless someone else has any ideas?

Is that the same code for a loose or leaking gas cap?

I too struggled with this for a while. The key for mine (2000) was to not focus on the EGR valve itself, but to remove the intake manifold and get into the throttle body where sure enough, the EGR pipe was clogged at the tip. A high-pressure can of carb cleaner and a straightened wire hanger later, the carbon broke off and cleared the tube.

Next time, I am going to get a test-tube brush to really get in there. For two months, mileage has increased and no MIL mean I did a great job!

-Douglas

Is that the same code for a loose or leaking gas cap?

No, gas cap is usually P0440.

Thanks, guys . . . I'll just keep an eye on it and see what happens. I'm not very mechanically inclined, unfortunately (not when it comes to cars anyway), so not sure I would even know what to do in order to remove the exhaust manifold and clean around in there. I'd probably screw it up worse. :biggrin:

There are actually several possible causes for a P0401 (it's P zero four zero one, BTW) a clogged EGR tube is only one. Your EGR valve could be bad. The EGR control solenoid could be bad (if there is one). The EGR flow sensor could be bad (the component that actually senses EGR flow). Or any of the wiring involved with these components could be bad. I'm assuming that this year Rodeo has a linear electronic EGR valve and is not vacuum operated. If it is vacuum operated, you will want to check the condition of all vacuum lines leading up to the EGR valve including the EGR transducer. Simply follow the EGR valve vacuum line back and you'll find the transducer and then keep following it as you carefully inspect the lines and connections along the way.

Probably a stupid question but did you have the guy at Checker clear the code? It'll stay in your ECM until you do...

GOOD POINT BUT....engine lamp would not light up unless there is a problem