Tow Mode without the button?

mnypitTBEXT

Original poster
Member
Jan 29, 2012
133
OK so we were browsing my tune compared to my buddy's Avalanche and it seems that the tow mode is there, but I do not have a button to activate it and he does.

How do I activate the tow mode?

I have a 05 TB EXT with a 5.3 and tow package with 3.73 rear. Not really understanding why we wouldnt have the button?
 

Me007gold

Member
Nov 20, 2011
1,106
There is no such thing as "tow mode" on the GMT360's, there is a chance you can turn the overdrive off with the button on the shifter, if your vehicle is equiped with that feature
 

mnypitTBEXT

Original poster
Member
Jan 29, 2012
133
Me007gold said:
There is no such thing as "tow mode" on the GMT360's, there is a chance you can turn the overdrive off with the button on the shifter, if your vehicle is equiped with that feature

Tow mode does not turn off OD, it changes other things, but does not lock out OD. I can jsut put it in 3 if that is all I wanted.

It is in the tune, I just have to figure out how to activate it. That is what I am looking for. I looked in the owners manual and it was not even an option. Strange that they would include it in the tune but not allow us to access it?!? Maybe there is a pin in the PCM that can be grounded or applied power to in order to make it work?? Or is it in the body module???
 

willn513

Member
Dec 4, 2011
918
These vehicles do not have a TOW/HAUL mode on them. The Avalanches do. Different vehicles all together.
 

mnypitTBEXT

Original poster
Member
Jan 29, 2012
133
willn513 said:
These vehicles do not have a TOW/HAUL mode on them. The Avalanches do. Different vehicles all together.

Obviously nobody is reading my post. I AM WELL AWARE THAT THESE VEHICLES DO NOT HAVE TOW/HAUL.

I have said it twice now. It IS in the programming on the PCM. We have found it with HPTuners. IT IS THERE!! My question is, has anyone activated it, and if so how. I am sure it is a simple pinout going to ground with a switch. Just need to know which one.
 

The_Roadie

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Nov 19, 2011
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Portland, OR
In my MANY years on three forums, I don't recall ANYONE ever trying to get it to work. There are 32 unused pins on the 3 PCM connectors. If you find the pin the Avalanche uses to read the tow switch, I can confirm it's unused on the GMT360 platform.

The software could have been put there by the programming team, and management decided against activating it. There is a LOT of code in the PCM we would LOVE to hack, and it's all locked up against tampering a lot tighter than the tables we can fiddle with using EFILive or HPTuners. If I was part of the evil GM management team, I would have put the disabling control in the section of protected code, not an option that could be flashed into working. They're not dumb, and they KNOW about the tuning industry.

In case they were goofy, and failed to lock down the code, and exposed the control wire on one of those 32 unused pins, then you have a chance. Locate the control wire on an Avalanche schematic, confirm that it's the usual "ground the pin to activate the option" logic, and then you can try it.

You'd be the first, and thus - famous. :thumbsup:
 

mnypitTBEXT

Original poster
Member
Jan 29, 2012
133
the roadie said:
In my MANY years on three forums, I don't recall ANYONE ever trying to get it to work. There are 32 unused pins on the 3 PCM connectors. If you find the pin the Avalanche uses to read the tow switch, I can confirm it's unused on the GMT360 platform.

The software could have been put there by the programming team, and management decided against activating it. There is a LOT of code in the PCM we would LOVE to hack, and it's all locked up against tampering a lot tighter than the tables we can fiddle with using EFILive or HPTuners. If I was part of the evil GM management team, I would have put the disabling control in the section of protected code, not an option that could be flashed into working. They're not dumb, and they KNOW about the tuning industry.

In case they were goofy, and failed to lock down the code, and exposed the control wire on one of those 32 unused pins, then you have a chance. Locate the control wire on an Avalanche schematic, confirm that it's the usual "ground the pin to activate the option" logic, and then you can try it.

You'd be the first, and thus - famous. :thumbsup:

Yep, I have searched all the forums and found nothing. We are currently locating the differant pinouts and trying to figure out if one of them will activate it. I think every other GM product with a 5.3 has it, so........

You may be right though, it might just be locked. I am no tuning guru, and we are just experimenting, so we will see.
 

Instrumental

Member
Jan 29, 2012
268
I've got the 5.3, adding the tow mode would be a nice upgrade. Good luck, and please report back!
 

mnypitTBEXT

Original poster
Member
Jan 29, 2012
133
OK just a thought. What if I just do some tweaks to the PCM for towing? We dont drive it much anymore, except when we tow. I have heard that the tow/haul mode may be a good thing to leave on all the time to help cool/save the transmission anyway.

So what changes could we make permanently to a stock vehicle to help when towing? I may add a CAI and exhaust, but no big plans in the forseable future.
 

navigator

Member
Dec 3, 2011
504
mnypitTBEXT said:
OK just a thought. What if I just do some tweaks to the PCM for towing? We dont drive it much anymore, except when we tow. I have heard that the tow/haul mode may be a good thing to leave on all the time to help cool/save the transmission anyway.

So what changes could we make permanently to a stock vehicle to help when towing? I may add a CAI and exhaust, but no big plans in the forseable future.

I don't have either but I would think a tranny cooler and some kind of OBDII reader to monitor tranny temps would be the best two things to have if you tow a lot.
 

Mark20

Member
Dec 6, 2011
1,630
Having a Silverado with tow/haul I can confirm it only changes the shift points. First gear is much taller making you think somethings broken when you pull away in tow mode but nothing hitched, takes forever to go to 2nd. Whether its the different shift points or just some increased minimal time between shifts, any tendency to hunt gears is reduced.

I sometimes use it when towing my camper but I am at only about 50% of tow capacity.
 

The_Roadie

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Nov 19, 2011
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Portland, OR
Mark20 said:
Having a Silverado with tow/haul I can confirm it only changes the shift points.
Software confirms no changes to any spark timing, cam advance, injector pulse widths, AFR, or other tables? Or are you just reporting no butt-dyno changes other than shifts?
 

mnypitTBEXT

Original poster
Member
Jan 29, 2012
133
navigator said:
I don't have either but I would think a tranny cooler and some kind of OBDII reader to monitor tranny temps would be the best two things to have if you tow a lot.

As much as we tow, I already installed a cooler years ago. I am actually trying to get a little more performance out of it when I tow.
 

RayVoy

Member
Nov 20, 2011
939
the roadie said:
Software confirms no changes to any spark timing, cam advance, injector pulse widths, AFR, or other tables? Or are you just reporting no butt-dyno changes other than shifts?
We'll let Mark answer your question. However, I can tell you there is a different table used in the PCM. The "performance" table changes the transmission shift points and increases the shift pressure thus, reducing "hunting". It also adds a forced downshift, providing grade retard. This forced downshift is activated when the brake is applied going down hill and released when the gas is toed. I also changes the lane change signal from 3 flashes to 6 flashes.
There is a probability that torque management is also changed, but I have not been able to verify.
 

Mark20

Member
Dec 6, 2011
1,630
Yes I measured everything with Roadie's patentend Butt-Dyno! :biggrin:

Really other than the shifting being different I don't feel or notice any other significant changes. I've unintentially stompped the accelarator in haul mode when leaving a stop sign while towing and did a good job of spinning the rear wheels. Don't necessarily want to repeat that again but if I can find myself in a similar situation - and safe - I'll try it in tow mode.

I'll admit there could be subtle changes to to the Silverado's ignition but the accelartion otherwise feels the same between tow and haul modes.

Again this is on my 2011 Silverado.

Note to self: Back up any statements with facts esspecially when Roadie is around!
 

The_Roadie

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Nov 19, 2011
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Portland, OR
RayVoy said:
...also changes the lane change signal from 3 flashes to 6 flashes....
Huh? Is this a new feature for drivers without the attention span to keep their hand on the signal lever until the lane change is done? :rotfl: 3 flashes around here isn't enough for the numbnuts to notice.

I had a customer tell me once (when I claimed a system performance point not in the published spec): "In God we trust......all others bring data."
 

ScarabEpic22

Member
Nov 20, 2011
728
Ive thought about this a lot and looked into it a bit, first off you have a different ECM/TCM in an 05 vs your buddy's Avalanche that has a PCM. Just because the T42 TCM you have (and all 05-09 V8s in our trucks do, plus the 08-09 I6) has tow mode in a fullsize truck doesnt mean we can add it. If the pin isnt used, you *might* be able to wire it up and test it, BUT GM uses different OSs across all vehicles and what is x output on an fulllsize wont be x on our trucks.

I looked at it a few years ago but didnt pursue it, honestly it just raises the shift points, increases line pressures, and reduces shift times. Might drop TM a little, cant remember. Basically all things that a tune does.
 

mnypitTBEXT

Original poster
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Jan 29, 2012
133
ScarabEpic22 said:
Ive thought about this a lot and looked into it a bit, first off you have a different ECM/TCM in an 05 vs your buddy's Avalanche that has a PCM. Just because the T42 TCM you have (and all 05-09 V8s in our trucks do, plus the 08-09 I6) has tow mode in a fullsize truck doesnt mean we can add it. If the pin isnt used, you *might* be able to wire it up and test it, BUT GM uses different OSs across all vehicles and what is x output on an fulllsize wont be x on our trucks.

I looked at it a few years ago but didnt pursue it, honestly it just raises the shift points, increases line pressures, and reduces shift times. Might drop TM a little, cant remember. Basically all things that a tune does.

Would you suggest tuning it this way permanently? We dont drive it much anymore and I want it to tow better. Would there be anything else you would change in a simple tune without mods? I dont have a bunch of money to spend right now. I am trying to do this on the cheap for the time being.
 

ScarabEpic22

Member
Nov 20, 2011
728
mnypitTBEXT said:
Would you suggest tuning it this way permanently? We dont drive it much anymore and I want it to tow better. Would there be anything else you would change in a simple tune without mods? I dont have a bunch of money to spend right now. I am trying to do this on the cheap for the time being.

For the most part, yes. Especially if you tow a lot with it, a tune would set it up much nicer. I'd love to sell you a tune, however I havent had a chance to tune an 05-06 5.3L TB yet so I cant do it. Talk to Alvin at PCMofNC for a tune.

Chevy Trailblazer SS and 5.3L

Even if you were able to add a pin and switch to the TCM to activate tow mode, you'll still need a tune because GM didnt bother setting up those tables in the TCM. They're blank so it would be worse than stock, ie wouldnt shift!
 

mnypitTBEXT

Original poster
Member
Jan 29, 2012
133
ScarabEpic22 said:
For the most part, yes. Especially if you tow a lot with it, a tune would set it up much nicer. I'd love to sell you a tune, however I havent had a chance to tune an 05-06 5.3L TB yet so I cant do it. Talk to Alvin at PCMofNC for a tune.

Chevy Trailblazer SS and 5.3L

Even if you were able to add a pin and switch to the TCM to activate tow mode, you'll still need a tune because GM didnt bother setting up those tables in the TCM. They're blank so it would be worse than stock, ie wouldnt shift!

I was just thinking it would be nice to be able to change back to stock with a button. Another question though, is there a handheld that can store differant tunes so I can swap back and forth? Maybe get a performance tune and a towing tune.
 

Mark20

Member
Dec 6, 2011
1,630
the roadie said:
Huh? Is this a new feature for drivers without the attention span to keep their hand on the signal lever until the lane change is done? :rotfl: 3 flashes around here isn't enough for the numbnuts to notice.

I had a customer tell me once (when I claimed a system performance point not in the published spec): "In God we trust......all others bring data."

I wish it was 4 personally. What can get confusing is that the Voy does not have this feature but the Silverado does. Roadie is probably right, hold the stalk for as long as you need it.
 

jimmyjam

Member
Nov 18, 2011
1,634
I have a tow/haul button in my astro van. it waits much longer to shift in part throttle and the converter is locked most of the time and it almost never goes into OD but I generally don't tow faster than 50mph in that thing

mnypitTBEXT said:
I was just thinking it would be nice to be able to change back to stock with a button. Another question though, is there a handheld that can store differant tunes so I can swap back and forth? Maybe get a performance tune and a towing tune.

you maybe interested in superchips flashpaq
 

ScarabEpic22

Member
Nov 20, 2011
728
mnypitTBEXT said:
I was just thinking it would be nice to be able to change back to stock with a button. Another question though, is there a handheld that can store differant tunes so I can swap back and forth? Maybe get a performance tune and a towing tune.

Yes, EFILive's AutoCal is exactly what you want. Lets you store a few tunes from your tuner and flash them whenever you want. But, the hardware alone is $300 without a tune, so its more like $500-600 for an AutoCal + tune(s).
 

mnypitTBEXT

Original poster
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Jan 29, 2012
133
ScarabEpic22 said:
Yes, EFILive's AutoCal is exactly what you want. Lets you store a few tunes from your tuner and flash them whenever you want. But, the hardware alone is $300 without a tune, so its more like $500-600 for an AutoCal + tune(s).

I am finding the same thing on the button that has been said here. I ahve asked on several sites and am getting all the same info.

OK, well, since I already have the credits on HPtuners, maybe I will just order an email tune from PCM. Then I just have to drive over to my buddy's house to change things. So what is the differance between PCMforless and PCM of NC??? Looks like identical websites.

So now the question is what do I tell him to do in the tune for best towing, and all around performance? If I do mods later, is there a charge to adjust it?
 

mnypitTBEXT

Original poster
Member
Jan 29, 2012
133
Speaking of Superchips, how good are their tunes? Superchips is right in the next town, Sanford FL. For what I am looking for, would they work? Or would it just be better to get tow/performance tune from PCM?
 

BRomanJr

Member
Dec 9, 2011
371
mnypitTBEXT said:
Speaking of Superchips, how good are their tunes? Superchips is right in the next town, Sanford FL. For what I am looking for, would they work? Or would it just be better to get tow/performance tune from PCM?

I am running an older Tune from Superchips (see my signature), it uses a handheld programmer with built-in Tunes that I got used for $40 on E-Bay.

Mostly got it to modify the rear diff gear when I changed from 3.73 to 3.42. Using the 87 octane Tune for mileage and am very happy with it overall, changed shift points slightly. (no more double shift into second).
 

ScarabEpic22

Member
Nov 20, 2011
728
If you've already paid for HPT credits, just call up Alvin and buy a tune from him. Usually a performance tune and a towing tune are exactly the same on the engine side for gas engines (unlike a diesel) but the transmission tune is different. Ask if he'd be willing to make 2 trans tunes for you, then swap when you feel necessary.

Honestly I wouldnt use any handheld unless it was an AutoCal (and whatever HPT has coming down the line) loaded with custom tunes, every handheld Ive seen leaves a lot to be desired. I think either SCT or Superchips has the ability to flash custom tunes from the manufacture.
 

mnypitTBEXT

Original poster
Member
Jan 29, 2012
133
ScarabEpic22 said:
If you've already paid for HPT credits, just call up Alvin and buy a tune from him. Usually a performance tune and a towing tune are exactly the same on the engine side for gas engines (unlike a diesel) but the transmission tune is different. Ask if he'd be willing to make 2 trans tunes for you, then swap when you feel necessary.

Honestly I wouldnt use any handheld unless it was an AutoCal (and whatever HPT has coming down the line) loaded with custom tunes, every handheld Ive seen leaves a lot to be desired. I think either SCT or Superchips has the ability to flash custom tunes from the manufacture.

Yeah, that is what I was thinking. I only mentioned Superchips because I can be at their offices in about 15 minutes. I have already been in contact with Marshal through PM, should I PM Alvin?
 

ScarabEpic22

Member
Nov 20, 2011
728
mnypitTBEXT said:
Yeah, that is what I was thinking. I only mentioned Superchips because I can be at their offices in about 15 minutes. I have already been in contact with Marshal through PM, should I PM Alvin?

If you're already talking to Marshall, then I wouldnt worry about contacting Alvin. They work in the same place, just tell them what you're trying to do and Im betting they'll be able to help you out.
 

mnypitTBEXT

Original poster
Member
Jan 29, 2012
133
Just placed my order.
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
mnypitTBEXT said:
So what is the differance between PCMforless and PCM of NC??? Looks like identical websites.

They changed the name from PCMforless to PCM of NC. But they probably told you that already.
 

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