Code Help: P0138 and P144a at same time?

[bsgraham98]

Hello,

I recently purchased a 2015 PIU. After about a week of driving, the check engine light came on (not terribly surprised, that's what you get with used vehicles). I pulled the codes and got the following info:
P0138 (O2 sensor)
P144a (purge valve)
I was wondering if it was common for both of these codes to "blow" at the same time. I'm also experiencing some RPM flutter beginning around 1200 and a noticeable loss of power. Would either/both of these problems cause the RPM problem? I just bought a purge valve to replace the old one, but haven't installed it yet. I figured I'd start with the cheap and easy stuff first. I'm also going to take a look at the wiring harness when the weather is a bit better. I believe the 2 connectors for each part are near each other, so it could just be an electrical problem.

 

[peterk9]

Welcome to the Forum.
Which engine does your PIU have?

Peter

 

[bsgraham98]

Welcome to the Forum.
Which engine does your PIU have?

Peter

It has the 3.7l V6. I believe it has the flex fuel option, but I haven't tried E85 in it yet

 

[peterk9]

Thank you.

 

[bsgraham98]

Hello,

I recently purchased a 2015 PIU. After about a week of driving, the check engine light came on (not terribly surprised, that's what you get with used vehicles). I pulled the codes and got the following info:
P0138 (O2 sensor)
P144a (purge valve)
I was wondering if it was common for both of these codes to "blow" at the same time. I'm also experiencing some RPM flutter beginning around 1200 and a noticeable loss of power. Would either/both of these problems cause the RPM problem? I just bought a purge valve to replace the old one, but haven't installed it yet. I figured I'd start with the cheap and easy stuff first. I'm also going to take a look at the wiring harness when the weather is a bit better. I believe the 2 connectors for each part are near each other, so it could just be an electrical problem.

Update: I replaced the purge valve last night and cleared the codes. Still having the rpm flutter problem. Started her up to drive home from class, and as the rpms began to drop normally, they began jumping between 800 and 1100 for several seconds before going back down to normal idle at around 600. Checked my OBD logs when I got home and they reported that my PIU had gone through all of the drive cycle checks with no problems, including the O2 sensor.
I'm going to try the usual checks first: MAF sensor cleaning, air filter check, vacuum hose leaks, and resetting the PCM by disconnecting the battery.
This seems to be a common problem, but not too many of the threads are able to pin down an absolute cause.

 

[kerrybrod]

Yes the purge valve seems to be the common issue on these and a quick fix. The O2 sensor signals can cause the computer to make it flutter slightly. Let us know what else you find.

 

[peterk9]

Update: I replaced the purge valve last night and cleared the codes. Still having the rpm flutter problem. Started her up to drive home from class, and as the rpms began to drop normally, they began jumping between 800 and 1100 for several seconds before going back down to normal idle at around 600. Checked my OBD logs when I got home and they reported that my PIU had gone through all of the drive cycle checks with no problems, including the O2 sensor.
I'm going to try the usual checks first: MAF sensor cleaning, air filter check, vacuum hose leaks, and resetting the PCM by disconnecting the battery.
This seems to be a common problem, but not too many of the threads are able to pin down an absolute cause.

FYI, the 2016 retail units had throttle body issues.

Peter

 

[bsgraham98]

FYI, the 2016 retail units had throttle body issues.

Peter

Update:
Cleaned the throttle body
Cleaned the MAF sensor
Disconnected the negative battery terminal for a while to reset PCM
Filled up gas tank with premium no ethanol gas and seafoam

I still have the fluttery throttle problem. I'm thinking I'll replace the throttle body first because it's cheaper and lower risk than getting a transmission flush. Thoughts?

 

[gapcomputer]

check your vehicle for recalls i had 2 recalls and 2 field service actions on mine, i know canister purge valves was one of them https://owner.ford.com/tools/account/maintenance/recalls.html

 

['14FPIU]

Update:
Cleaned the throttle body
Cleaned the MAF sensor
Disconnected the negative battery terminal for a while to reset PCM
Filled up gas tank with premium no ethanol gas and seafoam

I still have the fluttery throttle problem. I'm thinking I'll replace the throttle body first because it's cheaper and lower risk than getting a transmission flush. Thoughts?

As unrelated as it sounds, try changing your transmission fluid. This has been a common solution to RPM fluttering in the past where departments haven't changed the transmission fluid.

 

[bsgraham98]

Update: I noticed that having a full tank of 89 or 91 octane (med or premium grade) fuel helps. I've not tried E-85 because I've heard it can make the engine run worse over time. I'm inclined to believe it could be a spark or fuel problem despite no misfire codes.
I have some spark plugs and a PCV valve on the way to install. My PIU is at 130k miles, so I figured I'm due for plug changes anyway, and I might as well replace the PCV valve while I have the intake off. I'm currently tracking down a reputable shop to do a transmission flush. I live right next to a Ford dealership, so I'll probably go there and pay the extra for the convenience and having it done "right".

 

['14FPIU]

Update: I noticed that having a full tank of 89 or 91 octane (med or premium grade) fuel helps. I've not tried E-85 because I've heard it can make the engine run worse over time. I'm inclined to believe it could be a spark or fuel problem despite no misfire codes.
I have some spark plugs and a PCV valve on the way to install. My PIU is at 130k miles, so I figured I'm due for plug changes anyway, and I might as well replace the PCV valve while I have the intake off. I'm currently tracking down a reputable shop to do a transmission flush. I live right next to a Ford dealership, so I'll probably go there and pay the extra for the convenience and having it done "right".

I've heard horror stories about getting the transmission fluid flushed and the transmission needing to be replaced after. Just do a few drain and fills yourself. There's a super easy drain plug to get to under the FPIU that you don't even need to jack the car up to access.

 

[bsgraham98]

I've heard horror stories about getting the transmission fluid flushed and the transmission needing to be replaced after. Just do a few drain and fills yourself. There's a super easy drain plug to get to under the FPIU that you don't even need to jack the car up to access.

Update: should have gone with the transmission drain/fill first! I did a total of 3, each replacing about 4.5 to 5 quarts. Ran better after the first one and has gotten better with each subsequent drain/fill. The bright side to all of the parts I initially replaced to resolve the issue is that they were likely worn anyway (I'm at 130k miles), so I essentially got a basic tune-up out of the ordeal. Thank you all for your advice!