# P0702 output shaft revolution sensor



## Shadow_Death (Feb 21, 2016)

I'm back after pulling my hair out over this issue for some time now.

*Symptom:* It seems to be specific to me sitting still. I can drive the car down the road accelerating, holding speed, and slowing down with no issues at all.
However, if I sit at a red light then take of when it turns green there are times when it will refuse to shift out of 1st gear. I then have to pop the car into neutral shut it off and start it back up. After that it will drive fine. Also sometimes after I restart the car like that the O/D light will blink a few times then shut off and the car goes back to normal.

This problem originated around the same time as my old alternator going out. (The alternator's voltage would bounce back and forth between 12.5v and 16.5v.).

*Fixes:* I replaced the "Speed Sensor" or (output shaft revolution sensor depending on where you look it up). The problem did not go away at all. So I decided to put the old one back in thinking that the new one was just a piece of junk from Autozone. Also because I replaced the old one while the alternator had still been bouncing voltage like that thinking that maybe it was just throwing off the readings by the vehicle. Well the issue is that the problem is still there.

At this point I'm starting to wonder if I have a bad TCM because both Speed sensors work well enough that the speedometer registers the vehicles speed accurately and the needle moves according to how fast I'm going. I haven't seen any hiccups in it's movement either.

Anyone else have any ideas?

*Note:* It doesn't seem like this is a common problem because I find this issue with a lot of other vehicles.... just not Nissans.


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## rogoman (Dec 16, 2004)

If the alternator voltage is still bouncing around between 12.5 and 16.5, then you've got a problem there. At idle the voltage should HOLD STEADY somewhere between 13.2 - 15 volts. When a charging system is not charging, or overcharging, a lot of "strange" things can occur. It's not uncommon to see a multiple of stored trouble codes in the ECU memory. So, whenever a car is setting a multiple of trouble codes, idling funny or stalling, or anything out of the "norm," test the charging system before you start pulling hairs!


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## Shadow_Death (Feb 21, 2016)

rogoman said:


> If the alternator voltage is still bouncing around between 12.5 and 16.5, then you've got a problem there. At idle the voltage should HOLD STEADY somewhere between 13.2 - 15 volts. When a charging system is not charging, or overcharging, a lot of "strange" things can occur. It's not uncommon to see a multiple of stored trouble codes in the ECU memory. So, whenever a car is setting a multiple of trouble codes, idling funny or stalling, or anything out of the "norm," test the charging system before you start pulling hairs!


I have replaced the alternator and it hold steady at 15.1v. It's not ideal but it's better than the 16+ volts it was reaching. I only have 1 trouble code that comes up over and over which is the P0702 code. I did some thinking and someone also mentioned to me before that maybe the TCU failed. Tomorrow I'm going to see about removing it and having a look at it to see if my suspicions are true. A few months ago I could smell something that reminds me of burning electronics. It's a very unmistakable smell that I've experienced before back when my 99 Ranger's ECM shorted and a chip on it fried.

A little side note. My reason for thinking it may be the TCU is not only because of the smell. It's also because this problem didn't start happening until well after the last alternator went bad. I think it was right before I finally replaced it. So I'm thinking that the voltage fluctuation may have fried something in there. Does this sound possible to you or is there some sort of safeguard to prevent this from happening?


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## rogoman (Dec 16, 2004)

I would say that the 16.5 volts sure could have fried the TCU. As far as I know, there's no safeguard for the TCU. Even the constant 15.1 v shouldn't be happening; the voltage should be sitting around 13+ with a fully charged battery. I think you may have something else that's wrong like a bad ground.


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## Shadow_Death (Feb 21, 2016)

I thought about the ground issue too which is why when I replaced the old alternator I went through cleaning ground points and testing resistance. Everything tests great.

I think its just because its a reman from autozone.


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## Shadow_Death (Feb 21, 2016)

So I took out my TCM and and opened it up. I didn't find any physical damage to it. So if it is damaged then its all internal. Maybe I'm missing something when I looked at it initially so here's a bunch of pictures I took of it.














































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## darktremor (Aug 19, 2016)

There's never any physical damage for things like these. My Sentra's computer fried and there was no physical damage. Car wouldn't start though so lol no OBD and I should have known it was computer all along.

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## Shadow_Death (Feb 21, 2016)

So I decided to see if I could get my transmission to run a diagnostic as instructed in the Factory Service Manual. Wouldn't work at all.

I even thought that I would try the SES tooless diagnostic where you turn the ignition on for 3 seconds, pump the gas peddle 5 times in under 5 seconds, then wait 7 seconds, then press and hold the gas peddle for 10 seconds. I even used a watch to make sure the seconds were exact multiple times and nothing, it just refuses to do anything.


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## darktremor (Aug 19, 2016)

LOL is your computer fried or what? XD

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## Shadow_Death (Feb 21, 2016)

darktremor said:


> LOL is your computer fried or what? XD
> 
> Sent from my Moto G using Tapatalk


I've got no idea. The car runs and runs fine, but it will spaz out. I did notice that when the e-fans came on today the engine bogged. I think I'm going to look for more grounds.

So far I've cleaned the battery terminals
The one underneath the battery
The one on the transmission
The one on the engine block
and I added another ground from the alternator to the engine block

I just found another ground on the left side of the vehicle literally right to the left of the alternator pulley on the wheel well that I'm going to look at tomorrow. There has to be more grounds though.


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## darktremor (Aug 19, 2016)

Shadow_Death said:


> I've got no idea. The car runs and runs fine, but it will spaz out. I did notice that when the e-fans came on today the engine bogged. I think I'm going to look for more grounds.
> 
> So far I've cleaned the battery terminals
> The one underneath the battery
> ...


Never thought unclean grounds could cause such a bad mess.

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## Shadow_Death (Feb 21, 2016)

Wooooo! I finally found the ground problem... I think.  










The first owner put that on the car. I just noticed that it was loose..... Very loose.. So I'm going to take it apart after work and spray the wires with some safety solvent and try to clean it up and out it back together.

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## Shadow_Death (Feb 21, 2016)

Well, fixing that ground issue seemes to have fixed the engine performance but it didn't fix the transmission issue.


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## darktremor (Aug 19, 2016)

Huh, you know the wire you circled looks exactly like the one in my car. What issues did it cause you when you didnt fix it?

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## Shadow_Death (Feb 21, 2016)

Well, it was minor stuff like if I had my car in park and I rolled my windows up the engine would idle rough. If it was in park and on a slope and the car had any kind of weight on the parking gear the engine would idle rough. Stuff like that. If there was a decent electrical load the engine would idle rough. If I had to put my foot into it the car would feel under powered compared to how it should be.

The transmission problem I am having actually only happens if I'm sitting at a red light for a while. It doesn't lock me to 1st gear if I'm moving in 1st gear. However if I am sitting at a red light the car will lock me into 1st and when I take off it won't shift. But that only happens while at idle in gear at a red light. Now I have noticed that it doesn't seem to want to lock the torque converter sometimes while on the highway.


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## Shadow_Death (Feb 21, 2016)

So a friend of mine has been helping me by looking into the diagrams for the speed sensor circuit. According to his info the circuit goes as follows.

Rotation Sensor -> Gauge Cluster -> TCM

This explains why my gauges all seem to work great but still have a P0720 SES.

So this weekend I'll break out my multimeter again and check the wires from the gauge cluster to the TCU for continuity.

I am also going to order a Bluetooth reader to try and pull I to while I'm driving to see if I can dig anything up there as well. I found a BAFX reader for 21 bucks that seems to have quite a few good reviews. Will report back later on what I dig up.

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## darktremor (Aug 19, 2016)

Are you using a phone to read the codes?

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## Shadow_Death (Feb 21, 2016)

darktremor said:


> Are you using a phone to read the codes?
> 
> Sent from my Moto G using Tapatalk


I don't have it yet but I will be able to as well as get data in real time. Also it may be a coincidence but yesterday I pulled the instrument cluster to see if the wires were loose back there. Everything looked fine so I out it back and immediately got locked into 1st. I did a quick restart on the car and it drove fine this morning it did it again on my way to work so I'm starting to think that my problem is a short either in the cluster or the wiring between the cluster and the TCU.

Will more digging this week/weekend.

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## darktremor (Aug 19, 2016)

Shadow_Death said:


> I don't have it yet but I will be able to as well as get data in real time. Also it may be a coincidence but yesterday I pulled the instrument cluster to see if the wires were loose back there. Everything looked fine so I out it back and immediately got locked into 1st. I did a quick restart on the car and it drove fine this morning it did it again on my way to work so I'm starting to think that my problem is a short either in the cluster or the wiring between the cluster and the TCU.
> 
> Will more digging this week/weekend.
> 
> Sent from my Nexus 6 using Tapatalk


Didnt old Sentras always had that classic issue of Instrument Clusters going bad because of the solder connection getting loose overtime the car is used? 



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## Shadow_Death (Feb 21, 2016)

darktremor said:


> Didnt old Sentras always had that classic issue of Instrument Clusters going bad because of the solder connection getting loose overtime the car is used?
> 
> 
> Sent from my Moto G using Tapatalk


I actually have no idea, but reasons like that are why I'm digging this deep.


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## Shadow_Death (Feb 21, 2016)

At this point I suspect that I have another bad alternator. I didn't get a chance to check out the circuit board of the gauge cluster but I did do a quick voltage check on the cat and it is producing higher and higher voltage by the week. It was at 15.1 when I fixed all my ground issues. Last week it was at 15.2. Last night it was at 15.3v

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## Shadow_Death (Feb 21, 2016)

So here is what I've got so far after replacing the battery in my multimeter.









The multimeter that I am using for all of this.









The voltage with the positive lead on the alternator stud and the negative lead on the negative battery terminal.









Both leads on the respective battery terminals.

Now what I have also noticed is that when I shut the car off the voltage doesn't suddenly drop to 12.x volts at the battery. The voltage stays at 13.35 and slowly bleeds off .01v every couple of seconds.

I'm beginning to wonder if it isn't the battery itself. If I measure ohms between the alternator wire at the alternator and the battery terminal I get 0.8. My understanding is that this is too high and it should be 0.2.

All grounds slow 0L or 0.2 depending on distance.

Any ideas at all? Maybe @jdg knows?

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## Shadow_Death (Feb 21, 2016)

OK, it wouldn't let me edit my old post in mobile view so I will say it here. After letting it sit for a while my battery dropped to 12.60v with the car off.

So I did some more testing. I watched a video where this guy had shown that his car wouldn't charge if the moved the plug connected to the alternator. Not sure what it's called.

Now, that being said I decided to go look at mine for giggles. Mine doesn't have that problem. However I did notice that if I pulled that plug while the car is running that it takes aprox 30 seconds before my alternator to respond. During this time it will continue to supply 15.35v at the positive post on the alternator. After that time it will drop down to 12.18v at the battery. I decided to leave it running for a while to see just what happens. I noticed that the battery light did not come on at all and that the car stereo was still on through all this which means it should have put a drain on the battery. I can also say that the car continued to run at 12.18v so I decided to turn the headlights on and flick the brights switch to on. The voltage dropped to 12.10v then slowly rise to 12.15v where it sat. All the while the car didn't die.

Oh, another thing I noticed is that the car ran way smoother at 12.18v than with the plug connected to the alternator which would have had it producing 15.35 at the alternator's positive post. Even in reverse the car didn't shutter like it does when it gets more voltage. I think it's safe to say that my alternator is yet another POS from Autozone.


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## Shadow_Death (Feb 21, 2016)

Alright, I replaced the alternator again. I think this is good enough.  










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## darktremor (Aug 19, 2016)

Shadow_Death said:


> Alright, I replaced the alternator again. I think this is good enough.
> 
> 
> 
> ...


How much have you spent just to fix this problem? My AC cooling issue at idle ended up me having to replace alternator.

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## Shadow_Death (Feb 21, 2016)

I've spent very little trying to fix this issue. Just months and months of diagnosis then yesterday I finally just unplugged the voltage regulator for the hell of it to see what would happen. Lol

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## Shadow_Death (Feb 21, 2016)

I uploaded the wrong pic. Lol

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## Shadow_Death (Feb 21, 2016)

Swapped in a battery from another source and it charged at 13.5v

Edit: Now I just need the store I got it from to figure out that the battery is screwed and replace it.... because warranty.

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## Shadow_Death (Feb 21, 2016)

Well I officially fold. I give up on this steaming pile of crap. I've replaced this alternator twice since I've had it making it the 5th alternator that has been on it. I've fixed all the grounds that I could find. I've checked all the wires and even the battery. I am thoroughly convinced that it is the alternator and at this point with the 5th one I have little reason to think that replacing the alternator will do anything. The alternator currently installed began charging at 14.77v but over the last 2 days it has crept up to 14.89v and now 15.03v.

I've even noticed that if I took the negative ground terminal.off the battery post with it running the alternator's output will not change. At this point I just give up on fixing it.


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## darktremor (Aug 19, 2016)

Shadow_Death said:


> Well I officially fold. I give up on this steaming pile of crap. I've replaced this alternator twice since I've had it making it the 5th alternator that has been on it. I've fixed all the grounds that I could find. I've checked all the wires and even the battery. I am thoroughly convinced that it is the alternator and at this point with the 5th one I have little reason to think that replacing the alternator will do anything. The alternator currently installed began charging at 14.77v but over the last 2 days it has crept up to 14.89v and now 15.03v.
> 
> I've even noticed that if I took the negative ground terminal.off the battery post with it running the alternator's output will not change. At this point I just give up on fixing it.


While I'm no expert in electronics when it comes to cars it sounds like something in your car is frying the alternator. I know my uncles 1997 Sentra did that though I cant remember what was it that fixed this same(sort of) issue for him. Have you checked every single electrical wiring? At this point I'd take it to a mechanic

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## Shadow_Death (Feb 21, 2016)

darktremor said:


> While I'm no expert in electronics when it comes to cars it sounds like something in your car is frying the alternator. I know my uncles 1997 Sentra did that though I cant remember what was it that fixed this same(sort of) issue for him. Have you checked every single electrical wiring? At this point I'd take it to a mechanic
> 
> Sent from my Moto G using Tapatalk


I've been talking to a mechanic friend of mine as well as a few mechanic and electrical inclined friends. They're all stumped. They think I just keep getting trash alternators which I could be, but because Nissan doesn't make any new parts for 01 sentras I can't get any new alternators... Only remans.

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## darktremor (Aug 19, 2016)

Shadow_Death said:


> I've been talking to a mechanic friend of mine as well as a few mechanic and electrical inclined friends. They're all stumped. They think I just keep getting trash alternators which I could be, but because Nissan doesn't make any new parts for 01 sentras I can't get any new alternators... Only remans.
> 
> Sent from my Nexus 6 using Tapatalk


Not even RockAuto? Dont they have OEM kinda parts?

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## Shadow_Death (Feb 21, 2016)

darktremor said:


> Not even RockAuto? Dont they have OEM kinda parts?
> 
> Sent from my Moto G using Tapatalk


Oh, I don't know. I'm not willing to spend that much money if it turns out that it isn't the alternator. At this point I'm just going to wait until something stops working. >.>

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## darktremor (Aug 19, 2016)

Shadow_Death said:


> Oh, I don't know. I'm not willing to spend that much money if it turns out that it isn't the alternator. At this point I'm just going to wait until something stops working. >.>
> 
> Sent from my Nexus 6 using Tapatalk


Better prepare a backup car then, cars like ours always end up stop working at the worst time possible 

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## Shadow_Death (Feb 21, 2016)

Yup, I've got 2 diesels here that I can use when it stops working. 1 f250 and 1 f350.

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## Shadow_Death (Feb 21, 2016)

So after doing some more digging I'm starting to wonder. I saw a diagram of the charging system of the SR20 system which shows a 30a fuse on the sense line off the alternator. I can't find the damn thing. I can't find where it is, should, or would be.

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## Shadow_Death (Feb 21, 2016)

Shadow_Death said:


> So after doing some more digging I'm starting to wonder. I saw a diagram of the charging system of the SR20 system which shows a 30a fuse on the sense line off the alternator. I can't find the damn thing. I can't find where it is, should, or would be.
> 
> Sent from my Nexus 6 using Tapatalk


Even better, I just checked the Nissan GSM and it says that there is a 10a fuse at #33 that I need to check. Turns out this is under the hood and it's the horn fuse.










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## Shadow_Death (Feb 21, 2016)

It's fixed! So for anyone who may want to know. The issue was actually a combo of things. 

First off if your horn quits working and it constantly blows fuses there are threads that will tell you to just run a new horn wire from the fuse to the relay. You can do this but keep in mind that *NISSAN RAN THE ALTERNATOR SENSE WIRE (GREEN WITH A BLACK STRIPE) TO THAT HORN LINE.* This means that you will have to cut and tie that green and black wire into the new horn wire otherwise your alternator will not see the 12v current that it is looking for from the battery and it will charge at full force. In my case this was 16+ volts.

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## darktremor (Aug 19, 2016)

Well that solution was a sure anti climatic. Thought it'd be something bigger 

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## Shadow_Death (Feb 21, 2016)

darktremor said:


> Well that solution was a sure anti climatic. Thought it'd be something bigger
> 
> Sent from my Moto G using Tapatalk


Yup, so did I. Just turned out to be 1 little 20g wire.

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## Kilgrave (Jul 30, 2017)

First of all, sorry for necroing the this thread, but I have a 2003 Nissan Micra (auto transmission) with exact the same problem as Shadow_Death.

About 2 years ago it started to get stuck in 1st gear... randomly. Check Engine lights went on and codes P0702 and P0011 (if I remember correctly) were read. The only way to continue driving was to turn the car off and on again. Sometimes it would give some warning by the spedometer hovering around 40km/h despite accelerating, but not always. 

I couldn't understand what was exactly the solution and I'll be very glad if someone could explain to someone with not a lot of mechanical knowledge like me.
Thank you for your time


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## Shadow_Death (Feb 21, 2016)

Kilgrave said:


> First of all, sorry for necroing the this thread, but I have a 2003 Nissan Micra (auto transmission) with exact the same problem as Shadow_Death.
> 
> About 2 years ago it started to get stuck in 1st gear... randomly. Check Engine lights went on and codes P0702 and P0011 (if I remember correctly) were read. The only way to continue driving was to turn the car off and on again. Sometimes it would give some warning by the spedometer hovering around 40km/h despite accelerating, but not always.
> 
> ...


The answer to my problem was to jack the car up and remove the left front wheel. Between the front of that CV Joint and the back of the transaxle is a sensor with a wire going up the side to just under the air filter box. That is the sensor that caused all my issues.






This video should help with location. They aren't cheap either. I went and got mine from a salvage yard since I had plans to sell the car anyway.


Edit: A side note that was amusing to me, P0702 is a Transmission control system error and P0720 is a Output Speed Sensor Circuit Malfunction. Also your P0011 is a Intake Valve Timing Control


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## Kilgrave (Jul 30, 2017)

Thanks a lot for your quick reaction Shadow_Death. About the error, it is P0720, I made a typo in my post.

About the sensor I have already asked several salvage yards here (I live in the Nederlands) for secondhand sensors but there weren't. A new one is quite expensive as you said, around 300 euro. I'll keep looking for them then.

Thanks again


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## Shadow_Death (Feb 21, 2016)

Kilgrave said:


> Thanks a lot for your quick reaction Shadow_Death. About the error, it is P0720, I made a typo in my post.
> 
> About the sensor I have already asked several salvage yards here (I live in the Nederlands) for secondhand sensors but there weren't. A new one is quite expensive as you said, around 300 euro. I'll keep looking for them then.
> 
> Thanks again


No problem, I remember it took me about a year to realize that these cars have 2 transmission sensors. One for the Speedometer and one for the PCM. I'm glad I could help.


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## darktremor (Aug 19, 2016)

Shadow_Death said:


> No problem, I remember it took me about a year to realize that these cars have 2 transmission sensors. One for the Speedometer and one for the PCM. I'm glad I could help.


Typical Nissan's. Mine finally gave up, had to get another car.

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## Shadow_Death (Feb 21, 2016)

darktremor said:


> Typical Nissan's. Mine finally gave up, had to get another car.
> 
> Sent from my Moto G (4) using Tapatalk


Lol I sold mine. almost 200k miles on it. It was my niece's car for college. I had wrecked my 98 F150 and needed a car pretty desperately. She wanted a truck so I bought the car off her and she got a 96 Ram 1500 5.2L. Well she drove that thing for a year and decided it was too expensive for her. So I bought the truck from her and sold the Nissan. I love 2nd Gen Ram trucks. This thing is my baby now. It has 122k miles on it and mostly just cosmetic damage. It only leaks from the oil drain plug and that's a 2 dollar fix.

My little Sentra was fun but man did it get terrible MPG. It got roughly 25ish.


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## darktremor (Aug 19, 2016)

Shadow_Death said:


> Lol I sold mine. almost 200k miles on it. It was my niece's car for college. I had wrecked my 98 F150 and needed a car pretty desperately. She wanted a truck so I bought the car off her and she got a 96 Ram 1500 5.2L. Well she drove that thing for a year and decided it was too expensive for her. So I bought the truck from her and sold the Nissan. I love 2nd Gen Ram trucks. This thing is my baby now. It has 122k miles on it and mostly just cosmetic damage. It only leaks from the oil drain plug and that's a 2 dollar fix.
> 
> My little Sentra was fun but man did it get terrible MPG. It got roughly 25ish.


Nissan are worst gas hoggers than American cars themselves lol

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## rogoman (Dec 16, 2004)

darktremor said:


> Nissan are worst gas hoggers than American cars themselves lol


I'll have to differ on that. Had a Datsun 260Z that got decent MPG, a '91 Nissan 240SX that got around 26 - 28 MPG, an '09 Altima that got a best of 32 MPG and now have a '12 Altima that also gets a best of 32 MPG.


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