Jerk when gradually slowing down

[Altima19]

Hi everyone!

I'm trying to figure it out for a long time, but now I'm feeling like I need help.

I've got 2019 Altima 2.5 S, FWD. It was originally bought in California with 59 000 miles on it.

While gradually slowing down without using brakes or with a slight force on the brake pedal while reaching the speed about 15-17MPH I'm getting a noticeable jerk. It's the moment like when the transmission engage/disengage a clutch or something. It's sometimes not a light jerk, but strong enough so I can even hear "click" sound from my front left wheel (this sound is a known Nissan's issue, I know that and I even fixed it two years ago and now it's coming back again). It usually happens when the car is hot, especially after some hard city traffic with constantly stop n go. When It's cold I don't remember that I can feel it. At all other cases CVT works great.
I started to feel this issue about 70 000 miles ago. Now I have 133000 miles. The issue does not seems like having any progress, it stays the same. But it just so annoying every time trying to find the right moment to release a brake for a second when it's going to jerk, because this way it's not so strong.

About the maintenance.
1) Transmission.
a) First CVT Fluid changing was at 70000 miles. I drained it once, then drove about 50 miles, drain it one more time and replaced both filters. All parts and the NS3 fluid were OEM from the Nissan dealer.
b) Next fluid changing was at 100 000 miles. Drained the OEM fluid only, without filters.
c) Next fluid changing was at 110 000 miles with both OEM filters. All parts were from Nissan dealer.
d) Last time I changed fluid at 120 000 miles - just drained it without replacing filters, same Nissan OEM NS3 fluid from the Nissan dealer.

2) At 110 000 miles replaced spark plugs with the ignition coils. Spark plugs were Denso - same model as in OEM (FK20HR11), ordered from Denso website. Ignition coils were OEM from Nissan dealer.

3) As for the throttle body, it was cleaned 2 times for now after I got the Christmas tree on my dashboard with the P0101 error code. But before clean it, I tried to clean the MAF sensor with CRC MAF cleaner. This was not helpful. I tried to buy a new OEM MAF sensor, I didn't help as well. Then I found that I need to clean a throttle body and it worked.

4) Air and Oil filters were always OEM from the Nissan dealer. Before 80 000 miles engine oil was Mobil 1 0w20 Fuel Economy then I switched to Mobil 1 0w20 High Mileage. There's still no oil burning problem. Engine oil changing interval - 5000-6000 miles.

5) PCV (Nissan OEM from dealer) valve replaced at 110 000 miles.

6) Battery was replaced at about 80 000 miles. That time I decided to use conventional battery (Not AGM or EFB) from Walmart - Everstart Maxx-H5, 650CCA. It was on November 2022. Even it works well, now I'm not sure if it was the right decision, because the original battery was EFB for some reason. But that time I thought that if my car doesn't have Start/Stop, then why should I buy AGM or EFB and overpay for it. Even the Walmart were offering AGM only batteries for 2019 Altima on their website.
Was an EFB battery were there for a reason? Can it be a reason of that "jerk" problem?

7) I didn't update ECM/TCM.

Yesterday I tried to relearn throttle body using Launch X431 Pro scanner. It didn't help.
But I'm going to try to turn off the "engine braking" function in transmission using this scanner, some people says it could help.

Also I'm going to pull fuel injectors to check if some of them leaks and if not, then will clean them along with the intake valves. I have ordered some gaskets from a dealer for the throttle body, intake manifold and injectors.

What do you guys think? All inputs will be highly appreciated.

[Altima19]

One more thing about the possible battery/charging problem.
I'm using the voltmeter in the cigarette charger under the dashboard and sometimes it shows 11.7 volts. One time I saw 12 volts right when I was slowing down before the traffic light.
Even though when the car is idling it shows 13-14.5, I'm having a little concern about that 11.7 volts.

[VStar650CL]

That alternator has an overrunning clutch built into the pulley, and the Altima clutches are infamous for bad noises and untimely death. If you're only seeing the low voltages on decel, it's a good bet the clutch is spinning too free and momentarily killing your output. If it's happening all the time then the likely culprit is your Battery Current Sensor (located on the ground cable).

The transmission problem sounds like you're feeling the lockup clutch let go in the Torque Converter. then getting some surge as the TCM drops the gear ratio. Many of them do that in their old age (my wife's '13 is one of them). There may be nothing you can do about it. It probably doesn't help if your axles have enough play to do the clickety thing.

[Altima19]

That alternator has an overrunning clutch built into the pulley, and the Altima clutches are infamous for bad noises and untimely death. If you're only seeing the low voltages on decel, it's a good bet the clutch is spinning too free and momentarily killing your output. If it's happening all the time then the likely culprit is your Battery Current Sensor (located on the ground cable).

The transmission problem sounds like you're feeling the lockup clutch let go in the Torque Converter. then getting some surge as the TCM drops the gear ratio. Many of them do that in their old age (my wife's '13 is one of them). There may be nothing you can do about it. It probably doesn't help if your axles have enough play to do the clickety thing.

Thank you for the reply, I appreciate it.

As for the voltage. I saw 11.7v few times. But actually not only on decel. Sometimes in different conditions. When I cruising at 80mph on a highway, I usually see 12.7v. But when I start the car in the morning, it shows 14v+.
The question here is it normal to have sometimes 11.7v and the most of the time 12.7v?

As for the transmission. Do you think it’s nothing to do with the ECM/TCM software update, or injectors cleaning, or intake valves cleaning?
Also I have some doubts about the cvt fluid level. Do you know at which temperature should I open the overflow bolt to check the level? I was checking the level at 95-113F. Is that correct temperature?

[VStar650CL]

Voltage of 11.7V is never normal. The car does have "smart" charging and starting out at 14V and gradually tapering off to 12-and-change is normal. Make sure your battery ground connections are super clean, crud can throw off the current sensor readings and screw up the smartwork. If you still get occasional episodes below 12V, try a new current sensor.

There haven't been a whole lot of revs to the ECM/TCM firmware on the gen6's, and in any case firmware doesn't change over time, conditions do. So I rather doubt it's a pure firmware issue (although checking and updating is never a bad thing).

Nissan throttle bodies are somewhat carbon-prone, so cleaning it and doing an IAVL wouldn't hurt. Vis the injectors, throw some SeaFoam in the tank. Nissan injectors are in general very reliable, but of course fuel may not be.

The transmission needs to be 104F or higher to use the leveling plug.

[Altima19]

Voltage of 11.7V is never normal. The car does have "smart" charging and starting out at 14V and gradually tapering off to 12-and-change is normal. Make sure your battery ground connections are super clean, crud can throw off the current sensor readings and screw up the smartwork. If you still get occasional episodes below 12V, try a new current sensor.

There haven't been a whole lot of revs to the ECM/TCM firmware on the gen6's, and in any case firmware doesn't change over time, conditions do. So I rather doubt it's a pure firmware issue (although checking and updating is never a bad thing).

Nissan throttle bodies are somewhat carbon-prone, so cleaning it and doing an IAVL wouldn't hurt. Vis the injectors, throw some SeaFoam in the tank. Nissan injectors are in general very reliable, but of course fuel may not be.

The transmission needs to be 104F or higher to use the leveling plug.

Thank you for the quick reply!

As for the alternator I see, will check the ground connections, thank you.

Do you think that the regular acid battery (non agm or non efb) can cause any problems for electrical system? Or as long the battery can start the car, then it should be good?

Throttle body. What is the IAVL? And how to do it properly on 6th gen without Consult?
I cleaned the throttle body last week. But I could not complete the learning procedure from this video: https://youtu.be/hUlGxqylpCs?si=CMpz-q_mm78232JH
I tried 6 times using the stopwatch, but no luck.
But it’s idling good, nothing changed after cleaning.

Intake valves. What result could I get if I clean the valves?
Is it about the fuel economy? Currently at 133 000 miles I still have the same mpg as when it was 59000 miles.

transmission. So I can check the level at 104F and higher. “Higher” means literally any temperature, even 160F?
And when should I put the leveling plug back? When it completely stopped dripping, or when it still slowly dripping?

[VStar650CL]

The charging system shouldn't have any problems with a regular flooded battery.

IAVL = Idle Air Volume Learn. If you have CVTz50 to monitor the transmission, it has IAVL in work support for the engine. Trying to do it with the manual method on an I-key vehicle can be an exercise in hair-pulling and futility.

The gen6 Altie engines don't generally have problems with carbon on the valves because they have both port and DGI injection. I wouldn't worry about it.

Yes, anything above 104F. We've found that when the stream "hiccups" and goes from a strong to a weak stream, that gives us the most correct reading on the test stick. But you can let it run all the way down to a dribble, slightly underfilled will never hurt you. Overfilling is the thing to avoid.

[Altima19]

The charging system shouldn't have any problems with a regular flooded battery.

IAVL = Idle Air Volume Learn. If you have CVTz50 to monitor the transmission, it has IAVL in work support for the engine. Trying to do it with the manual method on an I-key vehicle can be an exercise in hair-pulling and futility.

The gen6 Altie engines don't generally have problems with carbon on the valves because they have both port and DGI injection. I wouldn't worry about it.

Yes, anything above 104F. We've found that when the stream "hiccups" and goes from a strong to a weak stream, that gives us the most correct reading on the test stick. But you can let it run all the way down to a dribble, slightly underfilled will never hurt you. Overfilling is the thing to avoid.

Thank you! Will try to check the level one more time and do an IAVL.

Will let you know results.

[Altima19]

The charging system shouldn't have any problems with a regular flooded battery.

IAVL = Idle Air Volume Learn. If you have CVTz50 to monitor the transmission, it has IAVL in work support for the engine. Trying to do it with the manual method on an I-key vehicle can be an exercise in hair-pulling and futility.

The gen6 Altie engines don't generally have problems with carbon on the valves because they have both port and DGI injection. I wouldn't worry about it.

Yes, anything above 104F. We've found that when the stream "hiccups" and goes from a strong to a weak stream, that gives us the most correct reading on the test stick. But you can let it run all the way down to a dribble, slightly underfilled will never hurt you. Overfilling is the thing to avoid.

I did the IAVL using Launch x431 scanner, it had been completed successfully.

Checked the CVT fluid level. It was overfilled a little. I drained out about 100-150ml. Draining started at 114F and I finished it few moments before the dribble comes.

Drained fluid screenshot: https://drive.google.com/file/d/19H0ygY ... drive_link

I can’t say that the jerk totally disappeared during my 20 miles test drive. It’s still there, but became kind of lighter, not so hard as it was.

As for the battery ground wire. I found it. It looks good to me. Please take a look:

Ground wire screenshots:
https://drive.google.com/file/d/1kL_j8l ... drive_link
https://drive.google.com/file/d/1pA9lEi ... drive_link
https://drive.google.com/file/d/1M39waD ... drive_link
https://drive.google.com/file/d/1XuJxRZ ... sp=sharing

What do you think?

Also, while driving those 20 miles around the town, there was few moments with less than 12v voltage. One of them lasted about 1 minute when I was driving about 20-25 mph in community speed limit.

Voltage screenshot: https://drive.google.com/file/d/1ddN0mQ ... sp=sharing

[D1dad]

Vstar can correct me if I’m wrong, but I believe the cvt temp for leveling is 95-113. I always drain at 105. 114 would make the cvt slightly underfilled, although probably not enough to matter. My 18 rogue has been done a dozen times in 90k and I’ve never had an issue leveling off at that temp. As far as the battery goes on the newer altimas, I’d have stuck with the agm. Nissan used it for a reason, what reason? Who the hell knows.

[VStar650CL]

Vstar can correct me if I’m wrong, but I believe the cvt temp for leveling is 95-113.

As usual, Nissan has conflicting information in the manual. When using the special-tool check stick they specify a temperature of 170~180F, when using the plug and charge pipe they specify 95~113F and (quote) "approximately 104F". It's actually pretty hard to get anything above 130F in the garage without doing a TC stall to artificially drive it up, so we just use 104F or higher. "Or higher" usually amounts to under 130F, and doing it at too high a temperature will simply result in a harmless underfill and not a destructive overfill. Keep in mind that none of them are fussy about underfilling within reason. So if you need to err when using the leveling plug, err warm.

[Altima19]

Vstar can correct me if I’m wrong, but I believe the cvt temp for leveling is 95-113. I always drain at 105. 114 would make the cvt slightly underfilled, although probably not enough to matter. My 18 rogue has been done a dozen times in 90k and I’ve never had an issue leveling off at that temp. As far as the battery goes on the newer altimas, I’d have stuck with the agm. Nissan used it for a reason, what reason? Who the hell knows.

Thank you for your input, I appreciate it.

During all my cvt fluid changes I used 95-114F temperature for leveling as well. It didn’t make any problems for me. But this time I tried to adjust the level as I mentioned earlier, nothing has been changed. I found same jerks while driving last couple of days.

[Altima19]

As I mentioned before, I was occasionally experiencing low voltage problem, when I falls to 11.5-11.8V.

Today I disconnected the Battery Current Sensor from the battery ground wire and my voltage became much better. See the screenshot of cvtz50 below.

https://drive.google.com/file/d/1FjOlDH ... p=drivesdk

[VStar650CL]

Today I disconnected the Battery Current Sensor from the battery ground wire and my voltage became much better. See the screenshot of cvtz50 below.

https://drive.google.com/file/d/1FjOlDH ... p=drivesdk

Sigh. Another "smart charging system" acting stupid.

The ECM will throw a P155x code for the open sensor, but it won't light the MIL. So if you want to leave the sensor disconnected and ignore the code, there's nothing wrong with that. Just do a voltage drop test on your engine ground and make sure the problem isn't being induced by a bad cable.
keep-your-engine-on-the-ground-not-just ... 28130.html

[Altima19]

Today I disconnected the Battery Current Sensor from the battery ground wire and my voltage became much better. See the screenshot of cvtz50 below.

https://drive.google.com/file/d/1FjOlDH ... p=drivesdk

Sigh. Another "smart charging system" acting stupid.

The ECM will throw a P155x code for the open sensor, but it won't light the MIL. So if you want to leave the sensor disconnected and ignore the code, there's nothing wrong with that. Just do a voltage drop test on your engine ground and make sure the problem isn't being induced by a bad cable.
keep-your-engine-on-the-ground-not-just ... 28130.html

Thank you for the great post! Never heard about that problem before.

I bought a multimeter to run the test. But I could find only 1 spot that needs to be checked - ground wire from the battery to the body which holds by 2 bolts. There was nothing wrong with the Vdrop there.
By any chance, do you have any scheme where I can find those spots that needs to be checked?

[VStar650CL]

Like it says in the post, you can check the overall integrity just by measuring from the negative post to the block and chassis. Anyplace on the block and anyplace on the chassis is good, and if both test okay then no further checks are needed. Only if they're high do you need to start working your way down the cable to find the resistance. The mid-cable chassis lug on Altimas and Maxes is a particular PITA, the screw is directly underneath the battery tray and can only be accessed either from underneath or by removing the battery and tray.

[Altima19]

Like it says in the post, you can check the overall integrity just by measuring from the negative post to the block and chassis. Anyplace on the block and anyplace on the chassis is good, and if both test okay then no further checks are needed. Only if they're high do you need to start working your way down the cable to find the resistance. The mid-cable chassis lug on Altimas and Maxes is a particular PITA, the screw is directly underneath the battery tray and can only be accessed either from underneath or by removing the battery and tray.

Just did it. Checked engine, transmission, alternator and throttle body. Everywhere except of the throttle body I saw 1.7-1.8mV. But throttle body showed 35mV before I start the car. Then I started the car, then I turned it off. After that throttle body showed 42.9mV.

Does it mean that the throttle body has some electrical problems?

[VStar650CL]

No, the TB is gasketed onto a plastic plenum, so it doesn't have a hard block ground. That's no worry.

[Altima19]

No, the TB is gasketed onto a plastic plenum, so it doesn't have a hard block ground. That's no worry.

Ok, got it.

Thanks a lot for all your help!

[VStar650CL]

[Altima19]

Hi there, just wanted to post an update.

There’s currently 170 000 miles on it and that jerk is still there. Nothing changed from 133 000 miles.

I wonder if anyone else has encountered this problem?

[VStar650CL]

Does the engine RPM bounce when it jerks? Coasting at a decreasing speed, you may just be feeling the lockup clutch in the Torque Converter disengaging. That's normal, the car can't idle with the TC locked up so the TCM releases it when road speed drops below a certain point. The release isn't very noticeable on a new ride, but it can get a bit clunky as the transmission ages. If you have CVTz50, watch the lockup condition as you duplicate conditions where it jerks. If the jerk coincides with the lockup transition, you know it's harmless.

[Altima19]

Thank you VStar650CL for your input!

RPM bounces a little, about 40-50rpm. But there could be a delay which cvtz50 shows the values.
Yes, it coincides with the lockup condition. But still not sure why it happens since ~80k miles. Transmission wasn’t too old at that time. Now it has 170k miles and feels the same.
By the way, yesterday I replaced fluid with filters again. Nothing changed after that as well.

[VStar650CL]

I haven't done a deep dive on what causes the release to get clunky in old age, but keep in mind that there's a lot of hardware in between the TC and the tires. My feeling has always been that it's "accumulated tolerance", a little wear here and a little wear there adding up to enough to be palpable. I can tell you cars sometimes still do that after a new VB or even a new trans, so whatever underlies it isn't necessarily all in the gearbox or hydraulics. The CV's and the various splines must contribute too.

[Altima19]

Agree. Also probably it’s a good idea to check all the mounts (engine, trans). If they are good, then forget about it and just drive