Truck died making a right turn....

[Bigsack]

Guys report it to NHTSA. This is BS, The truck should not be getting confused during a turn. It is a safety issue.

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[Switzguy]

How much gas was in the tank when this happened?
Could be starving the LPFP.

 

[Trimjb]

How much gas was in the tank when this happened?
Could be starving the LPFP.

My tank had plenty of gas in it.

 

[Switzguy]

Knowing that the truck stalls specifically while slowing down for a turn with Auto Start-Stop manually turned off heavily narrows the issue down. For a brand-new 2025 Ford Ranger, this combination points directly to a mechanical-to-electronic communication failure, likely involving the Torque Converter Clutch (TCC) or a critical grounding circuit.
When slowing to turn, the vehicle undergoes a multi-system shift: engine RPMs drop, the 10-speed automatic transmission rapidly downshifts, and the electric power steering draws peak amperage as you turn the wheel.
The primary causes for this exact behavior include:

1. Torque Converter Clutch (TCC) Failing to Disengage
The 10-speed transmission (10R80/10R60) uses a torque converter clutch to lock the engine and transmission together at speed for maximum fuel efficiency. [1]

• The Glitch: As you brake and slow down to make your turn, the transmission's valve body or electronic TCC solenoid must disengage the clutch to let the engine idle freely. [1, 2]
• The Result: If the clutch sticks or responds too slowly, the weight of the decelerating truck forces the engine's RPMs below idle speed, instantly stalling it. This is exactly like stopping a manual transmission truck without pressing the clutch pedal. [1, 2]

2. High-Draw Steering Voltage Drop
The 2025 Ranger uses Electronic Power-Assisted Steering (EPAS). Turning the wheel at low speeds or while decelerating demands a massive spike in electrical power.

• The Glitch: If there is a loose ground wire on the frame or a slightly loose battery terminal, this sudden amperage draw starves the Engine Control Module (ECM) of voltage for a millisecond.
• The Result: The ECM panics due to the brief power loss and shuts the engine down instantly. [1]

3. Transmission Downshift Strategy Fault
Ford’s 10-speed automatic relies heavily on "Adaptive Learning" software to predict shifts based on your driving habits. [1, 2]

• The Glitch: When braking into a corner, the truck is trying to rapidly downshift through multiple gears (e.g., from 5th down to 2nd). If the computer gets confused by the sudden drop in throttle input combined with braking, it can lag between gears, dropping the engine speed too low to maintain combustion. [1, 2, 3]

Immediate Steps to Take

1. Test the "Neutral" Trick: The next time you are approaching a slow turn, safely shift the truck into Neutral (N) right before you begin braking and turning. If the truck does not stall in Neutral, your stalling issue is 100% related to the transmission/torque converter failing to unlock properly under load. [1, 2]
2. Look for the "A" with a Slash: When it stalls, look at your digital dashboard cluster. If you see a gray "A" with a line through it, the truck's computer thinks Auto Start-Stop is what caused the shutoff, meaning a sensor glitch is overriding your manual button selection. [1, 2]
3. Take it to the Dealer for a Module Flash: Because your truck is a 2025 model under full factory warranty, take it straight to Ford. Tell the service advisor: "The vehicle is stalling upon deceleration during low-speed cornering with Auto Start-Stop off, acting like a stuck torque converter clutch." Ask them to check for any PCM/TCM (Powertrain/Transmission Control Module) software updates or to clear the transmission's adaptive tables. [1, 2]

To help narrow this down further before you head to the dealer:

• Does the engine sputter and shudder right before dying, or does it shut off instantly and cleanly like someone turned the key?
• Do you notice any harsh clunking or jerky shifting right before the stall happens? [1, 2]

 

[TerryRHan]

Read post #33 and #43. In my opinion/experience it points to the traction control. To confirm it, once it acts up run the truck through the exact turning scenario with the traction control off and see if the results are different.

 

[Switzguy]

Did any of the screens turn off or just the AC stopped? How long does it take for it to turn back on?

 

[Trimjb]

For me in a left turn, the engine did not shut off. AC still on and power steering active.
I just had zero throttle response for a few seconds. I steered off the road on to shoulder and the throttle responded again. The auto start was off.
I'm glad no one was behind me.

 

[Bigsack]

Read post #33 and #43. In my opinion/experience it points to the traction control. To confirm it, once it acts up run the truck through the exact turning scenario with the traction control off and see if the results are different.

The turn where my truck displayed the behavior discussed, I travel it everyday to work and have made that same turn multiple times and the truck hasn't duplicated the problem since.

 

[Bigsack]

Did any of the screens turn off or just the AC stopped? How long does it take for it to turn back on?

For me, I "think" the truck shut off. I remember everything going quiet, the HVAC fan stopped, etc. Lasted only a few seconds. Truck regained power while my brain was still processing what had happened.

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