How do I reset my security system?

As an update to a previous post/question.
I have since replaced my fuel pump and filter, but this did not help.


I have a 1998 ML320 with 150K miles.

Has worked great everyday until now.
Upon leaving work battery was dead, just click click when I tried to start.
I replaced the battery, and now it will almost start and then die, every time.

I can hear it fire at first, and then it instantly dies, like no fire.

A service manager told me he was pretty sure that my key needs to be reprogrammed.
He says 1998 ML320's had a problem where the key would loose programming sometimes if the car battery went down.
He told me the key sends out rf signals that must be recieved by the cars computer inorder for the car to continue running.
That the key is not simply a cut key, but that the rf must be recieved.
He mentioned for me to try holding the remotes unarm button while pressing the arm buttin five times, and then insert key and try to start it.
That this might reprogram it.

This did not help me.
Even with fresh batteries, actually instead of this helping, since doing what he mentioned (or maybe it was my changing out the remote batteries), now the car's alarm remote does not even unlock/lock the doors remotely.


All suggestions are greatly appreciated.

How do I reset my security system?
Does this RF signal coming from the alarm remote and recieved by the car sound familiar?
Thanks in advance for suggestions/advice.
I'm really wishing to get this back on the road.

Regards, Ben

 

Hi,
This sounds familiar. Did I not reply once before?
The key handshakes with the ignition switch (EIS) once it is inserted using radio frequency (RF or IR). This is one level of several security systems.
If indeed the car cranks and tries to start I don't believe it is this handshake that is at fault since the car wouldn't crank if the handshake didn't occur.
However it is possible although I'm guessing that the EIS itself is faulty and therefore does not send the correct signal to the various circuits that take part in the start procedure. I assume your vehicle has the sequential start regime. Turn the key and the system does the rest. i.e. You don't have to keep the key turned.
The EIS turns on a number of different circuits dependent upon switch position.
If indeed the EIS is OK then I would go for fuel relay. However why would you have such problems after a changed battery.

You are sure you have a good main battery? Is it a new one or did you just recharge?
Once batteries have gone below 12.5 volt they never work the same again due to internal non reversible chemical change.
When you crank with the headlamps on these remain bright. Yes?

Have you tried disconnect the main battery, leave for 30 mins (don't really have to wait this long) then reconnect. Since the problem occurred after a dead battery is does suggest a memory reset issue however.

Next suspect in the chain after all above OK would be the electrical connections, fuse, fuse box etc to the pump. Corroded connection.
Let us know how you get on.
I'm sure Sleepwalker will come up with something!!

 

Thanks.

Yes, I have a brand new big bosch battery. Since this problem, I have I kept it disconnected unless I'm trying to crank the engine.

yes lights remain bright while cranking.
Starter turns over nicely, and engine instantly starts as it always has, and then it sounds like it has been told to turn off, and turns off. no sputtering or missfiring or weird stuff

I cheaked every fuse in the fuse box.
I have not tested any relays. Not sure how to do this.
I was thinking perhaps I should just replace any that relate to this matter.

Yes I have the sequential start regime.
Yes the car starts for a second and then looses fire or fuel.

I see the plugs are sparking atleast while the engine is running.
I have a fuel pressure tester.
I also checked the error codes.
It showed no "trouble codes"
but had two "pending codes"
pending codes were:
P0700 = transmission, trransmission control system, control system malfunction.
P0720 = output speed sensor, speed sensor circuit, circuit malfunction.

I'm not sure what to think about these pending codes, except there related to the transmission and my non-knowleagable first thought is that there not related to this problem i'm currently having.

All suggestions on this are appreciated.

Does "pending" mean not as bad as "trouble"?,


I would gladly replace any small cheap components to reduce posibilities through process of elimination.


Thanks greatly, Ben

 

After taking it to the dealer, this is what they propose:

All opinions on any possible cheaper options or agreement on this option are appreciated.
My initial opinion is that's alot of stuff going bad all at the same time.
The car ran fine up until i parked it. Came back from work and the battery was dead.

$126 Buy new key (everyone has recommended trying this first)
$268 Buy new AM module "key control module" (I was told by another dealer that this might simply be reprogramable)
$180 Ignition switch/sensor
$450 labor


What do you guys think?
I'm told them to go forward with it since I already spent $230 in tow fees.
Otherwise I would pay them $118 for diagnosis and then more towing to to take it to foreign repair shop, and then etc.etc.

Since I can't even get a manual, it would be a disaster for me to try to work on it myself.

Anybody know how I can get a manual, for future issues????

 

The garage are changing lots of things at once. Not a very professional approach especially since there are things that they are NOT doing which may well be the cause and cost bery little to correct. I guess they this may fix the problem but at a cost.
If the car cranks I would be VERY surprised if the key has anything to do with it. Since the handshake MUST BE established to crank the engine howevr maybe it requires a regular ongoing handshake in which case it COULD be the problem.
I've given you my best shot. EIS or fuel pump relay. The fuel pump relay is NOT on your list however.
I have however thought of something else now you have clarified the problem.
Since the engine starts but fails to keep running how about the oil pressure switch.
Simple and cheap to fix!
The fuel pump relies on a relay being energised to keep the pump running. This is why I suggested the relay in the first place. However if there is no oil pressure or alternatively the switch is faulty (or the connection to it loose/corroded) then the relay doesn't remain energised and the motor stops. This is a safety feature.
The very same relay is initially energised by a temporary feed from the ignition switch but once the engine starts this feed is cut.
This should be quite straightforward for the garage to confirm. You just temporarily ground the switch (negating the safety feature whilst a test is made)
Looks like they want to raise some money at your expense or just aren't very competent.
Keep us posted.
Stuart

 

I am having the same problem you are having. Car starts and dies right away. Fule shuts off. My dash keeps saying "calculating, please wait..." and it shows the picture of a key. I bought a brand new key and did not solve the problem. I left the key in the ignition for days and nothing happened. Anyone know what it could be?

 

I am having a similar problem....most times, cranks but no start, the only time I got it to start is when I reset the security system with the key in the manual and it started....yeah....but as soon as I put in gear, died....booo. So today it is getting towed....bought the vehicle not running. Had been to two mechanics, first one said was security problem and second said replace spark plugs first (gas soaked), then more repairs. So off to the repair shop. I will let you know of the outcome.

 

any updates on the possible cause. i am having a similar problem with my ml320 i shipped overseas with the battery disconnected.

 

I don't have an answer yet, I see the other posts where from years ago. I bought my car from a friend not running. I know there is a key in the manual and it is suppose to reset it. and have read that the key looses programing when the battery is disconnected or drained. Mine is at the shop now. I was unable to get it to work. both of the keys I was given had no or dead batteries in them. you can reprogram the remote, it is the manual how to do it. I will get back to you when mine is finished.

 

my 98 320 ml takes forever to start andwhen it does it dies soon after then wont start for hour or more