Anybody here know what the actual memory technology in this generation of cars is? EEPROM perhaps? I've read that many codes get reset when the battery goes dead which would suggest there's a volatile section. Just SRAM for that stuff? And then of course there's mileage which is never lost but still must be changed.

Curious as to how this all breaks down as I'm dealing with a dealer right now who swears they never touched stuff that obviously disappeared after some work was done. I think the battery went dead while they had it for almost a month. I cautioned them about it but I think they should know better anyway. Even when my battery had gotten down to where the motor wouldn't turn over, I never lost anything in 14 years. I do know when I picked it up, they'd left the battery compartment door open so clearly they did something back there.

 

What disappeared?

 

All four of my fresh new (August) TPM's went to zero, my Active Handling modes (e.g. Competitive Driving) vanished, my MPG went to single digits, my Range measurements were way low for half a tank of gas, and I had a setting on my audio for SiriusXM that accessed my iPod through some module that I bought years ago that disappeared. Also the passenger button to roll up the window stopped working. Down works OK. Maybe that is just the switch that is faulty, but it's a new condition.

All the real time stuff, temperature, oil pressure is OK.

For what it's worth, this is a 2007 Z06.

 

Did this stuff clear up or is it ongoing?

 

It's at the dealers to be cleared up. What I expect is they will say it is not their fault.

They fixed an airbag problem after a month, and on Friday I checked that that fix was OK, and I drove it home. That is when I discovered the mess and by then the day was done.

I guess my mistake is not checking that they didn't break something completely unrelated to what they were tasked. Drove it back this morning, Monday, it is there now.

Basically, the thrust of my memory question is: could these memory changes have occurred without the intervention of either a power disruption or a tech?

The onboard system, wouldn't, and I would like to prove, couldn't have done this by itself. The fault has to have been introduced externally.

Most tellingly I think, is that the SirusXM setting disappearing is not something the computer could have done, it doesn't have that authority in its software. It's a factory or dealer setting.

Same with the TPM's. Can the computer program decide to start reporting all tire pressures as zero? I expect they will just shrug, not their fault.

I think I'm screwed. I don't have a good logical reason why what happened could only have happened while it was in their possession.

 

Disconnect the battery for about 15 mins, reconnect it, index the windows, then go drive the car for about 5 mins to make sure you have everything back working.

Hence when modules get under 12 volts from battery going dead, they glitch like hell, and doing the battery disconnect,wait, then reconnect, reboots the modules to solve a lot of the low voltage glitch problems.

If you do have a tech II, then go in ad delete the Dtc stored history of the car, since the low voltage cause a lot of DTC to fault as well. If not, have the dealer clear the DTC history with there Tech II, caused by the battery going dead instead.

Side note, quick way to get a hell of a discount on a used C6 from a dealer if you have your own tech II.
We all know that the C6 will run down the battery in a mater of weeks when just sitting on the lot not on a tender, someone is going to try to start the car with the battery way down on voltage and starter will just click, this will cause a hand full of DTC codes since it going to under voltage the Modules, they will use a jumper pack to start the car, and if you can put a tech II on the car during your test drive, History DTC codes will look like a laundry list of items before the service shop can put a tech II on the car to delete them from the dead battery module glitches in the first place.

 

The only thing that should be lost when the battery dies or is disconnected is the window indexing and even that depends on where they were left. IIRC the indexing will still be fine if the windows are all the way up when the power is interrupted. Should not lose any radio settings or other personalization. TPMS should not be affected. No idea about the ipod module since that's obviously some 3rd party add on.

 

Pretty much guaranteed they would have disconnected the battery and not made any attempt to plug in anything to retain power if the were working on the air bag system. They're not that stupid. As far as the TPMS system is concerned, my direct experience is that it polls the sensors pretty much when you start the car so that you don't drive off on a tire that's lost pressure say overnight. If the sensors are all still reporting zero, clearly something is not right. How good is the battery in your car. C6s sure don't like marginal batteries.

 

Of course not

Short answer is: no

Here's a guess:

They had the car for a month, and during that time they took it for a few test drives to make sure the rev limiter was working OK. That's where the single digit MPG comes from. On one or more of these the battery was dead and they jumped it to start, as evidenced by the open battery compartment. That's when the low/no voltage happened.

 

Fats: So far as I understood, a special electronic tool is required to register each TPM against the computer. I don't have such so that is something that I will have to leave up to them. Not sure if the air bag explosives can be disabled for work but I sure wouldn't want my head in there if there wasn't a way to safe the system

Which would suggest that that data is kept in a non-volatile memory type, like EEPROM.

I think what happened is the battery did go dead where the car was parked until I could pick it up. I called them earlier asking them to make sure the car would start when I came by. It probably didn't so they jump started it and then walked away, not checking that everything was still OK. That's my best hypothesis. The car did drive OK when I picked it up and drove home. No limp mode.

That's what I think.


Thanks guys. I'm normally on the C3 forum but you all appear to be just as helpful as that bunch.
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About the TPMS sensors. The car shouldn't 'forget' sensors which were programmed, unless of course they replaced the RCDLR. Yes, you may need a special tool to register the senors with the car. They're about $10 from amazon. Some model years had sensors which could be registered by simply causing a pressure drop while in program mode. Also, IIRC, if a sensor is not registered or the sensor can't be read, you get 'xx' or 'xxx' as a reading, not 0. Are / were your sensors reporting 'xx' or 0?

 

I tried the pressure drop on one wheel just to see if that would work, and it didn't. But I don't know what program mode is. Evidently the car needs something more when changing pressures.

Funny thing about "XXX" vs "000", I kept wondering why I wasn't getting the yellow skid alert with '000' registering on my tire pressures. And then on the way to the dealers yesterday, the '000' changed to 'XXX' on all fours, and the alert showed up for no good reason that I can understand. Just out of the blue!

Have a C8 on order and want everything working before I try to sell the car.

I think what happened is they never thought to look and see what else happened after fixing the air bags and/or jump starting the car.

I will report what they tell me, this is one more educational experience I don't want.

 

Since you don't know about program mode.

In order to register the sensors with the car, the car needs to be in 'learn' mode. For earlier green sensors, the pressure drop method will work. Mid 2010 there was a switch to black sensors and a programming tool is needed.
1. Use the start button to get into accessory mode. The yellow light should be on.
2. Press both the lock and unlock buttons on the fob at the same time until the horn beeps.
3. Start with the LF wheel and either drop the pressure quickly by at least 5 lbs or if using the tool, touch it against the sidewall at the base of the valve stem. If the sensor registers the horn should beep. Some instructions say to touch the top of the valve stem with the tool pointed down.
4. Proceed clockwise with the same method RF, RR, and LR. The horn should beep once for each sensor except for the final sensor where it should beep twice.
5. You're done. Exit accessory mode and adjust tire pressures as needed.

Some hints. If you are doing pressure drop, air each tire up to 38 pounds first. Then before you start, remove all the valve stem caps.
If you don't get the first sensor programmed within 1 minute the procedure will time out and exit learn mode.

 

You sound like an expert at this. thanks Ian

 

Thanks everybody for all the help. I learned a lot about C6's that I didn't know. At this point I feel a bit more empowered.

As for the dealer, it was a non-event. The service adviser listened to me, followed up with the techs, and agreed that they had simply forgotten to re-initialize the computer before I picked it up. No charge and out the door I went. No back and forth needed. Good to leave a pat on the back and a few stars for the advisers in on-line service comments, this was Boardwalk Chevrolet in Redwood City.