Hey there,

I'm kinda a new Chrysler owner and not so excited by the way this Pacifica has stumped me. I have a 2018 Chrysler Pacifica Limited and I've had some trouble locating a fix to the above codes.

Here is what I've done. I had a misfire and fixed that by changing plugs and coils (Car has 132K Miles). Additionally, I decided to change out the injectors as I figured a tuneup while the plenum was off would be a good thing.

After changing that I got the P0175, and P0172 code that has driven me almost crazy. I figured that it would be an Oxygen sensor fix...so I went down and grabbed four Bosch sensors and still have the code. While that was going on I got a MAP sensor issue...so I changed the MAP and that code left. My Short Term Fuel Trim is at -33.6% and Long Term Fuel Trim is at -32.6%.

Any ideas as to how to fix this code?

 

Those fuel trims run the risk of overheating (think fire hazard) and possibly destroying the catalytic converter.

What is are the fuel trim numbers for bank 1 (cylinders 1.3.5)?. Are the fuel trims on the 2 banks within 10% of each other?

Injectors are suspect as the p0175 (bank 2 - cylinders 2,4,6) occurred after they were replaced. Where were they were purchased? Unfortunately there are a number of poor quality injectors on amazon and ebay. One common issue is a cheap o-ring at the base of the injector that fails along with simply crappy injectors. A failed/damaged injector o-ring could be letting air in and cause the injectors on that bank to stay open open longer (more fuel).

Get rid of the Bosch O2 sensors, they do not play well with Chryslers. Suggest OE/NTK/Denso only. FWIW, chrysler applies a 2.5 volts bias on the ground to the sensor which tends to confuse the Bosch sensors.

 

Thanks so much for that response. I was actually reading about the O2 sensors and was putting in NTK when you responded. So, good timing.

The injectors were bought off of Amazon. Since your response...I ordered new OEM O-rings, and will most likely go back with factory injectors.

Really great info and I'll let you know the update.

 

Since you are pulling the plenum, I suggest replacing the intake plenum gaskets if they have flat spots or do not seem very flexible.

 

Dude!! I've been fighting this issue for over a month and your response was the answer. All DTC's are gone and the engine is running much better. There is a little fluctuation on the STFT still, but overall it's right around -3, or -5 when driving 60-Miles an hour. Thank you so much @ggoose !!!