[rcroq17]

Hi! I have 2008 e90 335xi (manual) that is not starting. Power is on when i put the key in and everything but it would not start. I checked the battery and is good (even recharged it to be safe). I was about to start to replace the starter but i thought maybe i should get some insights here first. Im new to bmw world so im not entirely familiar with it. Im assuming maybe its electrical or computer module issue but just not sure. I would appreciate any suggestions on how to troubleshoot this issue. Thanks in advance!

Ill try to post a vid of how its doing when i tried to start it.

View post on imgur.com

[Chapperss]

Earth issue or maybe immobiliser? is my guess.

Though I`m sure the smart people will be along shortly and will give you a proper answer

[macloren]

If there's no noise like having a dead battery, most likely it is the starter.

[Antetokounmpo]

Check chassis ground first. You can connect the oil filter housing to the ground post using jumper cables.

[4 Doors]

Originally Posted by Antetokounmpo

Check chassis ground first. You can connect the oil filter housing to the ground post using jumper cables.

+1 check the ground

[dpaul]

So, since you are new to the BMW world, there are five main reasons why your car will fail to activate the starter:

1) the starter or solenoid is dead

2) the battery is old/weak

3) the ground strap between the engine block and chassis has corroded and failed.

4) the cable carrying current from battery to starter is corroded, most likely at the passthru where it leaves the bottom of the battery box. Often the result of water accumulating in the battery box

5) there is a problem with the CAS module, which is directly connected to the solenoid and activates it. This failure can be in CAS hardware or due to CAS failing to detect the clutch or brake pedal being depressed because of bad sensors/wires/connector at those pedals

Each of these possibilities is relatively easily checked. Batteries and starters are not inexpensive so it makes sense to test before blindly replacing components.

As several posters indicated, it's very easy to test the ground strap - use a jumper cable to bypass it by connecting one end to the engine block and the other to a clean chassis ground or the battery negative terminal if you can't find a good spot in the engine compartment.

You can use a jumper cable in an analogous fashion to bypass the lead from battery positive terminal to jumper terminal in the engine compartment.

Battery of course should have resting voltage above 12, preferably close to 12.6. The car may start with less but if it is less, the battery is not in good shape. Battery can always be removed and taken to an Autozone or similar parts house which generally can do a load test for free.

Testing the starter/solenoid is a little more involved because you have to remove airfilter to get better access or intake manifold to get best access. At that point, put 12v on the terminal that the small diameter wire goes to.

If all that checks out, you've got a CAS problem.

[E92_William]

Get a broom stick and hit the starter motor and solenoid. This is common starter failure mode. Mine failed right after coding my battery and made no noise or click