[mj6234]

OK, need some additional input. Car is a 2008 335i. Had 30BB, got the defective MOSFET replaced and reinstalled the ECU. Also replaced coils/plugs.

The car cranks but never starts. Before removing the ECU, the battery was disconnected. After the MOSFET was replaced, the ECU was reinstalled then the battery was reconnected.

There are no codes stored, which makes me think the repair was successful. Before clearing the codes immediately had 30BB come back.

Please tell me I am missing something simple here. Is there some step that needs to be done after the battery is disconnected? The guy working on my car disconnected and reconnected the ECU, so everything looks seated well.

[Mike@N54Tuning.com]

Originally Posted by mj6234

OK, need some additional input. Car is a 2008 335i. Had 30BB, got the defective MOSFET replaced and reinstalled the ECU. Also replaced coils/plugs.

The car cranks but never starts. Before removing the ECU, the battery was disconnected. After the MOSFET was replaced, the ECU was reinstalled then the battery was reconnected.

There are no codes stored, which makes me think the repair was successful. Before clearing the codes immediately had 30BB come back.

Please tell me I am missing something simple here. Is there some step that needs to be done after the battery is disconnected? The guy working on my car disconnected and reconnected the ECU, so everything looks seated well.

You sure all the sub connects are seated correctly? Not sure if any of the harnesses were removed to remove the ECU but if so make sure they are not backwards or mixed up.

Mike

[mj6234]

I think so. The ECU was repulled and reconnected to make sure. Is it easy to get one of the harnesses backward? It seemed like the wires were so short that it probably only could go back one way. I can get a picture if it is easy to tell by looking.

If it matters I don't have a piggyback, just Cobb for the tuning.

[theweebabySeamus]

Originally Posted by mj6234

I think so. The ECU was repulled and reconnected to make sure. Is it easy to get one of the harnesses backward? It seemed like the wires were so short that it probably only could go back one way. I can get a picture if it is easy to tell by looking.

If it matters I don't have a piggyback, just Cobb for the tuning.

All the arrows are facing the right way? I put my subconnectors in wrong for my jb4 install. They should go in the main plugs easily, if not theyre probably in the wrong slots.

[brewnami]

I've pulled my ECU out a few times and one time I didn't seat the sub connector perfectly and all it did was crank. I knew what it was right away, but you couldn't tell just by looking at it.