# Reverse problem



## Jose27093344 (3 mo ago)

Greetings, I have a 2008 Nissan Sentra, 2.0l, automatic transmission, the problem I have is that many times (Daily) after driving a little, it turned off the car and when I turn it back on, it applied reverse and it does not advance and I hear a sliding sound, at that moment I turn off the car again, turn it on again and so it applies and advances in reverse, I suppose it is an electrical problem, but where is the fault? the transmission fluid is on point, it's not lacking, nor does it smell burnt.


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## VStar650CL (Nov 12, 2020)

Sounds like either a bad brake switch or a bad shifter. Probably the switch. The gen6 Sentra (B16) has a different setup from later models, the brake pedal switch has a separate throw which is just for the shift interlock and doesn't interface with the brake lamp circuit. So you can't test just by checking the brake lamps, you need to put a test lamp on the switch wires. The fuse won't be the problem, fuse 12 feeds a whole bunch of other stuff which would be noticeable. With a test lamp connected between Green and Black, the lamp should light up dimly. If so, it proves the solenoid coil has power from the fuse and the switch ground is good, meaning the switch is faulty. If it doesn't light then go from Green to a chassis ground. If that lights dimly then the ground wire on the switch (Black) is bad. If it still doesn't light then either the shifter is bad (the coil of the solenoid is open) or there's a problem with the Green or Brown wires.


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## Jose27093344 (3 mo ago)

Ok, but I want to clarify that the car's brake lights are in perfect condition and work 100 percent, could it still be the brake switch?


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## Jose27093344 (3 mo ago)

VStar650CL said:


> Sounds like either a bad brake switch or a bad shifter. Probably the switch. The gen6 Sentra (B16) has a different setup from later models, the brake pedal switch has a separate throw which is just for the shift interlock and doesn't interface with the brake lamp circuit. So you can't test just by checking the brake lamps, you need to put a test lamp on the switch wires. The fuse won't be the problem, fuse 12 feeds a whole bunch of other stuff which would be noticeable. With a test lamp connected between Green and Black, the lamp should light up dimly. If so, it proves the solenoid coil has power from the fuse and the switch ground is good, meaning the switch is faulty. If it doesn't light then go from Green to a chassis ground. If that lights dimly then the ground wire on the switch (Black) is bad. If it still doesn't light then either the shifter is bad (the coil of the solenoid is open) or there's a problem with the Green or Brown wires.
> View attachment 9849


Ok, but I want to clarify that the car's brake lights are in perfect condition and work 100 percent, could it still be the brake switch?


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## VStar650CL (Nov 12, 2020)

Jose27093344 said:


> Ok, but I want to clarify that the car's brake lights are in perfect condition and work 100 percent, could it still be the brake switch?


There are two "throws" on your brake switch, pins 1~2 for the brake lamps and 3~4 for the shift solenoid. They're completely separate electrically. That's why I said you _can't_ check by way of the brake lamps, because it's entirely possible (and likely, in this case) for the contacts in one throw to go bad while the other throw still works properly. Check it the way I advised and you'll know exactly what the problem is.


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## Jose27093344 (3 mo ago)

VStar650CL said:


> There are two "throws" on your brake switch, pins 1~2 for the brake lamps and 3~4 for the shift solenoid. They're completely separate electrically. That's why I said you _can't_ check by way of the brake lamps, because it's entirely possible (and likely, in this case) for the contacts in one throw to go bad while the other throw still works properly. Check it the way I advised and you'll know exactly what the problem is.


Yes, I understood it, then I read your advice several times, so that can cause that sliding sound? that when you turn it off and on again it magically disappears?


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## VStar650CL (Nov 12, 2020)

Your noise is most likely from the solenoid trying to engage but not getting there because of high resistance in the switch contacts. Healthy circuits just make a single "click", but resistance causes low voltage across the coil and the solenoid will chatter. It typically only takes about 8 ohms across the switch contacts to make a Nissan shifter misbehave.


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## Jose27093344 (3 mo ago)

VStar650CL said:


> Your noise is most likely from the solenoid trying to engage but not getting there because of high resistance in the switch contacts. Healthy circuits just make a single "click", but resistance causes low voltage across the coil and the solenoid will chatter. It typically only takes about 8 ohms across the switch contacts to make a Nissan shifter misbehave.


The truth is that I did not know the function of this switch, thanks to your masterful opinion I began to read a little more, and what I get on the internet is that when this switch is damaged it does not let the car leave the parking lot, I will trust that it also causes the problem that my vehicle has.


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## VStar650CL (Nov 12, 2020)

They're cheap and it's a no-tools operation to replace it, so even if you want to throw parts at it instead of doing diagnosis, it will be the first the first thing to try. You can get a Beck-Arnley replacement from RockAuto for $17.


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## Jose27093344 (3 mo ago)

VStar650CL said:


> Son baratos y es una operación sin herramientas para reemplazarlo, por lo que incluso si desea arrojarle piezas en lugar de hacer un diagnóstico, será lo primero que intente. Puede obtener un reemplazo de Beck-Arnley de RockAuto por $17.
> [/COTIZAR]
> Casualmente ya compre la pieza, mañana iré a reemplazarla, hay posibilidad de que el problema sea por el sensor de rango? me aconsejas cambiarlo tambien?


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## VStar650CL (Nov 12, 2020)

Jose27093344 said:


> Casualmente ya compre la pieza, mañana iré a reemplazarla, hay posibilidad de que el problema sea por el sensor de rango? me aconsejas cambiarlo tambien?


It's remotely possible, but I doubt it. Since I started at my present dealership in 2013, I've seen exactly 1 bad Range Switch. They use "ball and spring" contacts which are very durable and hardly ever fail. On the other hand, Nissan brake pedal switches are very prone to failure and we replace them all the time.


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## Jose27093344 (3 mo ago)

VStar650CL said:


> It's remotely possible, but I doubt it. Since I started at my present dealership in 2013, I've seen exactly 1 bad Range Switch. They use "ball and spring" contacts which are very durable and hardly ever fail. On the other hand, Nissan brake pedal switches are very prone to failure and we replace them all the time.





VStar650CL said:


> It's remotely possible, but I doubt it. Since I started at my present dealership in 2013, I've seen exactly 1 bad Range Switch. They use "ball and spring" contacts which are very durable and hardly ever fail. On the other hand, Nissan brake pedal switches are very prone to failure and we replace them all the time.


good afternoon my friend, I have already changed the piece, and the truth is that I have done some tests, I have been in the street and I have applied reverse several times and I have not had any problem, but the sliding sound is still felt, I am going to attach a couple of videos so you have a better idea of the sound. the sound is felt even in parking and in neutral. however the car develops good speed and displacement


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## Jose27093344 (3 mo ago)

Jose27093344 said:


> good afternoon my friend, I have already changed the piece, and the truth is that I have done some tests, I have been in the street and I have applied reverse several times and I have not had any problem, but the sliding sound is still felt, I am going to attach a couple of videos so you have a better idea of the sound. the sound is felt even in parking and in neutral. however the car develops good speed and displacement


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## Jose27093344 (3 mo ago)

VStar650CL said:


> It's remotely possible, but I doubt it. Since I started at my present dealership in 2013, I've seen exactly 1 bad Range Switch. They use "ball and spring" contacts which are very durable and hardly ever fail. On the other hand, Nissan brake pedal switches are very prone to failure and we replace them all the time.












Adjunt sound sliding videos.


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## VStar650CL (Nov 12, 2020)

Sounds like the alternator. Could be the alternator itself, or there's also an overrunning clutch built into the alternator pulley which makes a similar whine.


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## Jose27093344 (3 mo ago)

VStar650CL said:


> Sounds like the alternator. Could be the alternator itself, or there's also an overrunning clutch built into the alternator pulley which makes a similar whine.


Does the alternator or malfunction of its pulley or bearing have something to do with the transmission?


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## VStar650CL (Nov 12, 2020)

Nope. I think you have two separate issues.


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## Jose27093344 (3 mo ago)

do i need to replace the tcm if i replace the transmission on my nissan?


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## VStar650CL (Nov 12, 2020)

With a used CVT, it's best to get the donor TCM along with the donor tranny. The donor TCM already has the correct calibration factors for that car's Valve Body, so it saves a lot of programming which usually needs to be done by a dealer.


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