2.5 Hybrid: P0811 code OBD2

[mav47]

I took delivery of a Hybrid Maverick Lariat two weeks ago. After driving a Prius for ten years (270k reliable miles) I love driving my new truck and the practicality it offers. In busy SoCal traffic, I can attest to the usefulness of the Lane Centering and Adaptive Cruise features, it is very helpful. On my daily 60 mile+ freeway commute, I am also getting truly stellar fuel economy: consistently 40-41 mpg door to door doing 71-73 mph on the freeway with a few miles of city traffic on each end.

However: at around 600 miles on the ODO, I got a check engine light after "stepping on it" a bit more than typical when merging onto the freeway. The light stayed on for a few stop/start cycles and the next day the light turned off. I had the Ford dealer scan the car and it reported:

P0811 - $7EE "Generic" - Excessive Clutch A Slippage

They cleared the code told me to report back if it returns. The service manager had not seen this particular code on the Maverick before.

Several days later, now with 1,500 miles on the odometer, I step on it again when merging uphill (close to 100% engine load) and the light comes on again. And a few start/stop cycles later it disappears. What I did notice is that when the light is on, engine power seems to be limited to 70-75%. I have not had the car scanned, but I assume it is the same code.

This P0811 code is generic of course, and it does not seem to be directly applicable to this Ford Hybrid drivetrain because it lacks any clutches.


>>>
Edit: turns out this assumption was wrong, there is indeed a safety clutch built into the damper between the engine and the transaxle, and indeed it is slipping when it shouldn't be. I thought I'd clarify this as then this thread makes more sense to readers going forward.
<<<


I read (courtesy www.dtcdecode.com) that this code comes on when there is a difference between the PCM measured engine speed and the transmission speed. Possible causes listed: Damaged Crank Position Sensor, Damaged transmission damper, or damaged engine shaft. All these are not specific to the hybrid so may or may not be applicable.

I will go back to the dealer and they may have to check with Ford, but thought it wise to check in with the community to see if someone else has had this P0811 error code on a Hybrid?

Thanks for any feedback!

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[Mark Rash]

There have been a few other reports of this same issue in the forums. It seems to almost always be associated with flooring it. Wonder if @Ford Motor Company has any thoughts on this?

 

[Aza]

Unfortunately, we have seen others report this code.

https://www.mavericktruckclub.com/forum/threads/fun-pauses-after-a-month.11668/

https://www.mavericktruckclub.com/forum/threads/hybrid-check-engine-light-comes-on.9398/

 

[mav47]

Thanks for the feedback everyone. I had not seen those other threads.

Multiple owners reporting this same P0811 code does imply that we're talking about a more "common" issue with these Hybrids. But there is no cause determined yet?

Some on those two threads talked about the transmission dampener (which I presume is located between the ICE and the HF45 planetary transmission) or the crank position sensor, basically the same items I found on DTCdecode.com.

I would think that engineers at @Ford Motor Company are already looking into this issue. I'll reach out to their user account on this site with my VIN info and a link to this thread.

 

[mamboman777]

I believe there is a safety clutch between ice and transmission.

 

[Airrun8]

Welcome to the p0811 club! My Maverick has been sitting at the dealership for 30 days with only 1,000 miles. They're still waiting on parts. No loaner vehicle offered. Definitely disappointed with the service I've gotten from Ford.

 

[projectvortex]

Welcome to the p0811 club! My Maverick has been sitting at the dealership for 30 days with only 1,000 miles. They're still waiting on parts. No loaner vehicle offered. Definitely disappointed with the service I've gotten from Ford.

What was your diagnosis? I have not seen this issue (yet) and I've really gunned it a few times merging onto a freeway (in sport mode even).

 

[Airrun8]

What was your diagnosis? I have not seen this issue (yet) and I've really gunned it a few times merging onto a freeway (in sport mode even).

All the service department said was that it was a "clutch slippage". I'm not mechanically savy but I don't think the Maverick hybrid has a clutch? They are replacing the engine damper. It sounds like they are not sure what's causing it and just doing what Ford told them too.

 

[Darnon]

All the service department said was that it was a "clutch slippage". I'm not mechanically savy but I don't think the Maverick hybrid has a clutch? They are replacing the engine damper. It sounds like they are not sure what's causing it and just doing what Ford told them too.

There's a damper assembly not unlike a clutch plate between the engine flexplate and transmission input shaft to allow for some slippage in the case of torque/resistance differential to prevent breaking things.

 

[Chris_G]

There's a damper assembly not unlike a clutch plate between the engine flexplate and transmission input shaft to allow for some slippage in the case of torque/resistance differential to prevent breaking things.

That sure doesn't sound like a fun repair.

 

[projectvortex]

All the service department said was that it was a "clutch slippage". I'm not mechanically savy but I don't think the Maverick hybrid has a clutch? They are replacing the engine damper. It sounds like they are not sure what's causing it and just doing what Ford told them too.

Many thanks. Obviously there will be many following this repair if you could keep this thread updated.

 

[abjbrtd]

Welcome to the p0811 club! My Maverick has been sitting at the dealership for 30 days with only 1,000 miles. They're still waiting on parts. No loaner vehicle offered. Definitely disappointed with the service I've gotten from Ford.

like you I can't understand how Ford didn't plan ahead for a world wide pandemic AND WWIII

What was your diagnosis? I have not seen this issue (yet) and I've really gunned it a few times merging onto a freeway (in sport mode even).

Hope they figure it out before the middle of the month (I have a buid week just no build day because I will be going WOT a lot

 

[stick]

A damper works to take out/smooth out the torque spikes from the ICE engine (not continuous but lots of little explosions!). so as we think of input shaft to damper to output shaft configuration, There will be a small expected difference between input and output shafts as the damper actually smooths out the output shaft speed. if there is something wrong with the damper, it will allow too much difference between the input shaft and output. If I had to guess, the sensors measuring shaft speed are picking that up. THink about 'flooring it' - worst case as the damper has to work the hardest to keep up to the torque change and handle the largest torque spikes. my guess is not a critical issue that will result in cascading failures, but rather a 'out of boundary'. Only risk (assuming some form of rubber) is damper is being worked at higher levels and could fail early. Unless Ford knows of critical failure that requires parking the vehicle until fixed, I would keep the car myself until parts are in - and ease off the flooring until fixed.

 

[abjbrtd]

Hope so, I've already spotted a couple 2.0s that need a demonstration of what electricity can do stoplight to stoplight

 

[Airrun8]

A damper works to take out/smooth out the torque spikes from the ICE engine (not continuous but lots of little explosions!). so as we think of input shaft to damper to output shaft configuration, There will be a small expected difference between input and output shafts as the damper actually smooths out the output shaft speed. if there is something wrong with the damper, it will allow too much difference between the input shaft and output. If I had to guess, the sensors measuring shaft speed are picking that up. THink about 'flooring it' - worst case as the damper has to work the hardest to keep up to the torque change and handle the largest torque spikes. my guess is not a critical issue that will result in cascading failures, but rather a 'out of boundary'. Only risk (assuming some form of rubber) is damper is being worked at higher levels and could fail early. Unless Ford knows of critical failure that requires parking the vehicle until fixed, I would keep the car myself until parts are in - and ease off the flooring until fixed.

Wow thank you for that explanation! You explained it better than anyone I've spoken to in the service department.

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