CTIS pressure settings increase - no programming, transducer, or module required.

Well this is going to make a few people (including myself) feel really silly......

I've been getting pretty deep into a CTIS diag on a friends truck and had the occasion to swap modules between my truck and his, and vice-versa. And I've been going over documentation and troubleshooting info and discovered something that's going to make a lot of you guys really happy and possibly regret one or more purchases.

First off - the Dana/Spicer CTIS controller used in the FMTV family does indeed contain multiple "programs". In fact the controller actually contains NINE different programs. These are accessed through all the various possible combinations of power, ground, and open circuit on pins M and Z of the CTIS controller connector (P110 on the schematic). The various FMTV schematics aren't always clear on this point - many of them show both of them having power, and some actually do show "MTV Only" on pin Z. From looking at my 2008 M1079 A1R compared to the 2001 M1088 A1 we can say that in these two examples the 4x4 truck has 24v fed to pin M and Z is not populated, and the 6x6 truck is the opposite - pin Z has 24v and M is non pinned.

The wiring on the truck determines which programming the controller runs when powered on. But there are actually 9 different programs - the FMTV's are only using 2 of them.

My apologies to Ronmar who suggested this may the case and I dismissed the possibility since the software makes NO mention of this nor does it allow access to any of the settings for other programs. You have to switch the wiring and reconnect the software.

The implications of this are:

A: Installing a controller from a 6x6 truck into a 4x4 truck will do exactly nothing on it's own.

B: Fooling the controller with an Amazon transducer isn't necessary - your controller already has higher pressure settings. Also this throws off the controllers atmospheric pressure reading.

Now since there are nine programs the two being used by our various trucks are +24v on M/open on Z or open on M/+24v on Z - there are 7 more programs that are just unused. What's on them? Well I haven't checked them all, but on my truck I did cut the power to pin M (so open circuit on both option pins), and the program it loaded is identical to the 6x6 default program.

So to get M1088 pressure settings on your LMTV or other truck with 55 psi highway mode, you can just cut the 1911 wire going to pin M at the controller connector. That's it. No other modifications required.

We verified that my 4x4 controller went to 81 psi highway on the M1088 harness, and also that the (green 2001 controller) went to 55 psi highway on my M1079 harness. So at least the A1+ trucks seem to conform to this.

*EDIT* - I have read in several threads that A0 trucks will work with A1+ controllers but the pressure settings and overspeeds are wrong. Likely a result of different programming selection via harness and different speed sensor settings since the A0 trucks are using the transmission speed sensors rather than the CAT ECM pulse per mile information. But with the right information it would be trivial to program a later CTIS module to work on the A0. @Lostchain and I have discussed setting up a full CTIS test bench so could easily program whatever into controllers if needed...... *EDIT*

Here's the default settings for the LMTV controller (except for my 90 mph highway overspeed setting):




And here's the program for both option pins open circuit:




Second point - with this information it's relatively easy to install a toggle switch to switch pin M or Z from +24v to open circuit or to ground and get easy access to 3 of the 9 programs. And with the right software and adapter you can program the pressure settings in each of those programs and have 12 different pressure settings available. There is a CTIS OFF indicator lamp in the dash and provision on the truck for a switch used in the optional arctic kit for toggling power to the controller - this is easy to wire in and can be used to cycle power and thus switch programs while driving. I haven't yet tested if the controller will switch programs on the fly or not and I'm not sure that's a good idea to recommend anyway - if it works it may not work on all of them - there's quite a few generations of the controller - green and black and of the black units there are variations - older black units will not coms with J1939 for example while newer ones will........

Nice work! I noticed the "MTV only" wire in the diagrams the other day. I have a 1096 and got an eBay replacement black controller (I believe second of the three versions) and have trying to get my ctis working, chasing leaks. I was able to verify 55psi is the highway setting it currently has. Need to check the pin out.

I managed to get 8 different settings by installing the Amazon transducer in series with the original transducer and installed a switch (I think it was a four pole switch) to toggle between the low and high transducers. Top psi is around 85 which works great for on road with my weight. I made a small label the reminds me what psi in each mode.

Keith Knight said:

I managed to get 8 different settings by installing the Amazon transducer in series with the original transducer and installed a switch (I think it was a four pole switch) to toggle between the low and high transducers. Top psi is around 85 which works great for on road with my weight. I made a small label the reminds me what psi in each mode. View attachment 906061

Click to expand...

My point is you can get the exact same effect with a SPST switch and a few inches of wire. No transducer, no plumbing, no 12 feet of wire, and it doesn't throw off the controllers atmospheric pressure reading. And with a SPDT switch, and a few more inches of wire to a ground you can have 12 pressure settings if you like. The controller was designed to have this feature. No need to fool it, throw off it's altitude compensation, and add a bunch more points of failure.

Totally agree, wish I had known a few years ago.

Awesome stuff.

I wish my controller wasn't bricked. I'm not too keen on replacing it given that the failure rate appears to be every other truck out there.

But great info for those with working controllers !

Third From Texas said:

Awesome stuff.

I wish my controller wasn't bricked. I'm not too keen on replacing it given that the failure rate appears to be every other truck out there.

But great info for those with working controllers !

Click to expand...

The Dana controllers are pretty good actually. Especially the later black unit that speaks J1939. That's the only one to get IMO.

The Arduino option(s?) are interesting but the truck I'm troubleshooting at the moment seems to have bricked one of those (lights up and then the display just fades away) and both his green Dana box and my later black Dana box have thus far survived without issue. Plus the Dana unit is environmentally protected (potted/sealed) and has a decent software interface for diagnostics - the Arduino wasn't able to tell us what's going on with the truck (multiple issues both pneumatic and electrical) but the Dana controller at least has test modes and fault codes, etc. With the ability to program it, the diagnostic capabilities, and now the ability to run up to 36 program settings via switch selection. Well it works just fine for me

I generally don't like to redesign the stuff that engineers spent thousands of man hours designing and testing and that has been revised and updated for 30 years now. I find it's often foolish.

Like the guys that delete the LBCD - I was speaking with an M1088 owner that has a truck so modified - apparently the starter jammed in the engaged position and this caused the alternator to overheat to the point it caught fire. The disconnect relay might have saved the alternator at least.

GeneralDisorder said:

The Dana controllers are pretty good actually. Especially the later black unit that speaks J1939. That's the only one to get IMO.

The Arduino option(s?) are interesting but the truck I'm troubleshooting at the moment seems to have bricked one of those (lights up and then the display just fades away) and both his green Dana box and my later black Dana box have thus far survived without issue. Plus the Dana unit is environmentally protected (potted/sealed) and has a decent software interface for diagnostics - the Arduino wasn't able to tell us what's going on with the truck (multiple issues both pneumatic and electrical) but the Dana controller at least has test modes and fault codes, etc. With the ability to program it, the diagnostic capabilities, and now the ability to run up to 36 program settings via switch selection. Well it works just fine for me

Click to expand...

Yeah, mine was a later black box off my 2008 truck. It had worked flawlessly a couple years then sadly went five-solid after I removed it to repaint the face of the heater. I was methodical in making sure the power was off and batteries disconnected. It just came on with five solid. I should toss it into a box and let you give it a look some day. I've no issue with the Arduino at present, but I'd not mind swapping back if the OEM controller were in fact not actually bricked.

I have interacted with quite a few 5 solid light failures, mine included, and that is not counting the other intermittent failures that have not degenerated to a 5 solid fault(beat on the controller to restore ops for a bit). So I would say yes they have a fairly high failure rate across this relatively small civilian LMTV owner community…

The LBCD would only open the disconnect relay and disconnect the batteries. It would not disconnect a hung starter being fed by a running alternator…
Pretty sure the LBCD was designed specifically to save the alt from the scary monster battery under the bed

Ronmar said:

I have interacted with quite a few 5 solid light failures, mine included, and that is not counting the other intermittent failures that have not degenerated to a 5 solid fault(beat on the controller to restore ops for a bit). So I would say yes they have a fairly high failure rate across this relatively small civilian LMTV owner community…

The LBCD would only open the disconnect relay and disconnect the batteries. It would not disconnect a hung starter being fed by a running alternator…
Pretty sure the LBCD was designed specifically to save the alt from the scary monster battery under the bed

Click to expand...

I've had one of the 5 light failures also. But the one and only Arduino I've touched was also bricked. So there's that. They have continued to make improvements in the controllers - the one I'm currently using is a 2012 black case unit that can coms with J1939. @Lostchain has a 2016 unit that's similar. I've only seen the older black J1708 boxes fail thus far. But just as easily could be due to age.

I was thinking the starter was on the battery side of the disconnect relay but yeah upon review it's not. Well that sucks. Service your starter occasionally I guess!

I would much rather have the Dana controller; though can't I have an Ardiuno and a spare for like half as many Franklins?

hike said:

I would much rather have the Dana controller; though can't I have an Ardiuno and a spare for like half as many Franklins?

Click to expand...

Not really, no. You can find the Dana controllers brand new for like $600 to $700. And used one's are $100 to $200 and will continue to land on the surplus market for decades in both new and used form. With the free software, an RP1210 adapter that you should probably have anyway if you have an A1+ truck, and a $100 laptop you can program them and diagnose with them.

How many of the Arduino units have been created? A few hundred maybe? The Dana unit has been built in the millions of units. Between military and industrial applications. spares, and 30 years of manufacturing. MILLIONS of them.

New:


Used:



There's TONS of them on the market. Too many for them to command a huge price.

I think the Arduino unit is like $400? Not sure on that. But you definitely can't buy two of them for half the price of the Dana/Spicer/Eaton units.

@GeneralDisorder my M1078A1 has 24+v at H and M. Nothing at Z. The new unit listed is meant for a M939. Any thoughts on which pins it will expect power? The backing label states: highway 81# wrecker, 70# others.

Once I get to our final tare weight (should be about 19,300#) I am expecting 65# - 70# to get a good tire chalk test—

The listing says MRAP, M939, FMTV, LMTV. Guessing it would fit an M35A3 also.... probably other stuff as well.

There are no stock programs I'm aware of that run 65 to 70 psi in HWY. You will have to program it. Also what you "guess" and what a tire chalk says and what the truck decides it's going to impose upon you and it likes best are not always the same. Tires play a big role here.

It doesn't matter which pins are powered unless you want more than one program at a time. Buy one and program it to your needs.

H and M is the standard 4x4 power profile. My M1079 A1R is the same. It will put most of these units into 55 psi HWY mode as in my pictures.

i’m 2 toggle switches, 1 pushbutton, 1 relay and a pressure gauge into mine… Just sayin

GeneralDisorder said:

The listing says MRAP, M939, FMTV, LMTV. Guessing it would fit an M35A3 also.... probably other stuff as well.

There are no stock programs I'm aware of that run 65 to 70 psi in HWY. You will have to program it.

It doesn't matter which pins are powered unless you want more than one program at a time. Buy one and program it to your needs.

H and M is the standard 4x4 power profile. My M1079 A1R is the same. It will put most of these units into 55 psi HWY mode as in my pictures.

Click to expand...

My 2002, M1083A1, came from GovPlanet. From what I can see from the evidence that was in the truck, and it's condition of the truck, it mostly came directly from the military, so no previous civilian owner that I can see.

The CTIS was disconnected when I received it. Once I got the truck running and put on new tires on, inflated to 80 psi, on I hooked the CTIS back up.
Once the CTIS was hooked up and the truck started, I heard it letting air out of the tires. I checked the psi in each tire and all were at 70 psi.

I put the CTIS in sand mode to air down and then back to HWY mode to air back up. It aired the tires back up to 70 psi..

So this is unusual? (I would have liked the CTIS to inflated to 80 psi in HWY mode.)

Tom.

TomTime said:

My 2002, M1083A1, came from GovPlanet. From what I can see from the evidence that was in the truck, and it's condition of the truck, it mostly came directly from the military, so no previous civilian owner that I can see.

The CTIS was disconnected when I received it. Once I got the truck running and put on new tires on, inflated to 80 psi, on I hooked the CTIS back up.
Once the CTIS was hooked up and the truck started, I heard it letting air out of the tires. I checked the psi in each tire and all were at 70 psi.

I put the CTIS in sand mode to air down and then back to HWY mode to air back up. It aired the tires back up to 70 psi..

So this is unusual? (I would have liked the CTIS to inflated to 80 psi in HWY mode.)

Tom.

Click to expand...

In the end CTIS doesnt know pressure, it knows voltage. It relies on the pressure transducer and its circuit to make that conversion…

TomTime said:

My 2002, M1083A1, came from GovPlanet. From what I can see from the evidence that was in the truck, and it's condition of the truck, it mostly came directly from the military, so no previous civilian owner that I can see.

The CTIS was disconnected when I received it. Once I got the truck running and put on new tires on, inflated to 80 psi, on I hooked the CTIS back up.
Once the CTIS was hooked up and the truck started, I heard it letting air out of the tires. I checked the psi in each tire and all were at 70 psi.

I put the CTIS in sand mode to air down and then back to HWY mode to air back up. It aired the tires back up to 70 psi..

So this is unusual? (I would have liked the CTIS to inflated to 80 psi in HWY mode.)

Tom.

Click to expand...

It depends on which controller you have, and the power/ground/open state of pins M and Z. And as Ronmar pointed out you could have a skewed pressure transducer signal, or someone changed the programing with the diagnostic software. Best way to know for sure is to hookup the diagnostic software and see what the controller sees and is asking for.

GeneralDisorder said:

Not really, no. You can find the Dana controllers brand new for like $600 to $700. And used one's are $100 to $200 and will continue to land on the surplus market for decades in both new and used form. With the free software, an RP1210 adapter that you should probably have anyway if you have an A1+ truck, and a $100 laptop you can program them and diagnose with them.

How many of the Arduino units have been created? A few hundred maybe? The Dana unit has been built in the millions of units. Between military and industrial applications. spares, and 30 years of manufacturing. MILLIONS of them.

New:

CTIS Tire Pressure Control Mrap M939 FMTV LMTV 676422 6110-01-268-8739 | eBay

For sale is a New Dana Spicer/International CTIS system. The part number is 676422. The NSN number is 6110-01-268-8739 Here are the specs HUES Color Black.

www.ebay.com

Used:

m939a2 ctis controller m923a2 m936a2 m939 m923 m934a2 m931a2 | eBay

The colors will be green. Buttons will have wear and tear and will be faded from age. We also have other take off CTIS Parts and have any 5 ton Parts you may need for your m939. We are solely focused on 5 tons let us know where we can help you- Jim 5076762972.

www.ebay.com

CTIS Control Panel Pneumatic Tire Inflation Spicer Dana 1mvz1-673990 | eBay

CTIS Control Panel Pneumatic Tire Inflation Spicer Dana 1mvz1-673990 . Condition is Used. Shipped with UPS Ground.

www.ebay.com

There's TONS of them on the market. Too many for them to command a huge price.

I think the Arduino unit is like $400? Not sure on that. But you definitely can't buy two of them for half the price of the Dana/Spicer/Eaton units.

Click to expand...

Ordered an Arduino prototype ($320 including shipping to the US) to be another beta tester (less than a 100 of us I understand). Though you influenced me to try a new Dana in the box as well, as the idea of having several program options is interesting. Though I don't play well with Windows: Linux or a MAC for me. If I can find the hardware for an RP1210 to contact to my laptops and learn what the signal sets are telling me that could be fun. Or perhaps you will help me program the CTIS as may be appropriate in the future.

Again, I appreciate all the knowledge and willingness to share ideas here. Thank you @GeneralDisorder @Ronmar @Third From Texas @Keith Knight and those I missed–

hike said:

Though I don't play well with Windows: Linux or a MAC for me.

Click to expand...

As a software engineer in a former career path I understand the sentiment and for me the disembodied hand of Steve Jobs ghost can keep his bony fingers the hell out of my wallet..... but all that aside - the military standardized on Windows so if you want to have any meaningful coms with the truck you'll load up an old laptop with a hardware serial port and a copy of windows 7 right quick or you'll be banished to the stone age of troubleshooting with tea leaves and the parts cannon. CAT ET is an ABSOLUTE NECESSITY for A1+ trucks to have any hope of figuring out why the check engine light came on and you're in limp mode doing 8mph on the freeway.

Tow trucks for FMTV's are absurdly expensive BTW. Assuming you don't know anyone at the local national guard base with a HEMTT wrecker and nothing better to do.