F355 flat battery - jump start does not work

Visually inspect the battery connections and see if the remote posts are actually connected to the battery correctly first.

Jump starting these cars with another car is not recommended. I would verify the connection of the posts and correctly charge the battery and/ or get a new battery

 

if the rear connection isnt live it isn't connected to the battery properly or the battery itself is completely knackered. As mentioned, that means either the connections to the battery itself, inside the front RHS wheel arch or the cut off switch under the front boot lid.
The alarm doesnt disconnect this.

 

I jumped mine and blew my air bag ecu now my air bag light is on. Charge it full and buy a tender or go buy a new fully charged battery and install it. It's a cheaper fix than the $1200 air bag ecu it's not worth the risk. I wish I would have found this out before I jumped the car,,could have saved some time and money. Now I have a fully charged optima gel battery

 

I'd also recommend charging directly at the battery. I let mine die tried to trickle charge it from the engine bay and it acted weird because it was trying to send power through the entire system on a very low current. So I pulled the wheel put the pigtail connector directly on the batter then ran it up through the compartment underneath the hood where the "off" switch is. Switch that to "off" plug in a trickle charger if after a couple days it doesn't go green it's time for a new battery.

If it does go green you are good to go and you have easy access to hook up the trickle charge for future use. Anytime the car sits for more than 2 weeks I'd recommend putting the charger on it. All of these cars seem to put some sort of constant draw on the battery. My friend has the same problem on his elise I think it has to do with the immobilizer but that's speculation. If you take these steps you should be in good shape and prevent yourself from having to buy a new battery.

I posted when I had a similar problem and didn't even realize the battery was behind the wheel until after I read the manual and others here confirmed it. It's a rather odd location for a battery but there are reasons for it's placement.

 

Cycle your off/on switch under the trunk lid.

 

One other trick is to lock and unlock the car with the remote a few times if it won't start during a jump. Evidently, early car alarm systems could be thwarted by just disconnecting the battery momentarily. Using the fob to lock and unlock the system a few times lets the system know that you have the fob. I just recently went through this with my 355 and it was no fun. I was told that once the battery has gone dead, even if you are able to recharge it, it may not be reliable. My car had a Battery Tender cable preconnected to the battery and located in the boot, but I didn't have a trickle charger and the storage site where I had the car didn't have an electrical supply. The car died in about a week without being charged. I bought an Optima Redtop 34R and it fit fine in the battery compartment. Both the Optima and the Diehard gold or platinum models have about 1000 cranking amps. Interestingly, neither Optima or Sears websites could recommend a battery for the 355. The old battery that I removed was an Interstate 34R. (R for "reverse terminals). That battery measured 7h, 7w, 11long. I went to my local PepBoys and bought the Optima, which Was about $200.00! You may be aware, but the battery location (in front of the right front wheel) requires removal of the wheel. I actually had to buy a racing jack in order to get under this low slung vehicle. These cars evidently drain a battery very quickly, so the moral of the story is to remotely wire a trickle charger to your battery and use it regularly.

 

Even after you correct the battery situation, locking and unlocking the car via the fob let's the alarm system know you are not a thief and will enable a start.

 

Yes by all means double check the battery connections. Mine came loose in a left hand turn at the end of my third real drive after it was delivered here from out of state. Hard to believe but the cables were farged-up by some "testadura!" >( It has a red top Optima battery and it looks like someone at the dealership tried to use the front terminals and also twisted the cable fuse a couple times. The plastic threaded cover was completely loose. That mean about 4 to 6 turns loose! I think the only victim was my Alpine head unit IF it didn't just deactivate because of loss of power. Car is at the shop getting major done. We'll see if they can check this too. Battery cut off knob works great and I've driven it reliably about 4 times even over the winter since I fixed it.

 

For the record, I've never had an issue jump-starting my 355 with the aid of a battery pack (not connected to another car).

* Turn battery cut-off switch back on
* Connect battery pack in engine bay
* Turn pack on
* Toggle immobiliser using fob
* Start engine

 

Just wondering, if the battery cut off switch is used does this guarantee there will be no drain on the battery? Logic seems to suggest that is the case but thought I would ask anyway. If so, why use a battery tender?

 

No Because just sitting there the battery can lose charge and still die.

If it's cold out it will kill the battery as well even if it's disconnected at the terminals it can still die.

 

My experience of storing cars for 6 months months through winter since 1985 is that, if diconnected, a good battery will hold its charge no problem.