1999 Ranger with EGR code P0401

Have a Ranger 3.0L with check engine light on. Code initially said insufficent egr flow. Replaced the EGR valve, the DPFE sensor, and the EGR flow regulator but still the light remains. Engine runs a little sluggish but no spark knock. Last trip to mechanic he said the code needed reset. 30 minutes later light back on. Ready to put black tape over cluster! Help!

Both sides of the EGR valve need to be free flowing. That means from where tube hooks up to exhuast, thru EGR valve and into intake. Lots of carbon buildup between EGR valve and intake side very common.

Stay cool.

Both sides of the EGR valve need to be free flowing. That means from where tube hooks up to exhuast, thru EGR valve and into intake. Lots of carbon buildup between EGR valve and intake side very common.

Stay cool.
Hey thanks for the feedback! Tell me, the EGR attachs directly to the intake and that cavity is quite large (didn't see much carbon build up there with the valve off). Are you saying the 15" long pipe connected to the bottom of the EGR going down to the exhaust should be removed and cleaned? They did tell me when I bought the EGR to clean something they (Autozone) just didn't know what. Thanks again. These CEL drive me nuts!

The intake manifold is the side that seems to plug the most. I would just take off the EGR valve, try to blow air into intake. Then blow into the tube that goes to exhaust. Most likely the tube isn't plugged but make sure. I cant' remember the exact route or cavities of your system. Just make sure clear path from exhaust to intake, through intake and into cylinders.

Stay cool.

The intake manifold is the side that seems to plug the most. I would just take off the EGR valve, try to blow air into intake. Then blow into the tube that goes to exhaust. Most likely the tube isn't plugged but make sure. I cant' remember the exact route or cavities of your system. Just make sure clear path from exhaust to intake, through intake and into cylinders.

Stay cool.
Thanks again! The intake is a monster and the EGR attach opening is pointing toward the front of the intake. After blowing air in what would you recommend to clean with if I sense a blockage? Can I spray carb cleaner in? Sorry to question you to death.

I work on so many different systems it hard to remember each one specifically. You would only pull upper intake. Also there is a transducer in there somewhere that measures exhaust flowing past the EGR. I think the best I can say is all passages need to be clear and clean. No cleaner will eat that carbon out. You have to scrape and chisel.
Good luck!

I work on so many different systems it hard to remember each one specifically. You would only pull upper intake. Also there is a transducer in there somewhere that measures exhaust flowing past the EGR. I think the best I can say is all passages need to be clear and clean. No cleaner will eat that carbon out. You have to scrape and chisel.
Good luck!
Removed the EGR and the throttle body to confirm that the passage between the valve opening and the main intake cavity was clear. Went on to the lower half. Was unable to remove the lock nut as it was frozen to the pipe but did blow air into the Egr side. Started it up and blew out alot of air. Didn't seem to be blocked there. Still light persists. I believe the transducer you mention is the DPFE (differential pressure flow). Did that one too. I guess I'll ned to pony up to the dealer soon. I appreciate your help. You gave me some hope that I would find this thing without dumping a bundle into it.

Your trouble code indicates an IAT sensor Circuit, you mentioned in one of your threads that the light went out and then relit. Try disconnecting your negative battery terminal for 5 minutes. Replace your negative lead and drive the vehicle for about 10 minutes, it will probably run rough but that is the computer resetting itself. Don't know for sure if this will work but it's worth a try
Gordie :screwy:

Hello to all.

I have the same problem as mentioned in this thread. It is a 99 3.0L Ranger. I get code P0401, insufficient EGR flow. I took out the EGR valve and made sure both ends looked clean. They did. The intake manifold seemed clean also.

I did not want to go relplacing everything for no reason.

Splolando, I was wondering if you ever got your problem fixed. If so, what was the final fix.

Does anyone else have any suggestions on how to determine which component is not working.

One last thing, after reconnecting the batter terminal the CEL was off for about 15 miles and then it came back on.

The vehicle does have some spark knock but it has for a long time.

Hello to all.

I have the same problem as mentioned in this thread. It is a 99 3.0L Ranger. I get code P0401, insufficient EGR flow. I took out the EGR valve and made sure both ends looked clean. They did. The intake manifold seemed clean also.

I did not want to go relplacing everything for no reason.

Splolando, I was wondering if you ever got your problem fixed. If so, what was the final fix.

Does anyone else have any suggestions on how to determine which component is not working.

One last thing, after reconnecting the batter terminal the CEL was off for about 15 miles and then it came back on.

The vehicle does have some spark knock but it has for a long time.

Mcapper, I finally ran into a mechanic that works for Ford and does side jobs. Here's how he fixed my truck: 1). He said that Ford had a new version of the DPFE that I had to get from them. After replacing the one I bought from Autozone (and correcting a leaking EGR gasket), my problem was solved. My truck runs much better now as the right air mixture is being monitored with the DPFE. If you have a 3.0L, you may notice like I did that the performance was poor.
Good luck.
Spolando

Well, I finally fixed it. It turned out to be the DPFE sensor.

FYI for future readings. In my case if I measured resistance from the Vref pin and the DPFEVGR pin on the sensore I got very little resistance. about .5ohms. On the new sensor, checking the same points I got 'OL'--it was open. I am no expert but it seems that my old sensor was shorted to ground. I think it is worth checking if you think your DPFE sensor is going bad.

Problems: I have a check engine light on. I went to Auto Zone and they pulled the codes off. The codes were P0151- O2 Sensor Circuit Low Voltage (Bank 2 Sensor 1), P0174- System too Lean (Bank 2), and P0153- O2 Sensor Circuit Slow Response (Bank 2 Sensor 1). The check engine light usually stays on for a few days and then goes off for a few days. The truck seems to run fine. Any input you can give will be appreciated.

for code P0151, ford manual says:

Contaminated HO2S/Voltage Shift
P0151=HO2S-21
Check for water in HO2S connector.

If there is water, fix it. If not:
Measure resistance from HO2S singal circuit and HO2S signal return between PCM harness connector pin and HO2S connector pin. If resistance is less than 5ohms replace HO2S. Otherwise repair as necassary.

P0174: Check intake air system for obstuctions, verify intergrity of PCV, and check for vaccuum leaks.