Hello!
My 2011 Jeep Liberty's check engine light went on. Code showed high pressure on transmission line (P0869). I took it to a transmission shop. They replaced the pcm. When I drove my Jeep home, the check engine light came on again. However, it seemed to be running fine. I was not happy the way I was treated at the shop, so I took it to the dealership where I purchased it. They replaced several things on the transmission including the valve body. They also put in a new power train control module (PCM). Jeep ran perfect, but check engine light would not turn off. They got Chrysler involved. Although they gave me a free loaner car, they had my Jeep for 7 weeks. Chrysler paid to have the transmission rebuilt. The check engine light is still on. The Chrysler "Star Tech" won't be around until March. Chrysler is still paying for everything. We asked if I could have my Jeep back until the tech shows up in March. Chrysler said o.k. I have been driving it for a few days. It works perfect, however the check engine light is still on with the same code. Because it was warm out today, I tried to use the air conditioner. It blows warm air. It worked perfect before I took it in. Could the PCM have something to do with the air conditioner not working? My Jeep has 60,000 miles on it and I love it.

Thank you for any help! I feel lost...

P0869 Transmission fluid pressure (TFP) sensor - high. Possible causes; Wiring short to positive, TFP sensor, ECM/PCM.

Inadequate Transmission Control Output voltage can also cause DTCs P0846, P0869, or P0871 to set.
This may sound simple but crawl under the rig and look for a chafed wire. Pay close attention around the exhaust manifold.

For the other question, yes it could.
But; Check your coolant level. Disconnect the Neg(-) battery cable for 10 minutes(computer reset).
Is the A/C clutch cycling?
Dumb questions but got to ask. Is the Mode(floor, vents, defrost) setting in one of the A/C modes? Does the A/C light turn on/stay on, on the dash?
Does the electric radiator fan cycle on/off?

_________________
07 KA Light Khaki, Manual trany.
2.5" Adjust-A-Strut JBA lift, Euro taillights,
Home made; Front Tilt Hood, Roof Rack, RAM Air, & CAI.
ESP Off Switch
Take a ride on the Trō side!

Hi wrapperc,

Sorry to hear about your ongoing concerns! I'd recommend letting your dealership know about your AC concern so they can let the Field Tech who is coming out in March know ahead of time. Please don't hesitate to reach out if you have any additional concerns after the Field Tech examines your vehicle.

Andrea
Jeep Social Care Specialist

The AC condenser and Trans oil cooler are the same part. If your issues are related, my guess is you have a restriction in the trans oil cooler that also is affecting the AC condenser.

_________________
2008 Liberty Sport
OME Lift, JBA A-Arms + Track Bar
245/75/16 Nokian Rotiiva AT Plus
Numerous junkyard upgrades

They are physically connected, but the trans cooler is separate from the condenser. Two different chambers. The condenser is in the bottom 2/3 and the trany cooler is in the top 1/3.
As long as there is adequate air flow thru the fins, neither should affect the others function. Unless the trany is seriously overheating. But, if that were the case, it would set an additional/ different code along with the P0869.

_________________
07 KA Light Khaki, Manual trany.
2.5" Adjust-A-Strut JBA lift, Euro taillights,
Home made; Front Tilt Hood, Roof Rack, RAM Air, & CAI.
ESP Off Switch
Take a ride on the Trō side!

I was thinking rock chips/kinked lines. Good point on the overheating though. Could it be they evac'd the AC lines to replace the TOC/Condenser? It may even be unrelated. Anyway below is what the service manual calls out.

Theory of Operation

Line pressure is measured by the Line Pressure Sensor (LPS) and regulation is achieved by changing the duty cycle of the Pressure Control Solenoid (PCS) controlled by the Transmission Control System. (5% duty cycle = solenoid off = Max line pressure, 62% duty cycle = solenoid on = Min line pressure). The Transmission Control System calculates the desired line pressure based on inputs from both the engine and transmission.

The Transmission Control System calculates torque input to the transmission and uses it as the primary input to the desired line pressure calculation. This is called Torque Based Line Pressure. In addition, the line pressure is set to a preset level 827 or 931 kPa (120 or 135 psi) during shifts and in Park and Neutral to ensure consistent shift quality. The desired line pressure is continuously being compared to the actual line pressure. If the actual line pressure is consistently higher than the highest desired line pressure ever used in the current gear, the line pressure high DTC P0869 will set.

When Monitored:
Continuously while driving in a forward gear.

Set Condition:
The PCM continuously monitors Actual Line Pressure. If the Actual Line Pressure reading is greater than the highest Desired Line Pressure ever used in the current gear, while the Pressure Control Solenoid duty cycle is at or near its maximum value (which should result in minimum line pressure), the DTC will set.


Possible Causes

(F856) 5-VOLT SUPPLY CIRCUIT OPEN
LINE PRESSURE SENSOR CONNECTION
(T118) LP VFS CONTROL CIRCUIT OPEN
(F856) 5-VOLT SUPPLY CIRCUIT SHORT TO GROUND
(T118) LP VFS CONTROL CIRCUIT SHORT TO GROUND
TRANSMISSION CONTROL OUTPUT CIRCUIT
LINE PRESSURE SENSOR
STUCK OR STICKING MAIN REGULATOR VALVE
POWERTRAIN CONTROL MODULE

_________________
2008 Liberty Sport
OME Lift, JBA A-Arms + Track Bar
245/75/16 Nokian Rotiiva AT Plus
Numerous junkyard upgrades

In theory the dealer should have checked all the above as well as tracing wires/plugins both physically and with a meter/light. Its strange the dealer did not try to flash the PCM or replace it. That would have been less $ then a trany rebuild.

It is possible they evacuated the A/C and did not recharge it, but also "in theory" that should set another code.
Too bad the OP does not have more info to keep us guessing.
Then there is always the lemon law, as a last resort...

_________________
07 KA Light Khaki, Manual trany.
2.5" Adjust-A-Strut JBA lift, Euro taillights,
Home made; Front Tilt Hood, Roof Rack, RAM Air, & CAI.
ESP Off Switch
Take a ride on the Trō side!

Thank you to everyone who responded.
I will be turning in my Jeep to the dealership this Monday for the Chrysler Star tech to look at again. The pcm was replaced twice. The first time it was replaced with an aftermarket pcm at a transmission shop. The check engine light remained on. I decided to take it to the dealership where I bought it. They informed me that only dealerships could properly replace powertrain control modules, due to the fact that they would not have access to the updated programs that need to be downloaded.


The dealership found a bad ground wire. They fixed it and then replaced the valve body. After that didn't work, they replaced the pcm with a factory pcm. The engine light with the same code (0869) came back. Chrysler told them to rebuild the transmission. The engine light returned with same code. The Chrysler Star tech came in and told the dealership to obtain a special diagnostic scanner that few dealerships have. When it was scanned the information was sent to Chrysler. Chrysler told them to replace the pcm. The dealership told them that they already replaced the pcm.

We brought the Jeep home to wait for the Chrysler Tech to arrive. It is running great, except the check engine light is on and I discovered that the air conditioner blows warm air. The ac clutch is not cycling, but there is voltage at the clutch (14 volts) It was working great before all of this. This is where I am today.

Again, thank you for all for your input. There is still snow and ice on the ground and I sure will miss my Jeep!

Well, the Star tech told the dealership to put in a brand new transmission. Chrysler is paying for it. Hopefully this will stop the check engine light from coming on with the same code!
Oh, and the dealership said that my Jeep showed air conditioner codes when I brought it in. This was never mentioned to us. It is a little odd that the codes were checked before we brought it in and nothing about the air conditioner came up. They originally gave a list of things that needed to be serviced. We paid to have a tune-up, the transmission fluid changed and the front rear differential and transfer case pm'd. They also mentioned that we needed rear brakes, which we said we would do ourselves. Absolutely nothing was mentioned about the air conditioner. Will air conditioner codes show up on hand scanners you can purchase for home use or when Auto Zone checks codes? Both of these showed only the transmission code. (P0869)

Thank you for your advice!

Some codes are buried deep in the computers. Most general code readers can not get to them. So yes, it is possible the codes were there and just not seen except by a Jeep tech.
However, All authorized Jeep dealers/service Depts should have the ability to read these codes. So why it was not mentioned before is beyond me. Unless they did not check for codes, and/or they are just trying to cover their rears...

_________________
07 KA Light Khaki, Manual trany.
2.5" Adjust-A-Strut JBA lift, Euro taillights,
Home made; Front Tilt Hood, Roof Rack, RAM Air, & CAI.
ESP Off Switch
Take a ride on the Trō side!

Hello! Thank you for your info on the codes! I didn't know home scanners didn't show everything. The dealership called yesterday after another week in the shop. Bad news yet again The brand new transmission did not fix the problem. The code is still presenting. They told me they will call Chrysler and let us know what will happen next. I am so worried. They have been trying to fix it for months now.

Some people have mentioned the Lemon Law. However, it was not brand new when I bought it. This Jeep is very important to me. It is the nicest vehicle I have ever owned. I paid cash for it with money my mother left me when she died. I am on the road at 3:00 a.m. in the morning for my job. I never had a vehicle with 4WD. I couldn't believe how awesome it was not to be worried about going through snow storms before the snow plows hit the roads! My Liberty went through the snow just like a hot knife through butter! I love everything about it including the color, Blackberry Pearl.

Hopefully, somehow, they will figure out the problem. I am definitely exhausted thinking and worrying about it. Thanks again to all!

There are only so many things that will cause this code. and if it is not the trany, then that leaves only the electronics and wires.
I'd ask for a new wire harness, since they already replaced the PCM.
EDIT:Something you can DYI check if you like.
On the passenger side firewall is a ground strap that runs from the firewall to a bell housing bolt on the trany.
Check for corrosion on the firewall side.
You could also add an additional heavy duty ground wire/strap from the trany to any part of the body or directly to the Neg battery post. This would eliminate the possibility that the bad ground wire they "fixed" wasn't actually fixed.

_________________
07 KA Light Khaki, Manual trany.
2.5" Adjust-A-Strut JBA lift, Euro taillights,
Home made; Front Tilt Hood, Roof Rack, RAM Air, & CAI.
ESP Off Switch
Take a ride on the Trō side!

We keep thinking it's got to be something with the wiring. I forgot to mention that they did replace the wiring harness. Thank you for the tip about the ground wire! We will definitely try that if I get it back!

I wonder if they forgot to connect the aforementioned ground strap. It is an easy one to over look especially from below. Not to mention it is a royal pain to get on because it is such tight quarters... I almost forgot mine when I did a clutch replacement.
Anyway, keep us posted on the progress.

_________________
07 KA Light Khaki, Manual trany.
2.5" Adjust-A-Strut JBA lift, Euro taillights,
Home made; Front Tilt Hood, Roof Rack, RAM Air, & CAI.
ESP Off Switch
Take a ride on the Trō side!