Assistance With P0717, P0796 & U0402

[TinoTheGreek]

Hello there!

I have a 2017 Honda Civic EX Sedan with the 2.0L K20C2.

Vehicle recently went into limp mode and shows P0717 (CVT Input Shaft (Drive Pulley) Speed Sensor Circuit No Signal Input) as a permanent code as well as a P0796 (Pressure Control Solenoid "C" Performance/Stuck Off) and a U0402 (Invalid Data Received From TCM)

Tested all wires (the ones that go to the TCM connector anyway) from all 4 of the sensors on the transmission for continuity and they were okay.
Tested all 3 of the grounds on the transmission harness for continuity as well and they were also okay.

Tested the transmission grounds from the transmission harness to the engine harness ground for continuity and they were okay.

Already went ahead and replaced the CVT Drive Pulley Speed Sensor (28810-5DJ-004) and no luck.

I've seen others with the same issues and instead of replacing the sensor I replaced, they replaced the sensor next to it which is the Torque Converter Turbine Speed Sensor (28820-RJ2-003) in order to fix the problem. But before I go buying another sensor I'd like to try and diagnose first.

Does anyone know which wire on the sensor connector is the signal wire? I'd like to test that since the code is for no signal.

Also, any input would be appreciated.

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[itbedave]

I'm running into a similar problem with my 2017 EX hatchback 1.4L. I just replaced that lower sensor and still showing no signal in the circuit.

 

[TinoTheGreek]

I'm running into a similar problem with my 2017 EX hatchback 1.4L. I just replaced that lower sensor and still showing no signal in the circuit.

I just resolved my issue this morning.

I took some time to diagnose the issue. Even though I was getting a P0717 (CVT Input Shaft (Drive Pulley) Speed Sensor Circuit No Signal Input) the issue was in fact NOT the Drive Pulley Speed Sensor.

Instead, after probing the connectors of all the speed sensors and testing with the multimeter, it turns out the sensor that was two inches away from the Drive Pulley Speed Sensor, the Torque Converter Turbine Speed Sensor, was the one that failed.

I would suggest checking live data of each speed sensor if you have access to it before just replacing sensors. If not, try using a multimeter the way I did.

Hope this helps.

 

[itbedave]

Thanks for the tip! I'm going to check that with my multimeter.

Do you have a part number for that sensor? And I assume that replacing it cured your problem?

 

[itbedave]

Just want to be certain that the sensor with the red arrow is the one you're talking about? I've replaced the one with the green arrow already. Thanks!

 

[TinoTheGreek]

Just want to be certain that the sensor with the red arrow is the one you're talking about? I've replaced the one with the green arrow already. Thanks!

I don't have the same CVT as you do, but after looking at some parts diagrams for your build the one with the red arrow is a pressure sensor. You don't have to replace that. The sensor under it with the green arrow is the Drive Pulley Speed Sensor. I changed that on my CVT as well and the issue didn't go away either. I replaced the Torque Converter Turbine Speed Sensor to fix the issue. Your transmission seems to be separated into 3 sections. Let me get some diagrams in here.

Section 1 (Closest To The Engine)
Section 2 (Middle Piece)
Section 3 (Farthest From The Engine)

Now, please keep in mind that your transmission has 2 different Drive Pulley Speed Sensors. Make sure to check BOTH of them. You already replaced the one from the third section. Check the one in the first section and then check the Torque Converter Turbine Speed Sensor that's in the second section. I added all the part numbers to the diagrams if you need em. Let me know if you get it sorted out and what you did to fix it.

 

[itbedave]

I don't have the same CVT as you do, but after looking at some parts diagrams for your build the one with the red arrow is a pressure sensor. You don't have to replace that. The sensor under it with the green arrow is the Drive Pulley Speed Sensor. I changed that on my CVT as well and the issue didn't go away either. I replaced the Torque Converter Turbine Speed Sensor to fix the issue. Your transmission seems to be separated into 3 sections. Let me get some diagrams in here.

Section 1 (Closest To The Engine)
Section 2 (Middle Piece)
Section 3 (Farthest From The Engine)

Now, please keep in mind that your transmission has 2 different Drive Pulley Speed Sensors. Make sure to check BOTH of them. You already replaced the one from the third section. Check the one in the first section and then check the Torque Converter Turbine Speed Sensor that's in the second section. I added all the part numbers to the diagrams if you need em. Let me know if you get it sorted out and what you did to fix it.

Thanks so much for the clarification and the diagrams! I was able to get the pressure sensor for $13... So no biggie. But no, it didn't change the problem. This is the code I'm still getting (photo)

I will get into again tomorrow and locate and test those 2 other sensors and report back. Thanks much!

 

[itbedave]

I would suggest checking live data of each speed sensor if you have access to it before just replacing sensors. If not, try using a multimeter the way I did.

I realized... I may not even be testing the sensors right. Better to ask for help than to assume I am doing it right. Do you have quick tips on the proper way or a link to a YouTube video explaining how with these 3 pin sensors? I appreciate it and maybe it will help someone else in the future as well.

 

[itbedave]

I don't have the same CVT as you do, but after looking at some parts diagrams for your build the one with the red arrow is a pressure sensor. You don't have to replace that. The sensor under it with the green arrow is the Drive Pulley Speed Sensor. I changed that on my CVT as well and the issue didn't go away either. I replaced the Torque Converter Turbine Speed Sensor to fix the issue. Your transmission seems to be separated into 3 sections. Let me get some diagrams in here.

Section 1 (Closest To The Engine)
Section 2 (Middle Piece)
Section 3 (Farthest From The Engine)

Now, please keep in mind that your transmission has 2 different Drive Pulley Speed Sensors. Make sure to check BOTH of them. You already replaced the one from the third section. Check the one in the first section and then check the Torque Converter Turbine Speed Sensor that's in the second section. I added all the part numbers to the diagrams if you need em. Let me know if you get it sorted out and what you did to fix it.

DUDE!!! Finally got those 2 sensors you suggested replaced today... Didn't even test them as it was just easier to replace them... AND IT'S FIXED!!! ALL CODES ARE GONE AND IT'S RUNNING FINE!

THANK YOU SOOOO MUCH!!!

I feel like I owe you some beer or something because NO ONE had this solution anywhere... Nothing on YouTube... On any other forums I could find... Not even the Honda specialist I took it too could figure out what was going on. (And he wants to know if I fix it, what I had to do! Maybe I should ask him for my money back and I'll tell him? )

Message me if you would... I want to thank you properly for your assistance here!

 

[TinoTheGreek]

DUDE!!! Finally got those 2 sensors you suggested replaced today... Didn't even test them as it was just easier to replace them... AND IT'S FIXED!!! ALL CODES ARE GONE AND IT'S RUNNING FINE!

THANK YOU SOOOO MUCH!!!

I feel like I owe you some beer or something because NO ONE had this solution anywhere... Nothing on YouTube... On any other forums I could find... Not even the Honda specialist I took it too could figure out what was going on. (And he wants to know if I fix it, what I had to do! Maybe I should ask him for my money back and I'll tell him? )

Message me if you would... I want to thank you properly for your assistance here!

Sorry for the late response, I'm glad you figured it out tho and glad I could help! when I looked online I couldn't find ANYTHING regarding this issue.

I do my own mechanic work unless it's something that I'm not capable of doing and I almost gave up on this, mainly because it's my daily and didn't have time to sit down and diagnose the issue properly. Almost put in an appointment for the dealership but I ended up watching some videos that weren't in english and I stumbled upon this here. After watching it I came to the conclusion that even if you get a drive pulley sensor code it may not be the sensor the code is calling for.

Looks like he diagnoses the issue on camera as well, just yanno, not in english.

He wants to know what you had to do? Ha! if he's a so called specialist he should know how to do a proper diagnosis.

No worries man, I appreciate it! I'm not in the US anyway so I wouldn't be able to take you up on that lol

 

[itbedave]

Sorry for the late response, I'm glad you figured it out tho and glad I could help! when I looked online I couldn't find ANYTHING regarding this issue.

I do my own mechanic work unless it's something that I'm not capable of doing and I almost gave up on this, mainly because it's my daily and didn't have time to sit down and diagnose the issue properly. Almost put in an appointment for the dealership but I ended up watching some videos that weren't in english and I stumbled upon this here. After watching it I came to the conclusion that even if you get a drive pulley sensor code it may not be the sensor the code is calling for.

Looks like he diagnoses the issue on camera as well, just yanno, not in english.

He wants to know what you had to do? Ha! if he's a so called specialist he should know how to do a proper diagnosis.

No worries man, I appreciate it! I'm not in the US anyway so I wouldn't be able to take you up on that lol

Well.... It WAS fine. Today I tried to get up to highway speed, and it acted like it wouldn't shift up. Revved up to 4000rpm but wouldn't shift. Couldn't get much above 55mph. Yesterday, no issues getting it up over 70 on the highway.

Also was slow to get moving from stopped. But, no lights and not even stored codes???

I've pulled the battery cable and the ECU and TCU fuses for awhile. Going to put those back and see if it helps do some kind of reset to the system. Fingers are still crossed!

 

[TinoTheGreek]

Well.... It WAS fine. Today I tried to get up to highway speed, and it acted like it wouldn't shift up. Revved up to 4000rpm but wouldn't shift. Couldn't get much above 55mph. Yesterday, no issues getting it up over 70 on the highway.

Also was slow to get moving from stopped. But, no lights and not even stored codes???

I've pulled the battery cable and the ECU and TCU fuses for awhile. Going to put those back and see if it helps do some kind of reset to the system. Fingers are still crossed!

Oh wow, I didn't have any issues after replacing the sensor. I did clear all the codes before going on a drive though.

Yeah, reset the whole system, drive it for a few miles and see if it still acts funny. There may be some stored faults causing issues. If the issue still persists, worst case you may have internal damage. Unlikely though.

If you have time, remove the sensors and give em a wipe, sometimes they have a good amount of buildup on them and it can cause issues. Also, make sure to check that all the sensors are seated properly.

 

[itbedave]

I initially had also gotten the P0796 code for transmission solenoid C off/stuck... But I didn't get it again after I cleared the codes. Only the P0793.

When I took it to the local Honda specialist, he got the P0796 code again, but couldn't find any info about replacing the solenoids, nor the parts to do so. He cleared the codes and only P0793 came back, as usual.

So after I replaced the 2 sensors you suggested, and cleared codes, I'm still getting NO codes and no pending or permanent codes!

I drove it 150 miles yesterday on the highway and still... No codes. It definitely doesn't shift right... But the longer I drove it, the more I figured out that I could ease on/off the accelerator if the RPMs surged when the trans slipped, and get it to go into higher gear. And it would stay there quite awhile if I was careful and didn't try to accelerate too quickly. But inevitably, it would slip again and I'd have to back off then accelerate slowly again. I was getting it up over 70mph regularly without too many issues. But when I stopped, it wouldn't drop back into first. It was like was starting in 2nd or 3rd gear every time.

So, my daughter's boyfriend is a mechanic but didn't know too much about Hondas. But he thinks that solenoid may still be sticking. But it's confused by the lack of any codes. The CVT fluid was drained and changed by the previous Honda mechanic, but I'm unsure if he changed any filters at that time? I'm checking that out today.

What I can't find is hardly any info about replaceing those solenoids... How to find parts, cost and difficulty of doing so, etc. I found a Honda Dealership website talking about that they do that... So it's possible. Just can't find much info outside of that... Not even here in this forum. So I'm in the process of posting a new thread about it and will link to this post since I'm sure I can't be the only one who's run into this problem. I hope it all helps someone else in the future.

Thanks again for your assistance and feedback! Would be interested in any further thoughts or insight you might have as well!

 

[TinoTheGreek]

I initially had also gotten the P0796 code for transmission solenoid C off/stuck... But I didn't get it again after I cleared the codes. Only the P0793.

When I took it to the local Honda specialist, he got the P0796 code again, but couldn't find any info about replacing the solenoids, nor the parts to do so. He cleared the codes and only P0793 came back, as usual.

So after I replaced the 2 sensors you suggested, and cleared codes, I'm still getting NO codes and no pending or permanent codes!

I drove it 150 miles yesterday on the highway and still... No codes. It definitely doesn't shift right... But the longer I drove it, the more I figured out that I could ease on/off the accelerator if the RPMs surged when the trans slipped, and get it to go into higher gear. And it would stay there quite awhile if I was careful and didn't try to accelerate too quickly. But inevitably, it would slip again and I'd have to back off then accelerate slowly again. I was getting it up over 70mph regularly without too many issues. But when I stopped, it wouldn't drop back into first. It was like was starting in 2nd or 3rd gear every time.

So, my daughter's boyfriend is a mechanic but didn't know too much about Hondas. But he thinks that solenoid may still be sticking. But it's confused by the lack of any codes. The CVT fluid was drained and changed by the previous Honda mechanic, but I'm unsure if he changed any filters at that time? I'm checking that out today.

What I can't find is hardly any info about replaceing those solenoids... How to find parts, cost and difficulty of doing so, etc. I found a Honda Dealership website talking about that they do that... So it's possible. Just can't find much info outside of that... Not even here in this forum. So I'm in the process of posting a new thread about it and will link to this post since I'm sure I can't be the only one who's run into this problem. I hope it all helps someone else in the future.

Thanks again for your assistance and feedback! Would be interested in any further thoughts or insight you might have as well!

Hmm, I see.

Well, I also had the code P0796 for 'Solenoid C' but in my case I believe it was just a side effect of the bad sensor. You said the trans was serviced recently? Was the correct amount of fluid added back in? Also, what fluid did they use? You don't want to use anything other than the CVT Fluid Honda sells which is HCF-2 CVT FLuid Part Number (08200-HFC2)

Honestly, this sounds like a case of low fluid.

There are two (2) filters for the transmission:
One is a strainer located inside the trans, which would require dropping the trans fluid pan under the trans. Part Number (25420-5LJ-003). If you're going to replace that you'll have to replace the gasket for the lower pan as well. Part Number (21814-RJ2-003).

The other is a cylindrical cartridge type filter that slots into the front side of the transmission (sideways orientation) which is located behind the warmer/cooler. Part Number (25450-P4V-013) & The O-Ring For it Part Number (91305-PN4-003). If you plan on replacing that filter too then you should probably replace the O-rings for the warmer/cooler as well as you don't want to reassemble and it starts to leak. Part Numbers (25564-5LJ-A01) & (25565-5LJ-A01).

Now, the solenoid itself, I don't know why but I can't find the part number for Solenoid C on the Honda parts website I use. I can only find the part number for Solenoid A. I did some research online though and I am seeing Part Number (28500-P6H-013) referenced multiple times on different posts as the part number for Solenoid C which is supposed to have a brown connector on it. But I don't suggest just buying parts at this point.

First, make sure the vehicle is on level ground, and the vehicle itself is level. Then, check the fluid level by opening the check bolt. If you have a small stream of liquid coming out then it's good. If not then fill it till it starts coming out the hole slowly then put the bolt back. From what I've seen online this is the correct procedure, and it's the one I follow as well when servicing my CVT. I see some people just put the whole Five (5) bottles in when they service the trans but I don't think overfilling the trans is a good thing.

If that doesn't make a difference or it was already filled properly, you'll have to drop the pan, remove the strainer and remove Solenoid C to have it tested. If you're going to be in there might as well replace the strainer for good measure.

There is a chance that a reflash of the ECU & TCM would help, sometimes it's a software issue. You'd have to take it to the dealership for that though, and they'll probably charge about $200-$300. I wouldn't suggest that until you're out of options.

I'm hoping there isn't any internal damage. Hope this helps!

 

[itbedave]

I don't believe either trans filter was replaced. It's not listed as a part on the invoice at least.

I will check the fluid level though and let you know what I find.

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