VStar650CL

ASD, chances are a regular OBD-II pocket reader won't upload the P1815. The TCM throws the code, not the ECM. Most pocket readers only read the ECM and sometimes the ABS and Airbag. Chances are you'll need a higher-end reader. Since it's going in for maintenance, I'd suggest having them put the CONSULT3+ on it and see if it's still there (it may have cleared through SRT if it's been too many key cycles since it occurred, but it's certainly worth a look).

Sorry I haven't jumped in lately. I've been preoccupied with a couple of nasty water-leak cases the past few days. ASD, if you can't make yours do it, I don't know why. I've now tried every NV on our lot (total of 7) and they all did it readily with gentle pressure. I'm tempted to think maybe your switch was built on a better day than the rest of them. After talking to Wollip on the phone, he told me perhaps he was pressuring the button "in anticipation of a shift" when he was on hills where he knew a shift would be needed. I can relate to that being a left-footed braker, I often catch myself unconsciously "dragging the pedal" in anticipation of an upcoming decel or stop. Same principle. My feeling is that Wollip's washer-guard will work fine, if not as neatly as a purpose-designed ring or boot. For the record, I'm as disappointed as anyone that this problem exists at all. Like the chain of events leading up to any accidental crash, there are multiple design issues in play, changing any one of which would "break the chain" and obviate the whole issue. A snap-action mechanism, a recessed button, a much longer error-timeout. Change any one of them and the whole problem disappears. Aargh. I told Wollip I plan to investigate button-protection boots in the electronics supply houses, Mouser, Newark, Digi-Key etc. If I come across something that looks nice and has the right diameter and depth to slip over an NV shifter, I'll let y'all know.

Unless the button itself is failing intermittently, it's really the only thing that can cause the behavior. It is, after all, a "button check" algorithm. According to the engineers, except for actual failures in the button or associated wiring, they've never seen it occur from any other cause.

No, the firmware doesn't work that way. When it throws the DTC, it always reverts to automatic shifting. I presume that's the reason, so you can never get stuck in a manual gear.

Update: I don't have a '12 here on the lot, but I tried it on a '15. Either NNA is wrong about the "press and hold" or they've changed the firmware between '12 and '15. I couldn't reproduce it in that manner. BUT, I could cause it every time with just a bit of gentle pressure on the button. In fact, I triggered it accidentally once as I was shifting into drive, with my thumb in the natural position on the end of the lever. I bet that's responsible for a lot of instances. I think it could be completely prevented by making a "button guard" from a suitable diameter of rubber hose extending just beyond the end of the knob.

Well, the engineers on this side of the pond (NNA) came through for our DTS, but this is an answer that will take some explaining. BTW, Wollip, I tried calling your cell a couple times this afternoon but mine was acting up and I couldn't keep/get reception. I'll just let you read and you can call me tomorrow on the shop phone. Here's the story to date: The Meter didn't solve it, but Wollip drove the vehicle to me when it acted up, without shutting the truck off. There weren't any diagnostic codes (DTC's) in it before, but this time it showed up with an obscure P1815 code that specifically applies to the Manual Mode switch. Trouble is, the documentation is awfully fuzzy. I wanted to paste a copy so you could all see it, but the website doesn't like any of my graphic formats. Basically, it says the Transmission throws the code whenever it sees "an impossible (button) input pattern" for 2 or more seconds. Okay, so what's an "impossible input pattern"? That's where our DTS came through. Same deal with the wiring diagram, but for those of you who might understand, it's a simple grounding-switch setup with pullup resistors in the Meter to provide 12V bias. The hitch is, the Manual Button is double-throw with the paddle only grounding through the normally-closed contact. This means the paddle can't ground when the M-switch is pressed, preventing the button and paddle from operating at the same time. There's also a center throw on the paddle that is also always grounded, except when the button is pressed. So the paddle center pin signal always goes high (12V) when the M-button pin low, and vice versa. It's supposed to increase reliability. There is, of course, firmware in the Meter that reads and decodes all four switch lines. That's where it gets murky. The NNA engineer called it a "user induced" condition, implying that the driver causes it, but that isn't wholly accurate. The firmware interacting incorrectly with the driver is a more apt description. Bear in mind that any good firmware runs "self-tests" and detects errors, and in a keypad system, that includes stuck keys. This will all come together when I describe the two conditions that cause the P1815: 1) The M-button is held for 2 seconds or more. In this case the Meter decides the button is mechanically stuck, tells the Transmission to generate a P1815 and stops looking at the button. It won't signal you that it has a problem, just continue to ignore the button until the key is cycled and the button (which has since been released) passes boot-up self-test. The fix is to make sure you only, ever, press the button momentarily. Never hold it, your Manual Mode will quit. 2) The M-button and paddle lines go high at the same time for 2 seconds or more. This can happen if you're resting your hand on the shifter and the button is accidentally pressured by the palm or heel of your hand. The "normally closed" switch throw breaks but the corresponding "make" puck isn't making contact. Same result, the Meter ignores the button and the Trans throws a code until the key is cycled. The fix is, rest your hand someplace else or in some other orientation. Otherwise, your M-mode may occasionally quit. This is only an issue because the firmware guys made the "stuck-button timeout" so short. Having written quite a lot of realtime firmware, I can vouch that most keypad-driven devices have longer timers on input errors; tens of seconds or even minutes. But, the NV's Meter is what it is. There's no way to reprogram those sorts of operating parameters. Perhaps a note in the Owner's Manual and/or Service Manual would have been nice, I'll try to noodge Nissan in that direction. The silver lining is, now everybody will know what causes this and how to avoid it.

Put the new Meter in this morning with instructions for Wollip to bring us the truck without cycling the key if it happens again. I think that's the only way to isolate the problem if it still exists; at least the Consult3+ will be able to identify which system is rejecting the button. Hopefully the latch-up thesis is correct and it's a non-issue. Sad to say, still no reply from Japan. Lately the reman house hasn't been requesting Meter cores back, so in 30 days I may be able to dissect the old unit and give y'all an update on the exact circuit and what went wrong inside.

Least I can do. Sounds like the answer might matter to more folks than you and me.

I'm the "Gene" Wollip mentioned, pleased to meet y'all. By way of introduction, I'm a Nissan/ASE certified electical specialist with an engineering background. I'm writing because I was concerned to discover that ASDDad had the same issue, so maybe Wollip's problem is something all Nissan technicians will need an answer for. Some of you may be familiar with the old Sherlock Holmes quote, "When you have eliminated the impossible, whatever remains, no matter how improbable, must be the truth." Some electrical issues can only be diagnosed that way, by process of (sometimes painful or unlikely) elimination. It's especially true when "smartware" is involved, because no service manual gives a technician access to the code, or even a flowchart of how a device "thinks". In this case, despite the intervention of a Nissan field engineer, we still don't know if it's even possible for trans heating to cause Wollip's issue. Only the firmware programmers in Japan know the answer, and they haven't told us. To help better-understand the problem, there are actually two firmware programs involved, the TCM (transmission controller) and the Meter (dash cluster). The way the NV is constructed, there is no direct link between the Manual Shift button and the TCM. The Meter monitors the button, then sends a CANbus message to the TCM when the button is detected. So, in Newtonian terms, what we have is a multiple-body problem. We can only try solutions in order of likelihood until something works. The good news is, our field engineer is an excellent guy who's very good at his job. He immediately saw what I saw in the wiring -- that the 12 volt signal from the button needs to be translated to a lower voltage for the Meter's microcontroller, and that's usually done with a CMOS "buffer" chip. Certain manufacturing flaws can cause the inputs on those chips to "latch" under certain conditions, meaning they will no longer "see" the voltage applied to them. That is, until the power is cycled, allowing the latch to clear. This seems to both of us the most likely scenario by far, and it completely fits the symptoms of needing to cycle the key. So we've ordered Wollip a Meter. He'll need to tell all of us whether it worked. If we happen to hear from Japan in the meantime, I'll keep y'all posted.