Electronic Park Control Issue – 2017 Pacifica

Today we are looking at a 2017 Chrysler Pacifica Touring Plus equipped with a 3.6L V-6 engine and a 948TE transmission. This vehicle was towed to our shop, and upon dropping it off the tow truck driver said they needed to block the tires to keep it from rolling away.

While I got some help from our shop technicians, our service writer contacted the customer to get some information. We reached one of the owners and asked them if they could give us the events that led up to the vehicle's current state. The customer stated that they had driven the vehicle with no issues to a location where it sat for a couple of hours.

Upon finishing their business at the location, they started the car and drove off. When they arrived at their home when attempting to park, that is when the issue showed up. This vehicle has dial shift control on the dash, and when park was selected, the indicator would only flash without engaging Park. Shifting into other ranges seemed to work normally and the transmission would respond as expected and would engage forward gears and reverse. Back in the shop, we started the process of trying to figure out what was going on.

We started with using the special dipstick from the dealer and it was confirmed that the fluid level was full but dark in color. Next, we did a visual inspection to see if there was any obvious damage to the park release cable or the linkage itself. This all looked good. We moved on to disconnect the park release cable from its linkage at the transmission, and then accessed the emergency release inside the vehicle.

We were able to freely move the cable in both directions, so we were confident that a failed cable was not stuck or broken holding it out of park. We needed to dig deeper to find out if we had a mechanical or electrical component causing this issue. We attached our scan tool and checked for codes; unsurprisingly, the system generated code P1B13-00 with the definition of, "Park by Wire-Unintended Out of Park Position".

When watching the parameter for the range sensor, we could see that it would change to "Park" when Park was selected with the dash switch, so it appeared the command for Park to happen was there, and the range sensor could see what it needed to from the switch. Since we had the cable already removed from the linkage out at the transmission, we decided to try to move the linkage by hand, it felt solid; we could not move it at all. We had another one of these transmissions that had been removed from another vehicle on the bench and we were able to move the linkage on that unit.

It was decided that the next course of action would be to get authorization from the customer to remove the valve body cover and investigate the internal components. The customer was called and after explaining what we had done up to this point they gave us the OK to continue our investigation. Once the cover was removed, we could access the valve body and internal linkage. (Figure 1)

Nothing looked obviously out of place on our initial inspection. The park release lever was in the valve as it should have been. For park to engage, a few different things are going on. There is a park lock solenoid that is connected to the park lock valve that is spring-loaded, so if there is no hydraulic pressure from the park control solenoid, the transmission will remain in Park. Also, when the park lock solenoid is de-energized (such as when the ignition is off), the transmission will be in Park. When hydraulic pressure is applied through the park lock solenoid, the park lock valve mechanically moves the parking pawl linkage. (FIGS 2 & 3)

When we removed the park lock solenoid we found the reason for the bind-up in the linkage. The end of the solenoid has three tangs on it to hold the park lock valve when the vehicle is running and there is pressure acting on the valve, and this valve is energized and holds the linkage out of park. These were broken and stuck in the valve. (FIGS 4 & 5)

The owners of this vehicle use it constantly, and like most families, need it to be reliable. We contacted them with our findings, and with the fluid condition of the transmission and the mileage factored in the customer elected to go with a replacement transmission with a warranty. It took a little work, but we were happy to have been able to help the customer get a safe and reliable repair made. Long gone are the days of a simple linkage controlling park and other shift functions. We wonder what will be coming next.