About 1 out of every 15 times I try to start my crossfire, it won't start (even if I keep the key in the start position for 30 seconds). I can hear the engine turning over, however I don't believe the engine is flooding because if I remove the key and immediately try to start it again, the car will literally start in under 2 secs.

Any ideas?

Thanks.

 

sounds like an ecu glitch of some sort. when you remove the key and place it back into the ignition... it resets the cars ecu. hence the reason for starting the 2nd time around.

this would be my guess.


the crossfire has an electronic ignition with f.i. it wouldn't make sense to be flooding such as a carbureted car would do. but i'm no certified mechanic.

time to head to the dealer for a diagnostic.

 

I think I figured it out last night. Apparently the stereotypical "german engineering = simpler engineering = product usually works" equation doesn't hold up when it comes to MB engineering.
The battery in my key had enough juice to unlock the doors from about 20 feet, but not enough juice for the transponder to work while it's in the darn ignition. I'm buying american from now on.

 

I guess they didn't call that module the "SKREEM" for nothing!

 

I don't follow... how does the battery affect starting?

 

The key FOB is used for the keyless door locks and is also tied in with the starting circuit as part of a theft deterrent system. A dead FOB and the car will not start. The owners manual recommends changing the FOB batteries once a year to prevent such problems.

I have for lack of a better word, a dummy key, that I keep in my wallet in case I lock the FOB in the car. The dummy key will manually open the door. If you try to start the car with it, the engine turns over for less than a second and dies. The starter cycle needs the FOB to start the car.

 

Now that could be a valuable lesson - I had no idea the battery in the key could prevent starting.
I guess it would pay to have a spare battery in glove box or change out before it goes. It should give signs of wearing out before complete failure.

 

It's actually a pair of batteries, CR3032's if memory serves. You can get them for less than $5 each from just about anywhere. So the good side to this story is that if you did come up with a dead battery you could walk into just about any convenience store, grocery store or drug store and find them.

I always thought that it might be cool to do what BMW does and have the car re-charge the key-fob batteries while the key was inserted, but that would get really expensive when the batteries finally failed (all batteries fail. Its not if, it's when.) because the whole key fob would need replacement. I don't know what the BMW fob runs, but the Crossfire keys cost $180 + plus the cost of installation and I would imagine BMW's fob is in that ballpark.

 

That is assuming you are not stuck in the middle of nowhere.
Does that mean that if your batteries did fail during say a long road trip - the engine would just stall out or are they needed just for initial starting?

 

You'll know when it's going to cause you problems, because you'll start to loose the range you typically have to unlock your car doors. However, if you're like me, you might start trying to diagnose ignition failures before finding out that this "failure" is actually a "feature".

 

If my batteries have been in the FOB for much over a year, my first diagnostic step would be to put in a fresh set of batteries. I'm in the habit of swapping out batteries on the anniversary of the purchase date or there abouts, no problems so far. And as preventive maintenance, I faithfully change out the main car battery every three years... why wait for a dead battery?

 

The key "authenticates" itself to the car when the engine is started. It's kind of like the RFID systems in general use today but more secure because the car and the keys remember each other's secret password. From the service manual:

Connected to the Sentry Key Remote Entry Module (SKREEM) is a Sentry Key Antenna Ring which surrounds the ignition lock cylinder. When the ignition is switched on, the Sentry Key Antenna Ring is supplied with power. A data block is transmitted inductively via the Sentry Key Antenna Ring to the SKREEM and then on to the Powertrain Control Module. If the antenna ring data block content is invalid or if vehicle battery power is too low to build up enough power for the antenna ring, the Powertrain Control Module will not receive the proper signal. This is displayed with the message “Start Error” in the Instrument Cluster.

The SKREEM retains in memory the ID numbers of any ignition key transponder that is programmed into it. For added system security each SKREEM is programmed with a unique secret key code. This code is stored in memory, sent over the CAN (Controller Area Network) data bus to the PCM (Powertrain Control Module), and is encoded to the transponder of every ignition key that is programmed into the SKREEM.

 

Would a intermittent key fob already programmed to ignition cause issues? My understanding is that once initial programming is done, the skreem is done skreeming?

 

From what I understand, it's a challenge/response mechanism. A dead key fob battery would prevent the car from starting because it would not be able to respond to the car's challenge. In this case the car's CLP/SSM would believe that someone is trying to start the car with an unauthorized key and shut the ignition off. I guess this would be easy enough to test by trying to start the car with a key that has the batteries removed.

 

Here is the strange part, to the best of my knowledge, "start error" was never displayed in the instrument cluster. And from an engineering stand-point:
Why would they allow power to the starter in the case of a bad/improper signal? My engine was turning over, but getting no fuel. The first thought I would have if the engine wouldn't turn over would be either a dead battery or bad ignition signal. I'm just glad I figured this out before "poking around" in my engine bay.

 

Speaking of dead key fob batteries, I ran across this in the service manual:

The batteries in the Remote Keyless Entry transmitter can be tested by pressing and holding both the lock and unlock buttons simultaneously for more than one second. The batteries are charged sufficiently if the LED next to the ignition key blade lights up briefly.

A built-in battery checker. How cool is that? You can also change the way the car unlocks the doors when you press the button. Read on...

Global/Selective Central Locking

The keyless entry system has a Global or Selective mode function for central locking that can be programmed by the customer. The factory setting is Global, which will lock and unlock both doors, rear liftgate and fuel door centrally when the respective button is pressed once. The Selective mode will only change which power locks unlock. To activate the Selective mode, press both the Unlock and Lock buttons simultaneously for approximately five seconds until the battery check lamp in the transmitter flashes twice. The Unlock button will then only unlock the driver door and the fuel door when it is pressed once. Pressing the Unlock button a second time, unlocks the passenger’s door and the rear liftgate. The factory setting can be restored by pressing both the Unlock and Lock buttons simultaneously again for approximately five seconds until the battery check lamp in the transmitter flashes twice. If the vehicle was locked using the power lock switch in the center console while in the Selective mode, opening a door from inside unlocks that door only. If the vehicle was locked using the power lock switch in the center console while in the Global mode, opening a door from the inside unlocks both doors and the rear liftgate. If the vehicle was locked using the RKE transmitter, the doors and rear liftgate cannot be unlocked using the power lock switch in the center console. If the vehicle was locked from the outside, opening a door from the inside will not unlock other openings but it will trigger the alarm.

 

What installation cost are you referring to? The owners manual tells you how to program the key. Am I missing something (I usually am LOL)?

Good find, thanks. I looked through the "owners manual" and saw no reference to this feature.

 

It seems the key fob has several sequences when you reprogram it. Mine went into some kind of lock out mode with the first try - nothing worked I though it was maybe a weak battery but tried again with same results - finally i got it back to the original factory specs.

 

If you get a new key, the Dealership has to plug in the DRB-III and "introduce" the SKREEM and the key to each other. The system uses a two-way, two-factor cryptographic challenge.

I don't remember seeing this in the owner's manual either. Probably just an oversight on someone's part, albeit a somewhat important one.

 

i know this is an old thread but.
for what it is worth , i have taken the batteries out of the key fob
and my car will start ..