Manual Mode in 4L automatically shifts up

[armo1985]

Hi Everyone,

My last trip away on the weekend, I noticed when I was stuck in a bog hole and trying to power out in 4L, manual mode 1st gear, it would jump straight up to 2nd then third, with each gear change causing an almost complete loss of power momentarily, getting rid of any momentum built up to get out. Is there a way to prevent the auto shift up? Maybe trying 4H with VDC off?

2012 d40 ST auto.

 

[bods]

I'd say it's a similar problem to what the guys with 550s were having upshifting going downhills...

Seems a bit silly that nissan don't make 'manual mode' a proper manual mode...

There were threads, people have gone to nissan and been told basically to get over it, they won't change it...

 

[Old.Tony]

It's a quirk with the 550's gearbox (which comes from the Z350/370), the computer isn't supposed to upshift and doesn't in 2HI/4HI but for some reason does in 4LO.

As above, Nissan aren't in a hurry to change it. We haven't heard what they're doing for the D40 range, the D22 is being replaced by the D23 and there's been one mention of a D50 on the horizon. Also a rumour that they'll just make a few more Titans and ship those out here in place of the D40. I don't think they'll ever look back at the 550's box and do anything about it.

There IS a fix (workaround). Raptorthumper worked out that if the car doesn't know it's in 4LO, it obeys the manual command. Essentially you override the computer's control of the transfer case and (electrically) manually change the vehicle into 4LO. The computer doesn't know, so it doesn't make the mistake and you can use 4LO in manual mode perfectly.

 

[LLadnar]

Wonder if you can get a stand alone computer for the Z350 tranny.

 

[Old.Tony]

I think there's something in the CAN bus that's causing it. Maybe the 4LO signal duplicates the "get out of manual mode" signal? The only way around something like that is to change the code for the 4LO command, and then make the TF control listen to the new command.

I'm just guessing of course. Be interesting if we could put a packet sniffer on the CAN BUS and see what command codes are being sent to:

a) enter manual mode
b) exit manual mode
c) enter 4HI
d) enter 4LO

I have a strong suspicion that b) and d) are the same code.

 

[Jase V9X]

Hi guys
Even in 2 & 4Hi manual mode it will still change - just at higher revs ( approx. 4000 from memory)

 

[Old.Tony]

That might be a safety thing. Diesels don't like being highly revved, especially on the lower cetane fuels. There's a governor that limits the engine to 5000rpm anyway (ECU function).

I've managed to obtain a specific type of OBD adapter that I can modify to allow me to write data to the ECU. I also have obtained some software that should let me do it. I haven't tried playing with it yet, but my intention with this software is to do the following things:

1) Instruct the ECU to ignore the state of the EGR valve.
2) Instruct the ECU to ignore the state of the HO2S in the exhaust and
3) Instruct the ECU to overlook the CAT reductant injection

My initial foray into it will be look-only though. I don't think mine has any gearbox data apart from the current gear that it's in, the TCM self-manages everything else. If the 550 presents the same data then the only means we will have of changing the way the gears are managed is to reprogram the TCM.

 

[bods]

Hey tony,
Any chance of sharing what obd adaptor you got hold of that should let you write to the ecu?

 

[Old.Tony]

It has to be modified. This is the one that I bought, I haven't started playing with it, only managed the remote aux system voltage display today plus a ton of gardening. Got heaps more on tomorrow, I don't know how I'm going to get it all done.

My ECU gadget sits a fraction lower on the list of priorities, but I will get to it soon enough. I want to play with my car!

If you buy one, be careful, the guy has pirated software on the disk he supplies and there's a trojan inside the keygen.

 

[LuckyPhil]

That might be a safety thing. Diesels don't like being highly revved, especially on the lower cetane fuels. There's a governor that limits the engine to 5000rpm anyway (ECU function).

I've managed to obtain a specific type of OBD adapter that I can modify to allow me to write data to the ECU. I also have obtained some software that should let me do it. I haven't tried playing with it yet, but my intention with this software is to do the following things:

1) Instruct the ECU to ignore the state of the EGR valve.
2) Instruct the ECU to ignore the state of the HO2S in the exhaust and
3) Instruct the ECU to overlook the CAT reductant injection

My initial foray into it will be look-only though. I don't think mine has any gearbox data apart from the current gear that it's in, the TCM self-manages everything else. If the 550 presents the same data then the only means we will have of changing the way the gears are managed is to reprogram the TCM.

Real keen to learn more about this will be watching.

 

[bods]

It has to be modified. This is the one that I bought, I haven't started playing with it, only managed the remote aux system voltage display today plus a ton of gardening. Got heaps more on tomorrow, I don't know how I'm going to get it all done.

My ECU gadget sits a fraction lower on the list of priorities, but I will get to it soon enough. I want to play with my car!

If you buy one, be careful, the guy has pirated software on the disk he supplies and there's a trojan inside the keygen.

Hey tony..

Not really the right thread, but oh well. After researching what protocol to ecu uses for programming it appears you need a j2534 compatible interface cable.

I have got one on the way from ebay and have software on the laptop so will see if it works when it rocks up...

 

[camo.b]

Has anyone tried the consult 2 or 3 eba adapters?

 

[bods]

Has anyone tried the consult 2 or 3 eba adapters?

Just had a bit of a quick look at them.. for the 200 bucks they want for the consult 3, if the software it comes with lets you turn ecu functions on and off, thats probably not a bad price...

If you can disable stuff like dpf regen and egr, possibly adjust auto gearbox settings, then it could definitely be worth it...

I'll have a play with my 30 odd buck ebay cable when it gets here and see how it goes.. I do have a d22 though, so don't have any need for auto gearbox or dpf commands anyway. .....

But if I can adjust fuel tables and get a bit better performance and economy out of it I'll be happy....

 

[charlie91]

yeah got a 2014 D40 ST AUTO and its really annoying and quite dangerous when using the gears to slow and more important control your hill decent and all of a sudden it launches you forward when it automatically up gears when in Manual select / TripTronic mode. Suppose just something I have to live with.

 

[ckdxr]

mine is doing the same thing but in auto low range as well as manual, in manual mode it was shifting to 5th doing 25kph on a at 2000rpm. pretty annoying when you need a run up
to get through soft sand and it dies in the arse half way through. has only been since nissan re-programmed the trans ecm because it was clunking downshifting gears. would love to get this sorted as im sick of being snatched out by busted arse old hilux's and 80 series cruisers.