Is it possible to avoid a PCS failure with a workaround?

[ted46]

I wonder if it’s possible to save the MOS FETs that are burning out by charging at a lower current rate, say 15 A or 20 A max.
At least until they get this run of PCS failures managed better.

My previous car, a hybrid had a similar problem that was eventually solved by simply replacing the ‘bad’ production run of MOSFETs:
”the Lexus RX400h had a notable powertrain recall involving the hybrid inverter’s intelligent power module, which uses transistors/MOSFET-like power semiconductor circuitry. Toyota/Lexus recalled certain 2006–2007 RX400h vehicles because heat-related stress in the inverter assembly could damage those transistors and cause warning lights, limp mode, or in some cases shutdown while driving.”

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[UberNoob]

Doubt it, but you’re welcome to try it out and let us know. Ideally one would want it to fail inside the warranty window vs an out of pocket cost.

 

[Galvatron]

I used to charge at a lower amperage, thinking it would be less strain on the battery. However, after considering other factors like how the heat pump has to run during charging to maintain proper battery temperature, I decided the longer it takes to charge the more strain it would be overall on the system. I could be wrong, just my logic.

 

[rsilvers]

If you have the old part you want it to fail sooner because they have not guaranteed extending the coverage of it.

That being said, lower current probably would prolong the life.

 

[Ivessm]

Nope, lowering the AC charge amps does nothing to avoid the PCS failure. I set my AC charging amps @ 24 amps since New in 2024 and still had the PCS failure a few months ago.

 

[Galvatron]

Nope, lowering the AC charge amps does nothing to avoid the PCS failure. I set my AC charging amps @ 24 amps since New in 2024 and still had the PCS failure a few months ago.

What are your thoughts on lower vs higher amp charging for whole system longevity? Do you think it's better to do 24 amps and run the heat pump for more hours or 48 amps and get done faster?
I know heat is the enemy to batteries but is there that much more at 48 if the heat pump is doing it's job? I feel like the heat pump longevity is at greater risk due to extended use at 24A.

 

[Ivessm]

What are your thoughts on lower vs higher amp charging for whole system longevity? Do you think it's better to do 24 amps and run the heat pump for more hours or 48 amps and get done faster?
I know heat is the enemy to batteries but is there that much more at 48 if the heat pump is doing it's job? I feel like the heat pump longevity is at greater risk due to extended use at 24A.

I go with 24 amps AC charging because I'm not in a rush to have it recharged. Overnight is more than enough time to recharge @ 24 amps. Also the 24 amp charging runs cooler from breaker panel to Wall Connector to truck. When in @ 48 amps the cable from the Wall Connector is warm and the ants love it and parade up and down the cable and to the truck.

I've never considered or even thought of any effect on the heat pump between 24 & 48 amp AC charging. It's a mechanical device. It could fail tomorrow or never fail, it's not something I consider.

 

[ted46]

I used to charge at a lower amperage, thinking it would be less strain on the battery. However, after considering other factors like how the heat pump has to run during charging to maintain proper battery temperature, I decided the longer it takes to charge the more strain it would be overall on the system. I could be wrong, just my logic.

Doubt it, but you’re welcome to try it out and let us know. Ideally one would want it to fail inside the warranty window vs an out of pocket cost.

I may be spoiled by the Lexus experience, mine never failed but they pro-actively replaced the part anyway. I will lookup the warranty on the PCS. Thanks, that was a helpful concept.

Nope, lowering the AC charge amps does nothing to avoid the PCS failure. I set my AC charging amps @ 24 amps since New in 2024 and still had the PCS failure a few months ago.

That is good information. Thanks.

 

[ted46]

From Grok today 4.25.26

Yes, the exact component failing in Cybertruck PCS (Power Conversion System, also called PCS2) issues is the MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors)—specifically the AC charging MOSFETs/transistors on the board.


The PCS is the integrated power electronics module that combines the on-board charger (for AC Level 2/home charging) and the DC-DC converter (which steps down the high-voltage battery pack to power the truck’s 48V low-voltage systems). It also handles Powershare (V2L/V2H) capabilities.


Why MOSFETs?


Early Cybertruck PCS units (primarily Foundation Series and production up to roughly July 30, 2024) used a specific batch of MOSFETs prone to thermal fatigue. Under repeated high-load heat cycles (especially at full 48A AC charging), these transistors micro-fracture or delaminate internally, leading to failure. This is the root cause confirmed across owner forums, service data, and detailed reports.


Failures typically start with just the AC-side MOSFETs blowing (DC Supercharging usually still works, as it bypasses that circuitry). Later stages can trigger broader issues like HVDC overcurrent trips.


Common symptoms and fault codes include:


• “AC Charging Unavailable” or reduced speeds (e.g., drops to 16–32A or zero).


• Powershare (V2L/V2H) errors.


• Codes like PCS2_a094, PCS2_a095, or PCS2_a137_cycBmosfetHealthCheckFailed.


• Sometimes 48V battery drain or unrelated-looking alerts (e.g., speed limited).


Tesla replaces the entire PCS module (not just the individual MOSFETs, as it’s a sealed assembly). Parts have been backordered recently, causing repair delays (some owners waiting weeks), but Tesla is covering free Supercharging as a goodwill gesture and pushing firmware updates to restore DC fast charging in the meantime.


This is distinct from the earlier NHTSA drive inverter recall (which also involved MOSFETs but was a separate campaign for ~2,400 early trucks).


Who is affected?


It’s most common in early 2024–early 2025 builds. Later trucks (post-July 2024) use improved MOSFETs and show far fewer failures. If your truck is still under warranty (4 years/50k miles standard), replacement is covered at no cost.


Owners are tracking this closely on forums like Cybertruck Owners Club, and Tesla service is handling cases case-by-case (no full fleet recall issued yet for the PCS itself).


If you’re seeing any of the symptoms or codes, open a service request in the Tesla app right away—many are getting proactive replacements even before total failure. Monitoring AC charging rates and Service Mode alerts is the best early warning.

 

[HaulingAss]

I wonder if it’s possible to save the MOS FETs that are burning out by charging at a lower current rate, say 15 A or 20 A max.
At least until they get this run of PCS failures managed better.

My previous car, a hybrid had a similar problem that was eventually solved by simply replacing the ‘bad’ production run of MOSFETs:
”the Lexus RX400h had a notable powertrain recall involving the hybrid inverter’s intelligent power module, which uses transistors/MOSFET-like power semiconductor circuitry. Toyota/Lexus recalled certain 2006–2007 RX400h vehicles because heat-related stress in the inverter assembly could damage those transistors and cause warning lights, limp mode, or in some cases shutdown while driving.”

I doubt it, I've been charging at 48A since new over 2 years ago and I haven't had any MOSFET failures. I think it's luck of the draw who gets the weaker MOSFETs.

 

[mongo]

From Grok today 4.25.26

Yes, the exact component failing in Cybertruck PCS (Power Conversion System, also called PCS2) issues is the MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors)—specifically the AC charging MOSFETs/transistors on the board.


The PCS is the integrated power electronics module that combines the on-board charger (for AC Level 2/home charging) and the DC-DC converter (which steps down the high-voltage battery pack to power the truck’s 48V low-voltage systems). It also handles Powershare (V2L/V2H) capabilities.


Why MOSFETs?


Early Cybertruck PCS units (primarily Foundation Series and production up to roughly July 30, 2024) used a specific batch of MOSFETs prone to thermal fatigue. Under repeated high-load heat cycles (especially at full 48A AC charging), these transistors micro-fracture or delaminate internally, leading to failure. This is the root cause confirmed across owner forums, service data, and detailed reports.


Failures typically start with just the AC-side MOSFETs blowing (DC Supercharging usually still works, as it bypasses that circuitry). Later stages can trigger broader issues like HVDC overcurrent trips.


Common symptoms and fault codes include:


• “AC Charging Unavailable” or reduced speeds (e.g., drops to 16–32A or zero).


• Powershare (V2L/V2H) errors.


• Codes like PCS2_a094, PCS2_a095, or PCS2_a137_cycBmosfetHealthCheckFailed.


• Sometimes 48V battery drain or unrelated-looking alerts (e.g., speed limited).


Tesla replaces the entire PCS module (not just the individual MOSFETs, as it’s a sealed assembly). Parts have been backordered recently, causing repair delays (some owners waiting weeks), but Tesla is covering free Supercharging as a goodwill gesture and pushing firmware updates to restore DC fast charging in the meantime.


This is distinct from the earlier NHTSA drive inverter recall (which also involved MOSFETs but was a separate campaign for ~2,400 early trucks).


Who is affected?


It’s most common in early 2024–early 2025 builds. Later trucks (post-July 2024) use improved MOSFETs and show far fewer failures. If your truck is still under warranty (4 years/50k miles standard), replacement is covered at no cost.


Owners are tracking this closely on forums like Cybertruck Owners Club, and Tesla service is handling cases case-by-case (no full fleet recall issued yet for the PCS itself).


If you’re seeing any of the symptoms or codes, open a service request in the Tesla app right away—many are getting proactive replacements even before total failure. Monitoring AC charging rates and Service Mode alerts is the best early warning.

Grok is aggregating pop wisdom and is conflating the inverter recall (even though it differentiates that later).
The error code is MOSFET health, it could be the MOSFET, it could be the gate driver, it could be the monitoring circuitry, it could be PCB, it could a power supply or discrete passive component, it could even be the software.

 

[Art138]

I let mine sit at 7 amps for charging inasmuch I don’t use the truck every day. Still no issues knock on wood. My garage in the summer sees temps of 100 degrees. There has to be a better explanation for these failures.

 

[Willinak]

Nope, lowering the AC charge amps does nothing to avoid the PCS failure. I set my AC charging amps @ 24 amps since New in 2024 and still had the PCS failure a few months ago.

Interesting...test sample of one, but still you have me wondering. I checked my VIN thru a popular online site, and it said my VIN was an affected group so I tried to set up an appointment to have its checked out, but they took my appointment off saying my VIN was not affected. What to believe?

 

[HaulingAss]

Interesting...test sample of one, but still you have me wondering. I checked my VIN thru a popular online site, and it said my VIN was an affected group so I tried to set up an appointment to have its checked out, but they took my appointment off saying my VIN was not affected. What to believe?

Is your question really who to believe, a "popular" online site or Tesla?

I mean Tesla obviously has the most data, and the most accurate data and they have no real incentive to lie. Even Tesla doesn't know for a fact which ones will fail and which ones won't, they can only put you in a higher or lower risk category.

 

[Willinak]

Is your question really who to believe, a "popular" online site or Tesla?

I mean Tesla obviously has the most data, and the most accurate data and they have no real incentive to lie. Even Tesla doesn't know for a fact which ones will fail and which ones won't, they can only put you in a higher or lower risk category.

Good points, however if true "Even Tesla doesn't know for a fact which ones will fail” it’s obvious this is not a robust design. It’s more than just a bad batch of MOSFET’s and probably should be a recall.

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