2007 Tahoe 5.3l AFM DOD delete thread

[Geotrash]

I seriously doubt a small intake leak or any tune parameters are going to trigger the service brake message. Fixing an intake leak will make it run better though. It will lope a little more with a bigger cam, so maybe that is what you are feeling, @Geotrash could confirm or dispel this last idea though. Also, with tuning, it is all about the skill of the guy filling in the boxes.

There were a few threads a while back on the service brake message, one turned out to be a simple low fluid level, but the other had something to do with a bad O-Ring in the vacuum booster assembly. My search skills are poor, but you might try finding that one.

I think one thing you might try to help in diagnosing the issue is not think about the cam swap when you are thinking about the brake issue. It likely is just a coincidence it happened shortly after the cam swap. It could be related, but the odds are a lot greater it is something else.

It's interesting timing, but I haven't driven my cammed truck in a few weeks, but did drive it today. As I was backing out of the driveway and hit the brake, it felt like my brake pedal was skittering like the ABS had been activated. And thinking back on it, I remember feeling it a couple of other times since the cam swap but I dismissed it. No lights or codes though. I'm wondering if it's something about the lope of the cam varying the intake vacuum in such a way that it's either making the brake pedal feel like the ABS is being triggered, or perhaps it actually *is* being triggered somehow. I would need to learn more about the details of how the ABS system gets its signals to activate to see if the latter hypothesis holds water.

 

[ShootinHeavies]

I seriously doubt a small intake leak or any tune parameters are going to trigger the service brake message. Fixing an intake leak will make it run better though. It will lope a little more with a bigger cam, so maybe that is what you are feeling, @Geotrash could confirm or dispel this last idea though. Also, with tuning, it is all about the skill of the guy filling in the boxes.

There were a few threads a while back on the service brake message, one turned out to be a simple low fluid level, but the other had something to do with a bad O-Ring in the vacuum booster assembly. My search skills are poor, but you might try finding that one.

I think one thing you might try to help in diagnosing the issue is not think about the cam swap when you are thinking about the brake issue. It likely is just a coincidence it happened shortly after the cam swap. It could be related, but the odds are a lot greater it is something else.

I have a crew 06 5.3 thats running a TSP chop monster and all supporting mods, so what it feels like isnt the cam. I am looking at anything other than the cam now, just really strange timing for this. But we are gonna get into it further this weekend and see.

The shop that tuned the Tahoe tuned my 06 several years ago when I installed it, I just didn't have the time to do this swap and had them do it instead.
They do quite a few of these, and other associated mods, so I dont know if its the tune either.

 

[ShootinHeavies]

It's interesting timing, but I haven't driven my cammed truck in a few weeks, but did drive it today. As I was backing out of the driveway and hit the brake, it felt like my brake pedal was skittering like the ABS had been activated. And thinking back on it, I remember feeling it a couple of other times since the cam swap but I dismissed it. No lights or codes though. I'm wondering if it's something about the lope of the cam varying the intake vacuum in such a way that it's either making the brake pedal feel like the ABS is being triggered, or perhaps it actually *is* being triggered somehow. I would need to learn more about the details of how the ABS system gets its signals to activate to see if the latter hypothesis holds water.

This is exactly whats happening when it triggers the message, and its very random. Otherwise it runs great and functions normally.

 

[Geotrash]

This is exactly whats happening when it triggers the message, and its very random. Otherwise it runs great and functions normally.

Same - it's totally random on mine too. The only difference is I'm not getting any messages.

 

[wsteele]

It's interesting timing, but I haven't driven my cammed truck in a few weeks, but did drive it today. As I was backing out of the driveway and hit the brake, it felt like my brake pedal was skittering like the ABS had been activated. And thinking back on it, I remember feeling it a couple of other times since the cam swap but I dismissed it. No lights or codes though. I'm wondering if it's something about the lope of the cam varying the intake vacuum in such a way that it's either making the brake pedal feel like the ABS is being triggered, or perhaps it actually *is* being triggered somehow. I would need to learn more about the details of how the ABS system gets its signals to activate to see if the latter hypothesis holds water.

The plot thickens.

Was the Denali you added that cam to a DoD engine (couldn't remember)? If so, did you do anything with the AFM sensor on the Brake Booster?

 

[ShootinHeavies]

Same - it's totally random on mine too. The only difference is I'm not getting any messages.

So we got into it a bit Sunday, replaced bad intake gaskets. The vacuum gauge reads 9-10 at idle of 670 rpm which jumps from 575-670 rpm, the gauge reads 10-14 at 800 rpm and 12 on the MAP sensor VIA snap on unit, seems vacuum is really low

 

[Geotrash]

The plot thickens.

Was the Denali you added that cam to a DoD engine (couldn't remember)? If so, did you do anything with the AFM sensor on the Brake Booster?

Yes it was, and no, I did not. Hmmmm…

What, if anything, should I do with it?

 

[wsteele]

Yes it was, and no, I did not. Hmmmm…

What, if anything, should I do with it?

Your guess is as good as mine. I only discovered it was there when I started to dig into this thread.

I honestly think if it was the source of the problem, it would be flagged as something to attend to when doing the delete. I mean, a lot of these have been done by now.

But then again…

 

[Just Fishing]

When i did the dod delete on my 5.3, i got weird errors the first startup
stabiltrack errors, brake errors, etc.
super weird.
Found two things.
First when i did the dod delete, i needed to turn off errors for the DOD sensors in the tune.
Then i had a reduced power message related to me cleaning the throttle body, I did the learn via tech2 to resolve.

 

[swathdiver]

So we got into it a bit Sunday, replaced bad intake gaskets. The vacuum gauge reads 9-10 at idle of 670 rpm which jumps from 575-670 rpm, the gauge reads 10-14 at 800 rpm and 12 on the MAP sensor VIA snap on unit, seems vacuum is really low

That's not enough to operate the brake booster. You need at least 18 inches of vacuum in my experience. I just checked my shop manual and the computer converts the vacuum signal to voltage so I don't know the exact specs for our trucks. If the camshaft turns out to be the problem and you desire to keep it, you might look into a hydroboost conversion.