[por924]

My car is experiencing a very strange and unique issue that I cannot find any info on online! It will cold start without fail, but after it's fully warmed up, if I shut it off and try to start it again, it will start and run for exactly 3 seconds, then shut off as if I had pressed the start/stop button and completely turns off the car...engine off, no dash lights, and the steering wheel moves up out of the way! If I let it sit for about 30 minutes, it will start and run like normal again until it warms up, then it repeats the cycle. I have replaced the battery with a factory H9, coded and registered it. Voltage while running is 14.7 until it warms up then it drops to 14.1, and while driving under acceleration it drops to 13.5, then back up to 14.9 on deceleration. Please help!!!

[Pizzaboss]

Key fob??

[por924]

No, it starts up fine when cold, and when fully warmed up it does what I explained. Key fob never loses connection with the car

[Pizzaboss]

Sounds maybe your fuel pump might be starting to fail.

[jarsdad1]

Codes? Sounds like a fuel pump or sending unit about to go.

[M_Bimmer]

Originally Posted by por924

My car is experiencing a very strange and unique issue that I cannot find any info on online! It will cold start without fail, but after it's fully warmed up, if I shut it off and try to start it again, it will start and run for exactly 3 seconds, then shut off as if I had pressed the start/stop button and completely turns off the car...engine off, no dash lights, and the steering wheel moves up out of the way! If I let it sit for about 30 minutes, it will start and run like normal again until it warms up, then it repeats the cycle. I have replaced the battery with a factory H9, coded and registered it. Voltage while running is 14.7 until it warms up then it drops to 14.1, and while driving under acceleration it drops to 13.5, then back up to 14.9 on deceleration. Please help!!!

You need to run ISTA on your vehicle...find out what modules are not "green" and pull the BMW codes (not the OBD II emission codes). Someone on this forum with ISTA should be in the Las Vegas area that can help you.

If you cannot find ISTA, at least buy yourself a Foxwell NT530 BMW version scanner for $150 from Amazon.

Don't chase "ghosts".

[por924]

Thank you all for your input thus far

UPDATE...

I scanned it with my Autel and I get the following code in the CAS module AFTER the car is warmed up

930732

"Fault with engine starting during starter operation: relay sticking"

[CrippledLucifer]

Originally Posted by por924

Thank you all for your input thus far

UPDATE...

I scanned it with my Autel and I get the following code in the CAS module AFTER the car is warmed up

930732

"Fault with engine starting during starter operation: relay sticking"

That code appears to point to a faulty starter motor, but I am confused why it's exhibiting the type of behavior you mentioned.

I'd agree with the suggestion of getting a BMW specific scanner, if not ISTA. At least you'll know exactly what's going on that way and fix the issue rather than throw money at random parts hoping it'll rectify your problem.

[por924]

I'm hoping so, I'd hope it was the fuel pump instead but I planned on upgrading to a walbro anyway so at least that will be new here shortly.

Yes, the behavior of starting perfectly fine (after fully warmed up to operating temperature, about 30 minutes at idle), running for 3 seconds, then shutting off COMPLETELY, back to back to back consistently, is mind boggling 🤯

I believe I have ISTA or INPA on my laptop (it's been a while) so I'll run a diag and update here.

[por924]

starter operation: relay stcking

Fault memory
Fault description
Measurement via readback line: Readback level > threshold high
The fault is set as soon as the terminal control switches off terminal 15.
code
12A308
Condition for fault identification
Terminal 15 on
Condition for fault memory entry
Fault code entry is made after 3 seconds
Action in service
1. Check function of starter relay If necessary, renew relay or CAS
2. If relay is OK, check supply voltage of the starter motor and replace if necessary
3. If the voltage supply of the starter motor is OK, check functioning of the starter motor
separately and replace if necessary

Note on effect of fault
Starter motor turns in spite of missing activation (vehicle may Jump), ignition goes off i.e.
terminal 15 is automatically switched off. After engine start by button operation, the starter
motor continues turning briefly and engine stops


Driver information
Check Control message (21) Ignition fault!

[por924]

FIXED!!!

I replaced the starter with a NEW unit from FCP Euro and all is well so far! Thanks for everyone's help and input!