Jerking when accelerating- P051B Crank case Pressure?m sensor?

[cliftonlawson]

Hey everyone! I’m brand new! I have a 2017 Ford expedition, and have been experiencing an issue when accelerating. There is some jerking, and if you try to push beyond the jerking the check engine light flashes briefly.

We had this issue before, and the spark plugs were replaced, as well as an O2 sensor I believe. I’m being told that the only error popping up now is a P051B - a crankcase pressure sensor. The replacement will run 329 bucks.

I’m fully prepared to get it replaced, but just wondering if others have experienced a similar issue with that being the fix. Thanks!!

 

[99WhiteC5Coupe]

Hey everyone! I’m brand new! I have a 2017 Ford expedition, and have been experiencing an issue when accelerating. There is some jerking, and if you try to push beyond the jerking the check engine light flashes briefly.

We had this issue before, and the spark plugs were replaced, as well as an O2 sensor I believe. I’m being told that the only error popping up now is a P051B - a crankcase pressure sensor. The replacement will run 329 bucks.

I’m fully prepared to get it replaced, but just wondering if others have experienced a similar issue with that being the fix. Thanks!!

The crankcase pressure sensor tube is Ford part number FL3Z-6758-A (which fits the 2015 - 2017 Expedtion).

I changed the part on my 2015 Expedition Limited 4x4, purchased new. The original part number on the original part was FL3E-6758-CC.

The part is about $40 at some online Ford part’s dealers.

It takes about 3-5 minutes to change the part, taking your time. I changed mine.

You are being overcharged unless the $329 includes other items and expenses.

Here is a post with a photo of the part: https://www.expeditionforum.com/threads/2017-crankcase-pressure-sensor-location-p051b-code.50338/

I also changed the PCV valve, which is on the right (passenger) side valve cover. It also takes about 3-5 minutes to change. It is inexpensive and I used a Motorcraft part (not aftermarket).

 

[cliftonlawson]

Thank you so much! I’m definitely willing to try fixing it myself. I’m just concerned that it’s actually not the real problem for the jerking when accelerating.

 

[99WhiteC5Coupe]

Thank you so much! I’m definitely willing to try fixing it myself. I’m just concerned that it’s actually not the real problem for the jerking when accelerating.

If you need instruction on how to replace the pressure sensor tube or the PCV valve, just ask.

Good luck.

 

[cliftonlawson]

Hey! Yes any instruction you may have would be great!

 

[99WhiteC5Coupe]

Hey! Yes any instruction you may have would be great!

The crankcase pressure sensor tube has one electrical connector in the middle and two quick-disconnect fittings, one at each end. It is on the left (driver) side of the engine, on top. If you have the new part - the old part should be obvious.

Remove the sound insulator cover from the engine. Locate the sensor. Push the gray tab on each disconnect to the left, and pull the tube off of the fitting. Remove the electrical connect (in the middle of the tube). The sensor tube in installed in the reverse of its removal.

The sensor will only fit one way. Take note of its orientation before removing the old one (take a cell phone photo).

The PCV valve is on the right (passenger side) of the engine valve cover - slightly toward the rear from the middle of the cover. Remove the quick disconnect fitting, then twist the valve counter clockwise out of its bushing. If I recall correctly, the valve has a square base - which makes it easy to use a channel-lock pliers or large adjustable wrench to remove it. It is threaded and simply screws-in to the bushing (unlike older PCV valves which push-in the valve cover bushing). I always recommend OEM Motorcraft parts (instead of aftermarket) - as the PCV was inexpensive.

Reinstall the sound cover.

Good luck.

 

[cliftonlawson]

Thank you so much! I was able to replace both parts today. Unfortunately, it’s still doing some jerking when accelerating. I got a scan at O’Reilly auto parts, and nothing came up. Perhaps carbon buildup? Any recommended next steps that I can take on my own?

 

[99WhiteC5Coupe]

Thank you so much! I was able to replace both parts today. Unfortunately, it’s still doing some jerking when accelerating. I got a scan at O’Reilly auto parts, and nothing came up. Perhaps carbon buildup? Any recommended next steps that I can take on my own?

My 2015 Expedition Limited 4x4 began jerking while lightly accelerating on a level roadway, or uphill. It felt as though I was driving on a roadway rumble strip. The jerking was intermittent.

Long story short - the transmission failed, with the torque converter being one of the failed components.

There were no stored trouble codes (no check-engine light), but numerous stored transmission trouble codes retrieved by the Ford dealer.

 

[Calman2k]

Thank you so much! I was able to replace both parts today. Unfortunately, it’s still doing some jerking when accelerating. I got a scan at O’Reilly auto parts, and nothing came up. Perhaps carbon buildup? Any recommended next steps that I can take on my own?

Ooo, I know this one. I have a 16 and had this same issue, just solved it last month. It is the plugs. The computer will allow the lower compression for quite a while before throwing a code. And after load on the engine goes down (reducing rpm and engine load) the dummy light will actually go out. I went through 4 sets of plugs in less than 15k miles. Turned out the problem was the boots on the end of the coil packs. They get hard and stop insulating the plug and it causes the ceramic to crack. I got new coil packs and a last set of plugs and the problem never came back.

 

[cliftonlawson]

The plugs were replaced last year… I just put some CRC through the intake valve, and I’m going to get an oil change… So I guess I’ll see what that does if anything.

 

[Calman2k]

The plugs were replaced last year… I just put some CRC through the intake valve, and I’m going to get an oil change… So I guess I’ll see what that does if anything.

My first set of new plugs blew after just a few hundred miles, right after they had been replaced in the 100k service. I had them done and went on a road trip from TN to KS for a business thing, on the way home the one on cylinder 3 let go and I had to limp it home by keeping the compression pressures as low as possible, light presses on the pedal and no hard acceleration. It ate 2 more sets of plugs shortly after that. Replacing the coils is what fixed it. I think the rubber boot gets hard and when the plugs get replaced the rubber can't re-form around the plug properly.

 

[Motorcity muscle]

May want to get the truck scanned by a shop, they have better scanners that show more details then auto parts. Had same problem, thinking it was trans, it was the plugs and boots.