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You are right the ctis breaker is on the 24v bus.

The fmtv ecu is 12 volt and the m939a2 one is 24 volt they are not cross compatible.

Does the software allow you to make permanent changes to the pressure settings in each mode?

I hope you dont mind me asking all these questions. On the M939A2 90 psi upgrade (for the M936A2 wrecker primarily) it appears to use the same wheel valves as the lmtv. How do these function properly.

Why is the front left different than the other valves? I was thinking I would only have to put a resistor on the positive side not the ground.

On the m939a2 trucks there was an upgrade for running higher pressure. It was a newer ecu, replacement pressure sensor and wheel valve upgrades to what appears to be the same ones as the lmtv uses. Is there any way to trick the first gen lmtv systems into running higher pressure by just changing...

There used to be rebuild kits for the m939a2 ctis valve body. I think it had new poppets and o rings. Maybe something available for the lmtv.

Just unplug the controller for now

Wheel valves cant just dump air. The manifold has to send a certain pressure to hold them open to allow for air dumping. Could be the manifold but if the system flashes hwy and then goes to run flat it seems to be sensing low tire pressure.

The system does a pressure test, sees low and sends air which is diluted thru the bad hub seal leak and tricks the wheel valves to dump. Do you hear a siren sound?

Sounds like a bad hub seal

I just watched your vid. Never seen that before. If they were all flickering I would say it could be harness/connection loss of power issue. But the highway light stays on. It's not supposed to do that. It's not a flashing scheme the lights do when there is an error. It's just going haywire.

I will see what I have Monday. They are not too expensive. I will warn you I have had ones that are happy in my test truck then not so much in others. Clean your wire harness plug connection lightly with an eraser.

I have a bunch of extras. Would have to test them. Sometimes they are finicky.

Somewhere around that pressure. You can use an ohm meter on yours see if its open with no air and closes at pressure. You can use a paperclip to jump the connector terminals and see if you ctis system comes on. my email is will atpawnking dotcom

I have used ones

Is there a part number for the complete adapter?

I have the laptop, software and comm box. Do you know where one can get a Y cable? Is the Y cable the same for M939A2 and LMTV use?

Not always on lmtv. Just indicates a hardware fault. The air tank pressure switch not closing will cause a time out error and give 5 solid leds. I believe pneumatic valve not responding can do the same.

Whats the best way to interface with the lmtv ctis control? Its my understanding that on the A1 C7 trucks that have data bus you can use a laptop with the dana software and access it thru the engine diagnostic port. Not sure about 3126 A1 trucks though. Supposedly there is an elusive Y cable in...