The engine would not crank over but leave it a few minutes and it starts?

Tiny
MICHV
  • MEMBER
  • 2015 BMW X5
  • 4WD
  • AUTOMATIC
  • 120,000 MILES
Hi, over the last few months our car model has had issues starting. It is not the battery, otherwise it would start fine. The car would not start but leave it a few minutes and it starts. It seemed worse in hotter weather. It is fine for a while then it starts again. We just never know when or where this problem will occur. I can't take it to anyone to just check, because everyone wants to charge a lot of money just to look at the car. I want to find the problem myself. Can you perhaps advise on what you think it could be?
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Monday, October 3rd, 2022 AT 9:46 AM

3 Replies

Tiny
KEN L
  • ADMIN
So, when you say the engine will not start do you mean the engine will not crank over or the engine cranks over but will not run? Please upload a short video of the problem so we can see it and, in the meantime, please go over these guides to glean additional information to help us fix the problem for you.

https://www.2carpros.com/articles/car-cranks-but-wont-start

Let us know what happens and please upload pictures or videos of the problem.
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Monday, October 3rd, 2022 AT 4:04 PM
Tiny
MICHV
  • MEMBER
The starting problem is intermittent. So, on pressing the brake and ignition button normally the car cranks and starts immediately. Intermittently over the last few months ( more so when the car is hot or has been running for a while) when pressing the start/ignition button, either the car cranks' once and then stops, doing nothing more ( not even clicking, like there is no current going to the starter at all) or it continues to crank but not start ( Like there's current going to the starter but no fuel pumping). On one or 2 occasions the main screen will go blank and read "no signal" as well. The battery seems strong so it does not seem like a current/voltage issue and its not spark plugs etc, as once the car is going it runs perfectly. My suspicions are maybe the immobilizer or maybe some sort of relay that works fine at some times but not at others (when car is hot). But seeing the screen go off and have to "reboot" I'm thinking definitely something electrical. Buy switching the car off and waiting a few minutes it starts no problem again. I think I will clean the battery terminals next but am hoping there are previous diagnostics from other cars regarding faulty relays/fuses or sensors that I can just replace. (I include photos that I have, will need to do a video when it happens again). Thank you!
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Monday, October 3rd, 2022 AT 5:11 PM
Tiny
KEN L
  • ADMIN
Yep, is the security light flashing when you try to start it? If not, the battery is weak and needs to be replaced but to be sure this guide can help you find out with no equipment needed. Also, I have included how to change the battery out in the images below.

https://www.2carpros.com/articles/car-battery-load-test

Battery replacement information
REP-ALG-RAF0161-6120BAT-HINWEISE_F - V.20

A vehicle battery is constructed for the installation location and the individual power requirements of the particular vehicle. These individual power requirements depend on the motorization and different types of equipment. The individually assigned vehicle battery is the ideal compromise between the power requirements of the vehicle electrical system and the weight and service life of the vehicle battery.

Vehicles with the automatic engine start-stop function or particular engine types and optional equipment are equipped with a special vehicle battery (AGM battery), since only this battery type can provide elevated power requirements over the extended service life. Installing a different vehicle battery can cause problems with vehicle electronics, can reduce functions or can cause leakage of battery acid.

In the event of an accident where the airbags are deployed in vehicles with a vehicle battery in the trunk, the electrical connection between the vehicle battery and the trigger is automatically disconnected through pyrotechnics. This prevents possible short-circuiting.

Proper operation of all of these safety and convenience functions requires a battery that conforms with specifications and that is properly registered in vehicles with energy management systems (IBS, power module).

Vehicles with energy management systems (IBS, power module): Register battery replacement

The vehicle electrical system is informed about the vehicle battery characteristic data, such as type, size, age and current power capacity. Therefore, there will always be only one work scope provided that is permitted by the current status of information.

If the performance readiness undershoots a defined minimum, a Check Control message will be generated to advise the driver that the battery must be replaced.

When installing a new vehicle battery, the battery must be registered and thus must also be registered with the vehicle electrical system.

Note:
Only this registration/login will ensure that the corresponding Check Control message will extinguish again.

Diagnostic system:

Register battery change

Service functions

Body

Voltage supply

Register battery change

When retrofitting, a more powerful battery may be used. Standard batteries may always be replaced by AGM batteries with the same specifications.

When installing a battery of a different size or a different battery type, this change in vehicle data must be programmed into the vehicle data in accordance with specifications.

Programming system:

Battery retrofitting

Check out the images (below). Let us know what happens and please upload pictures or videos of the problem.
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Tuesday, October 4th, 2022 AT 2:15 PM

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