airline tech
Well-Known Member
- Joined
- Aug 24, 2022
- Threads
- 23
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- 3,245
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- Location
- Midwest - KS
- Vehicle(s)
- 2022 Ranger Lariat-Super Crew, Cactus Gray
- Occupation
- Aircraft Tech
First - Sorry for all the issues and hassleSo this is gonna be a long one. Buckle up.
First off, I've worked for FoMoCo at two different plants in KY for over 13 years.
My 2021 Ranger XLT FX4 started having pretty severe rough shifting issues around 35,000 miles. I took it to the dealership where I purchased it, and they told me that was the nature of the trans, but that there was a strategy update. The update was done and the learning module tables were reset.
Around 45k, the problems were right back, as bad as ever. On top of that, the trans dropped itself into neutral when I was trying to get out of a parking lot fast in heavy traffic. Hit the gas, heard a bang, rolled forward. Stabbed the breaks, and had to put it in park before it would go back into drive. Really lucky I didn't get hit. I I did some research and found one of the TSB's (not the most current). I called the original dealer, and was told that they wouldn't even be able to look at it for 4-6 months. I drive a lot. I knew I couldn't wait that long.
I called another dealership closer to me that came recommended. Took it in with a copy of the TSB, and gave them all the info on what was happening. They had it for a couple of days, and called me saying that they installed a new strategy (again) and reset the tables.
Around 2.5k later, the same problems and then some new ones. The shifts were harder, and the trans was hunting for gears. It didn't want to go into 10th, like it was stuck in 9th on the interstate. It would also stay in 10th and "lug" at low speeds (around 30-35mph). Stop and go rush hour traffic was a nightmare. Sudden stops would cause it to slam into lower gears, and sudden acceleration would do the same.
Took it back to the 2nd dealership, explaining what was going on. They performed the second step of the TSB (replacement/repair of the Valve body assembly). Along with clearing the tables for a relearn.
During all previous relearn periods, the truck shifted reasonably, definitely not smooth, but acceptably. This time was different. After around 500 miles, the trans started slamming into gears worse than before. Not as frequently, but significantly more violent. Also, the truck dropped out of gear into neutral again.
Back to the same (2nd) dealership. Two of the service writers stared at their PC monitor for around 10 minutes while I stood there waiting. Finally, one said "well the truck isn't showing any DTC's and we can't replicate your symptoms, so there's nothing we can do." I had already talked through the most current TSB, to make sure they knew about the next step. The updated CDF drum and bushing.
I asked if the truck had shown any codes before, and they said no. I asked if not, then why had they removed the valve body and reset the tables. They told me because they knew about that issue, and it was a courtesy. They claimed that Ford wouldn't pay for the warranty work without DTC's/replicated symptoms. I left the Ranger there.
I called the Union Dealer Liaison rep at my plant, who told me to call the Detroit Quality Claims Office. After a 45 minute conversation, the only thing they could tell me to do was take it to a different dealership. The whole TSB process would have to be started over.
The very next day, I get a call saying my truck was ready to be picked up. I asked what they had found and done. Their response was that they AGAIN resent the learning tables, the trans tech couldn't replicate my symptoms. I drove to the dealership, a conversation over the phone wouldn't cut it.
They said there was nothing else they could do, there were no DTC's and they couldn't replicate my symptoms. I argued with them for around 40 minutes, got nowhere. I told them to give me the truck, was left standing there, and then told by a different service writer that they were having trouble finding my vehicle. 15 minutes go by. Finally they found it, left with the paperwork and keys in the driver's seat.
The service writer who drove it up could tell that I had completely hit my limit, and told me that he himself felt it shift hard driving it through the lot. He gave me his cell number, and told me to text him through the weekend with updates on how it was driving.
Next day, the wrench/powertrain light pops up on the IP, and the truck won't go over 55mph. It's slamming into gears like someone is hitting it with a sledgehammer. Notifications are popping up on my phone. I text the service writer and he tells me to bring it back in.
I drop it off, get a call two days later, and the wrench/powertrain light is gone. No DTC'S. Symptoms can't be replicated. They resent the tables as a courtesy.
I show up at the dealership demanding to talk to the service manager. He has no answers. Nothing he can do.
A few days later, the wrench/powertrain light AND the check engine light turn on, and it goes into limp mode. AutoZone scanner shows code P0235.
I take it to another dealership (3rd). They won't even look at it because someone else has worked on it.
It's now sitting at the original dealership where I bought it, having to start the whole process over.
I have less than 5,000 miles left on the powertrain warranty.
I'm a 13 year Ford employee, and I can't even get known issues covered under warranty. God help a regular customer. This is the last new Ford I'll ever buy.
But I would look VERY HARD at the code P0235, and more than just scan - no code - its good
As I believe this is the ROOT CAUSE of ALL issues and how the PCM responds to that code or circuit issue (and it finally coded) with a hard fault.
P0235 - Is for the Turbo Charger Boost Pressure sensor, this sensor along with the MAP sensor can affect transmission shifting and fuel delivery issues.
So, in a what if scenario - if the Boost Pressure sensor was reading (Over Boost) pressure, the PCM would respond by reducing fuel delivery, the side effect is power loss and shifting issues.
Depending on the programming of the PCM the above power loss can also trigger the PCM to shift the transmission into neutral.
Being that this has been an ongoing issue and no codes, I suspect a wiring issue with the VREF circuit, so this is going to REQUIRE a wiring check with the importance of a harness shake test to isolate where the wires are either touching each other or ground.
I would defiantly replace the Turbo Charger Boost Pressure Sensor as precaution and do a cold (first) start of the day check on all the temperature sensors (should all match within a few degrees of each other)
Engine Temp (ECT) - IAT (Intake Temp) - IAT2 (MapT) this is the integrated (Map & Temp) sensor
and the CHT (Cyl Head Temps) and the (AAT) Ambient Air Temp- This is the temp you see on the Sync Screen (Mostly used for HVAC) control.
The most important of the Temp Sensors and the tie in for code P0235 is the IAT & AAT
They are on the Signal Return (VREF) for the Turbo Boost Press sensor.
By chance did you happen to notice if the (Sync) screen temp display was either blank or way off from the actual temp when any of this was happening?
This would possibly indicate and confirm that the issue is on that circuit.
It is also a very good idea to run a Live Data monitor and dig into the Ref data (Normal) readings and crosscheck the actual readings on the truck.
Mainly the MAP-BARRO / Turbo Boost Press
I have a feeling the issue is on this circuit and the code you pulled, needs to be checked in depth and the actual PID readings monitored.
Focus on the (top) half of the diagram.
PCM (5-Volt) VREF feeding the (TCBP) sensor
Signal Return: Ties in AAT & IAT
The actual boost pressure reading is being sent back to the PCM on Pin #1 (TCBY)
If there is a short or faulty sensor in the circuit all sensors could be affected and give improper readings to the PCM an induce the issues you are having.
I will also NOTE that the code P0235 is a (Circuit Issue) code for the TCBP sensor, and I have a hunch that the code you finally have is an indication of a highly possible avenue to find a verified fix for all of the issues, It's not the transmission, it's in the PCM control of the transmission. I could be WRONG, but this code is something that needs investigated - DEEPLY and not overlooked.
I truly hope the techs will agree and think outside the box on this (outside a service manual diagnosis) - Boost Pressure affects engine performance, Engine Performance affects Transmission Shifts - (Line Pressure) being affected - Line Pressure affects shift points and can drop the transmission into neutral as a result.
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