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Exhaust Heat Exchanger

bp1954fromca

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There's some reports that the overheating alert and subsequent derating of the motor torque is not indicative of the actual coolant temps.
In other words, the truck really isn't overheating, but it will respond to the programming as if it is.

I don't know how true that is, but it kinda makes sense because the faulty servo valve signal is what triggers the response, rather than the coolant temp sensors themselves.

Or at least that's one scenario that has been reported. Regardless, the truck can't be operated normally, as a result. It's a lousy situation for sure.
Waiting on parts would be far less frustrating if Ford or their dealer network had a work around while waiting for parts. The fact that they cannot or will not have temporary fix will only lose customers. The powerboost I have is the best vehicle I have owned to this point but the service from ford’s dealer's will make me question owning another ford.
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amschind

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I'm actively working to delete the stupid heat exchanger. Based upon a lot of discussion on this forum and elsewhere, it appears that the sole function is slightly more rapid cabin heat in cold temperatures. MegaOhm is working on an electrical dongle to plug into the truck side wiring harness which controls the heat exchanger valve. I built a bypass circuit which connects between the in/out temperature sensors (as they are both just barbed fittings for 3/8" heater hose). I have the parts and could probably make the electrical part myself from a motorcycle exhaust tuning dongle, but I see no need to risk shorting something out when I can wait and buy the part ready to go.

TLDR: MegaOhm is doing the hard part with the wiring, which will be plug and play when ready (and should be $50-100 based upon the cheapo parts cost anyway). The coolant bypass circuit is really easy if you buy a heater bypass kit off Amazon (the pre-bent U heater hose is the useful part). Total cost if the MegaOhm part is $100 would be about $170 for the full bypass worst case.
 

amschind

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Does anyone have the correct part number for the exhaust heat exchanger for the 2021 Powerboost? The dealer sent in the pn 5A212 and warranty denied it saying it was an exhaust pipe and that number does cover exhaust pipes for many vehicles but the hybrid is different. Not just what is pictured in the red circles but the entire unit. Thanks.
1691528836708.png
The resonator and heat exchanger are all one part which is replaced as a unit. It bolts up to exhaust fittings up and downstream. It is NOT a purely exhaust part, but has exhaust components irreversibly built into it. The non-hybrid trucks us an almost identical part, which is the resonator and a section of exhaust pipe with no heat exchanger. We've found the part number before, and it is buried within the giant heat exchanger failure threads.
 
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Mcbutter

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I'm actively working to delete the stupid heat exchanger. Based upon a lot of discussion on this forum and elsewhere, it appears that the sole function is slightly more rapid cabin heat in cold temperatures. MegaOhm is working on an electrical dongle to plug into the truck side wiring harness which controls the heat exchanger valve. I built a bypass circuit which connects between the in/out temperature sensors (as they are both just barbed fittings for 3/8" heater hose). I have the parts and could probably make the electrical part myself from a motorcycle exhaust tuning dongle, but I see no need to risk shorting something out when I can wait and buy the part ready to go.

TLDR: MegaOhm is doing the hard part with the wiring, which will be plug and play when ready (and should be $50-100 based upon the cheapo parts cost anyway). The coolant bypass circuit is really easy if you buy a heater bypass kit off Amazon (the pre-bent U heater hose is the useful part). Total cost if the MegaOhm part is $100 would be about $170 for the full bypass worst case.
Anymore updates you're able to give about bypassing? Just had a CEL for P2C23, which is dealing with a mismatch for from what the servo sees and it's actual position. Read from the longer thread about all the issues. Would love to bypass this thing.
 

Snakebitten

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I'm guessing the bypass project is still on hold or it would be all the rage on the forum. :)

Regardless, the exhaust heat exchanger noise has certainly died down significantly.
 

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Mcbutter

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I'm guessing the bypass project is still on hold or it would be all the rage on the forum. :)

Regardless, the exhaust heat exchanger noise has certainly died down significantly.
Good point on that. Just got the dreaded leak this Friday. Got some pipes on order. Have lived with waiting till the engine gets the coolant hot for years so I'd definitely bypass and not think again.
 

Mosey

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I am curious if the 2024s have the same design. If they do then someone needs to get fired.
 
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amschind

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Anymore updates you're able to give about bypassing? Just had a CEL for P2C23, which is dealing with a mismatch for from what the servo sees and it's actual position. Read from the longer thread about all the issues. Would love to bypass this thing.
Will at MegaOhm was out of action for a bit. I am now the holdup, as we are trying to build a bypass servo that will plug directly into the factory harness without chopping up the factory harness and soldering in a plug. He asked me for a pic of the plug a few weeks ago and I have been busy with other stuff. I bought a second servo to destructively disassemble so that I can verify which wire on the servo is which (Power, ground, servo control and servo sensor). I have the factory wiring diagram, so those are the only remaining issues.

I am also building anew coolant bypass circuit without any junctions or U joint, just a loop of heater hose. It will be physically bigger, but There is space for it to sit tucked away, so I think that fewer joints will be a boon to reliability

YOU can supply the one remaining piece of info that I need. I won't be able to avoid a temperature mismatch on the in/out temperature sensors when the truck expects the exhaust to heat the coolant, and I assume that your truck is throwing that code as well. I would really like to verify that the temp mismatch code won't put the truck into limp mode, or this effort would just automatically cause limp mode.

I am still working on this, but life tends to get in the way.
 

Mcbutter

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Will at MegaOhm was out of action for a bit. I am now the holdup, as we are trying to build a bypass servo that will plug directly into the factory harness without chopping up the factory harness and soldering in a plug. He asked me for a pic of the plug a few weeks ago and I have been busy with other stuff. I bought a second servo to destructively disassemble so that I can verify which wire on the servo is which (Power, ground, servo control and servo sensor). I have the factory wiring diagram, so those are the only remaining issues.

I am also building anew coolant bypass circuit without any junctions or U joint, just a loop of heater hose. It will be physically bigger, but There is space for it to sit tucked away, so I think that fewer joints will be a boon to reliability

YOU can supply the one remaining piece of info that I need. I won't be able to avoid a temperature mismatch on the in/out temperature sensors when the truck expects the exhaust to heat the coolant, and I assume that your truck is throwing that code as well. I would really like to verify that the temp mismatch code won't put the truck into limp mode, or this effort would just automatically cause limp mode.

I am still working on this, but life tends to get in the way.
Really appreciate all the info and work you've done up to now. I was about 30 miles from my home when I noticed the CEL. I'm not sure how long it could have been there from that drive, roughly 70 miles total. I never lost any power or went into limp mode for this code on the mismatch.
 

Mosey

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p2c23 is back again, about one year after the last heat exchanger replacement for the same code. Surely Ford has a permanent fix? I am almost out of warranty and this is getting old. Would this code be an emissions related problem?
 
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eharri3

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Here to join the faulty heat exchanger club.

2021 xlt 4x4 with 22k.

Powertrain fault/reduced power came up leaving the driveway a week and a half ago. Went away when I turned it off and on and never came back on. A week later the dealer read it and said I need a heat exchanger. They ordered on Friday, it got here Monday.

No driveability issues at all. Coolant level where it needs to be and no leaks detected so it's not the fittings. I had the ICE to EV and back squeak before it but the noise actually has not been present since I briefly got the code.

Have an appointment to get it replaced tomorrow. The truck is driving perfectly, has been the entire time. The Squeak has come and gone for several months but never happened at service so getting the code is actually lucky as it ended me having to argue about or prove whether there is a problem.

I asked them to listen for the squeak in addition to reading the code and they never heard it and told me they'll keep checking, not realizing it's the same problem.
 
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Mosey

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Thanks snakebitten. I understand parts can break and wear, but this is my fourth time dealing with a heat exchanger-related issue, and I am still under warranty. What is going to happen over the next 5 years? I would think this part would be upgraded to solve this. Becoming disheartened.
 

TheGoatman

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I don’t understand why it keeps happening in one truck and never happens with an old unrevised part on another. That being said, a lot of us have the extended warranty for 8yrs…
 

Mosey

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I do as well, but the deduct is $100. Now, if this is an emissions part we are covered.
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