ECM Controlled exhaust brake on an 05 Auto

[sfpcservice]

Got a pacbrake PXRB installed on my 05 auto and have the ecm running it just like an 06 or 07 can do!

https://smartysupport.com/forums/to...-pxrb-pacbrake-and-on-board-air-installation/

Been driving on it for a few days now and it's one of the best mods I've done to the truck.

 

[Ozymandias]

Nice, good to hear that the 05 is also capable doin it.

 

[AH64ID]

Got a pacbrake PXRB installed on my 05 auto and have the ecm running it just like an 06 or 07 can do!

https://smartysupport.com/forums/to...-pxrb-pacbrake-and-on-board-air-installation/

Been driving on it for a few days now and it's one of the best mods I've done to the truck.

Okay, I'll bite... how do you activate the EB function in the ECM?

 

[sfpcservice]

Okay, I'll bite... how do you activate the EB function in the ECM?

Custom tuning...

 

[AEdelheit]

Very cool , I did not know that was an option for the 05's. I installed my first PXRB about 10 years ago and have had one ever since!

 

[sfpcservice]

Very cool , I did not know that was an option for the 05's. I installed my first PXRB about 10 years ago and have had one ever since!

It's not an available option, it has to activated through custom tuning...

 

[sfpcservice]

Got a demonstration video of the brake in action.

 

[AEdelheit]

It's not an available option, it has to activated through custom tuning...

Ya I noticed that part but did not know it was even possible with customer tuning so good to know!

 

[p-Bar]

very cool will this work on my 04.5 with my BD brake? enough ram in computer?

 

[sfpcservice]

very cool will this work on my 04.5 with my BD brake? enough ram in computer?

Should work fine. What are you using now to run that brake?

 

[Ozymandias]

04.5 has it already active, mine works fine with the Jacobs Brake.
https://www.google.com/url?q=https:...2ARgQFggNMAE&usg=AOvVaw1Ev0hI7vh3Brhecy8HNJgi

 

[p-Bar]

Ozy thanks very interesting. The 04.5 per jacobs back in the day said the 04.5 didn't have enough RAM in the computer for the "flash" and they were concerned about a thrust washer not being installed for the reverse torque of the brake. Well looking again at page 2 of the install manual is shows 04.5 and 05 N/A for the autos

 

[Ozymandias]

I know that they say it isn't for the Automatics, but that is for warranty reasons.
The interesting part is that the 04.5s ECM is by default ON* for the JB - but the 05s ECM is by default OFF.

*no programming or activating or anything else is needed, just plug the 2 pins into the ECM connectors and be done.

 

[Superdawg]

I know that they say it isn't for the Automatics, but that is for warranty reasons.
The interesting part is that the 04.5s ECM is by default ON* for the JB - but the 05s ECM is by default OFF.

*no programming or activating or anything else is needed, just plug the 2 pins into the ECM connectors and be done.

Ozy,
Sorry to drag up an old thread but this is interesting. It appears you started with a Jacobs then upgraded to a Pacbrake? If this is the case and so I am clear: For your O4.5 48re and the Pacbrake, as you slow down, does the Pacbrake shut off between downshifts then activate again in a lower gear by itself?

I have the 04.5 48re and the Pacbrake, using the supplied control box to operate the Pacbrake. It only works in the gear it activated on. As it slows down, the brake shuts off at a certain speed, depending on what gear it started in. My transmission has been rebuilt, valve body kit and lower stall torque converter 40k miles ago.

Happy New Year and a heartfelt thanks for your input to this forum for many years.

Thanks,

 

[p-Bar]

I had the BD in my 04.5 equiv to the PAC brake as they were only a block apart and probably poached each others employees. My trans was built all Goerend parts valvebody ect. .Didn't really notice it down shift by itself always had to do that manually.

 

[Superdawg]

To be more clear, I am asking Ozy if on his truck, will the 04.5 ECM will shut off the Pacbrake on slowing down, downshift and reactivate the Pacbrake in the next lower gear.

 

[Ozymandias]

Hi
Yes it has forced downshifts when the road speed decreases and it re-engages* the EB 4-3/3-2 is done and controlled by the ECM without input from you as a driver.
When I switched from JB to Pac all I did was changing the solenoid from vacuum to pressured air.
*it also re-locks the torque converter while doing so.

So you don't need the Pac Controller for an 04.5, all you need is a simple switch and a relay and two wires to the ECM.
Follow the install manual for the Jacob's brake which has a wiring schematic in it if you want to re-wire your installation. It is very simple made and no big deal.

Edit: it also downshifts/re-locks while on cruise downhill with the EB enabled and the given gear isn't capable of holding the set speed.

Edit 2: with the standard single disc converter it also commanded and tried to re-lock the converter but it would slip and one needed to feather the throttle for a second or so to help it a little. Now with the triple disc it just re-locks no matter what.

 

[Superdawg]

Wow. Sounds good. I am used to the feathering to get it to engage occasionally.

One more thing and maybe a downside to all this. With the forced downshifts, is it possible as you are slowing down via exhaust brake to a red light/stop sign/slow traffic, someone following behind you is not going to see your brake lights until you slow to about 15 mph?

 

[petersonj]

is it possible as you are slowing down via exhaust brake to a red light/stop sign/slow traffic, someone following behind you is not going to see your brake lights until you slow to about 15 mph?

Quite possible. I always glance at my mirrors to keep track of approaching vehicles from behind. The same on long mountain downgrades. I will just touch the brake pedal enough to activate the brake lights, if I need to get someone's attention. Over 460,000 miles and over 25 years of driving using an exhaust all of the time and I never had an incident.

- John

 

[AH64ID]

I’m actually surprised the exhaust brake doesn’t actuate the brake lights on these trucks. The manual activation of the trailer brake controller does, but not the exhaust brake.