Start with simple things first. Make sure the negative and positive post are fully tightened. When I just press fit the negative post on the battery, I had the same issue where the interior functions would work but not starting.

There is a real possibility your key or EWS system has broken down.
There's a cheap $10 tool you can buy, it's like a red plastic ring and it will tell you if your key or pick-up coil is the problem. Good to check with this tool before making further assumptions.
Search ebay for 'EZS EIS coil check Checker Immobiliser System Fast Easy for Mercedes BMW AUDI'

I reprogrammed my broken EWS and new keys with an ebay tool called AK90+ .

It's true. Maybe not all E53s. But mine 2006 X5, when I went to Sears and replaced the battery, they could not start the car. For my car (again, maybe things changed in 2006), I needed to replace the same exact battery or else the EPU needs to be reprogrammed.

Sounds like they pulled your leg. There is nothing battery related coding on any E53.

+1 - no E53 (of any year) has the computer bus used by BMWs IBS. Sadly, it seems that many E53 owners are told they need the battery to be coded when in fact there is zero coding required or possible.

If you have an issue after a battery change, it is something else....

This is interesting. If it is something else then someone explain to me why they couldn't get the car to start at Sears after replacing the battery with the Sears battery. The lights came on and everything, but the car would not start.

There is something there. I have no idea what, but I didn't imagine it.

Must have been something simple like drained battery (even if new) or poor terminal connection if you mean that the engine didn't crank with the new battery. If you mean that engine cranked normally but did not start it must have had lost EWS sync (caused by previous start with poor battery) which was rectified with diagnostics.

A few possibilities are factory defect battery or a loose internal contact in the BST that was separated when the sears battery was installed and coincidentally closed by chance when the replacement was installed.

car will not “not start” from battery not paired to car with the 08 and newer intelligent battery. (It is pretty cool I replaced battery in customers 08 328xi and the details are great on that system ).

Example: it keeps a history of how many hours at what battery percent charged. (At replacement the old battery spent a lot of time at 40% or less charge).

Tried original key and spare key. Charged battery to 12.8 volts. Checked fuses in back. Will check fuses in the front in the morning. Still no crank, no start, no moan, no nothing.

Voltage at B+ jump point under the hood?


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Symptoms match BST opened. See if the car will start with a jump start. Actually you can self-jump-start with a long enough jumper cable: jump from the positive battery terminal to the B+ under the hood. If it starts the BST is open. You can get a repair kit but a lot of people will get a full cable from a junk yard


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