DIC and factory radio connected thru vehicle computer?

Steve-B · Jun 12, 2015

This may be a stupid question, but how interconnected are the DIC and factory radio? Or are they at all?
I've been having an intermittent problem with my radio: Almost every time I start my truck (with the radio on) it sounds like either one front speaker is not working, or the bass has dropped out. Usually it comes back after a time and sounds pretty good. This has been going on for several months, and I had resigned myself to having to put up with it because I just didn't want to spend the money to get it fixed. However, another problem has cropped up. Many times I'll be driving along, look down, and see a "check tire pressure" message in the DIC. Usually it's the left rear, but sometimes it shows two tires (and on occasion, all four). I go thru the menu and check them and they are all within 1 or 2 psi of each other, and none are "low."
The reason I ask if the two are interconnected is that on the rare occasion that the radio is working properly at startup, I don't get the tire pressure warnings. I have only noticed this occurrence once or twice in the last week or so. I'm going to try to pay close attention in the future to see if the same thing happens consistently.
My concern is that this is all a prelude to a catastrophic failure in the vehicle computer.

half-breed · Jun 12, 2015

What year avalanche?

redheadedrod · Jun 13, 2015

What year?

I know with the 2003-2006 they both are... They use the Class 2 Databus to communicate. Your Dash gets all of its numbers through the databus as well as the DIC display. The radio also gets its information for the speed (for auto volume) and RAP (Retained Accessory power) as well as steering wheel controls if you have them. The radio also communicates with the XM radio with the class 2 Dataline and I recently found out only the LUX (y91 option) amplifiers also talk over the databus. (The standard one in our avalanches is just a regular amplifier.)

Rodney

Steve-B · Jun 15, 2015

Need4Speed said:
What year avalanche?

2007 LT

redheadedrod said:
I know with the 2003-2006 they both are...

Opinions about a forthcoming failure of the vehicle computer?
If it has any bearing, I've got just under 97,000 miles on my truck.

Snyder80 · Jun 15, 2015

I can't comment on a computer failure coming... (As a side note there are multiple computers in the truck. There's a body control module and a power train control. Possibly a separate transmission control)

But when you say a speaker "drops out" is it your passenger front? I ask because the TPMS is controlled by the passenger door module (the box with window and lock switches).

You might have an issue with wiring in that door getting pinched or a loose connection. Next time it does it, see if the window operates and the mirror moves

I could be way off but something to try

Steve-B · Jun 15, 2015

Snyder80 said:
But when you say a speaker "drops out" is it your passenger front? I ask because the TPMS is controlled by the passenger door module (the box with window and lock switches).

You might have an issue with wiring in that door getting pinched or a loose connection. Next time it does it, see if the window operates and the mirror moves

I definitely did not know this, but I have not had any issues with window or mirror on that side. But I haven't thought to try them when I get the tire pressure message. I'll try to remember to try them next time it happens. Also, I characterized the sound event as a speaker dropping out because I didn't know how else to say it. I lose most of the bass when this happens.

Snyder80 · Jun 15, 2015

do you have a tweeter in your front pillars? (Small speaker in the posts just above the dashboard? Those provide the "high" sounds and your door speaker provides the mids and lows. The tweeter would not stop as it splits in the dash before going to the door. This could give the sensation of "losing bass" if all you hear are highs from your right side

Steve-B · Jun 15, 2015

Snyder80 said:
do you have a tweeter in your front pillars? (Small speaker in the posts just above the dashboard? Those provide the "high" sounds and your door speaker provides the mids and lows. The tweeter would not stop as it splits in the dash before going to the door. This could give the sensation of "losing bass" if all you hear are highs from your right side

I was wondering what those things were. That's good information. Thanks!
That may be the basis of my whole problem, then. When the bass comes back, it sounds to me like it's on that side of the cab.

redheadedrod · Jun 16, 2015

What luxury features does your truck have? Do you have rear seat audio? Over head DVD?

What kind of radio do you have?

Almost sounding like your radio is having issues and it is throwing noise on the databus if your air pressure truly is fine.

Does the 2007 have any way of checking the TPMS sensor batteries? You may get false readings if the batteries are close to dying too..

If you have an onboard Amplifier it could be going bad too... Only way to know for sure is to bypass the amplifier.

If you can feed your speakers directly from your deck this would be one way to test the amplifier. I do not know if the 2007 uses a databus to talk to the amplifier or not assuming it has one. I THOUGHT the '03-'06 did but while looking through the information I have to splice into the wires to add an amplifier I found out otherwise.. Would be EASY to swap out the amplifer for an aftermarket unit in my '03.

Steve-B · Jun 16, 2015

redheadedrod said:
What luxury features does your truck have? Do you have rear seat audio? Over head DVD?

What kind of radio do you have?

Almost sounding like your radio is having issues and it is throwing noise on the databus if your air pressure truly is fine.

Does the 2007 have any way of checking the TPMS sensor batteries? You may get false readings if the batteries are close to dying too..

If you have an onboard Amplifier it could be going bad too... Only way to know for sure is to bypass the amplifier.

If you can feed your speakers directly from your deck this would be one way to test the amplifier. I do not know if the 2007 uses a databus to talk to the amplifier or not assuming it has one. I THOUGHT the '03-'06 did but while looking through the information I have to splice into the wires to add an amplifier I found out otherwise.. Would be EASY to swap out the amplifer for an aftermarket unit in my '03.

No real luxury features - no DVD; if you mean rear seat audio controls, then no on that count, too.
Factory radio with in-dash CD changer.
How do I determine whether I can check the TPMS batteries? That's a new one on me.
The only amplifier that I might have is the factory one (if one exists at all).

redheadedrod · Jun 16, 2015

How old are the sensors? If they are the original ones then it is quite possible they have dead batteries. They have simple watch batteries and I have been told they last about 5 years of normal use.

If you can't pull the battery life on your truck then it is likely a dealer diagnostic issue if even they can tell...

But if they are the original sensors for an '07 then I would have to say they are likely past their intended life span unless someone else knows different.

As to the speakers... It is more likely you have a bad speaker or two... You should pull the door panels and inspect your speakers for damage and make sure they atleast are all in one piece. Another user on here showed pictures where his BOSE speakers had all come apart at the surround.

Rodney

Steve-B · Jun 17, 2015

redheadedrod said:
How old are the sensors? If they are the original ones then it is quite possible they have dead batteries. They have simple watch batteries and I have been told they last about 5 years of normal use.

If you can't pull the battery life on your truck then it is likely a dealer diagnostic issue if even they can tell...

But if they are the original sensors for an '07 then I would have to say they are likely past their intended life span unless someone else knows different.

As to the speakers... It is more likely you have a bad speaker or two... You should pull the door panels and inspect your speakers for damage and make sure they atleast are all in one piece. Another user on here showed pictures where his BOSE speakers had all come apart at the surround.

Rodney

Sensors are original with the truck (2007). How do I "pull the battery life?" However, they still read pressure so they must still be working. The issue I'm having is the DIC telling me I have low pressure on various tires and they turn out to be OK.

Visually checking the speakers will have to wait for now. I've got a lot of work to do around the house.

redheadedrod · Jun 17, 2015

Steve-B said:
Sensors are original with the truck (2007). How do I "pull the battery life?" However, they still read pressure so they must still be working. The issue I'm having is the DIC telling me I have low pressure on various tires and they turn out to be OK.

Visually checking the speakers will have to wait for now. I've got a lot of work to do around the house.

Visual inspection of the problem speaker will likely take all of a half hour or less... Just depends on how good you are at pulling off the door panel. It really doesn't take long.

I would not be surprised if your pressure sensor batteries are very low. I am not familiar with how the OEM sensors work but at 8+ years you have gotten pretty good battery life out of them. Too bad they don't have them self recharge but I guess the sensors in them also go bad and it just makes sense to replace them when they start giving strange readings etc.

Again unless someone else knows differently...

Rodney