The saying is true; you never realize how important something is until it is gone. If your BMW won't start, you may feel hopeless and desperate as you are left stranded with no transport. Suddenly you realize how important your BMW really is now that you cannot drive it.
If you have a push-button start mode in your BMW, then there is no turn of the key to even try to get the slightest response from your car. While the push-button start is the next generation of keyless entry for your BMW, you may not completely understand how it works and what to do when your BMW won't start. Continue reading as we explore the topic in further detail.
What is a Push Button Ignition?
Push-button start cars, including those manufactured by BMW, use a keyless ignition system. The fob needs to be inside the car when you push the start button to start the engine. The fob connects to the car's computer system and allows the driver to start the engine without a key physically turning the ignition. Basically, the fob sends out low-frequency signals to the car.
The ID signal emitted by the fob is unique to that vehicle it connects with. The car's receiver will pick up the signal and respond by sending power to the engine.
BMW Push Button Start
Up until the mid-'90s, keyless entry was a luxury granted to only a handful of premium cars. Many BMW's of the '90s still needed a physical key to be inserted into the door to unlock it and then into the ignition to get the engine started.
It wasn't until the early 2000s that BMW started producing cars with a push-button ignition, and the trend is growing, even amongst the more affordable models.
According to statistics released by the National Highway Traffic Administration (NHTSA), only 5,000 cars, of all makes and models, had been produced in 2002 with a push-button start. By 2013, Ward's Auto reported the numbers to be close to 4,4 million, and they are still on the rise as more cars enter the market with a push-button ignition.
However, BMW has evolved their key once again as technology reaches new heights in the automotive industry. Recently, they have completely revamped their keyfob. The new i8 and 7 series models now have a fully interactive remote control device that goes beyond a physical instrument that signals the engine to start.
The push-button start system is convenient, and it has contributed to fewer auto thefts, however, there are some downsides to owning a BMW with a push-button start.
One disadvantage is that your keyfob may be one of the problems if your BMW won't start. Let's explore some of the problems behind why your BMW won't start, especially when you have a push-button start engine.
Why Your BMW Won't Start
If your engine does not crank when you push the start button in your BMW, then you may be experiencing one of these problems:
- Weak key fob battery
- Damaged key
- Defective push-button start system
- Bad fuel pump or relay
- Worn spark plugs
- Damaged fuses or relays
- Engine temperature sensor or PCM coolant sensor
- Defective ignition coil
There could be a conventional electrical problem preventing your car from starting, such as:
- A bad starter motor. A failed or damaged starter motor will not be able to crank your engine. If you suspect the starter is the reason behind the car not starting, then attempt to jump it directly. If, after that, the engine still won't start, then you may need to replace the starter motor or get a new relay, module, or solenoid. The starter motor is connected to the car's battery. A common cause of a BMW starter motor failing is a dead battery. In this case, you could replace the battery with a new one.
- A dead or discharged car battery. If your key is working, but your engine will not crank, then you may have a discharged or dead car battery. A dead battery is the most common reason why your BMW won't start. If the battery does not have enough charge, it will not crank the engine or use any electrical components. You can jump-start your car to see if the battery is the problem. If the car starts, then the battery is most likely dying, or you have a problem alternator.
- A fault in the starter circuit. There could be a small fault somewhere in the starter circuit or with the connections to the car's battery. Check the solenoid first. It will click as the contacts close if it is working. If it is not working, then there may be a fault with the ignition switch and its terminals, the wiring, or the solenoid itself.
While some of these problems are general across all BMW models, some are also specific to those that have a push-button start engine.
Let's explore why your BMW won't start with a push-button start engine in further detail.
Dead / Weak Key Fob Battery
Your keyless engine will not start unless it detects the key is inside your BMW. If the key fob is inside your vehicle and the engine still won't start, then the battery may be dead in the key itself. A key fob with a drained battery is rendered useless since the car's system will not recognize the fob inside the car. Not only do you have an inactive key, but a car that won't start either.
There is a way around this, though. You may not be able to unlock your vehicle remotely, but you can still access your car and start it manually.
To unlock your door:
- Press and hold down the key release button found at the base of your fob.
- Slide out the internal key blade and use it as a traditional key to unlock the doors.
- If you cannot find the keyhole on your car's door, then look for a small hole on the bottom of the handle.
- Insert the key blade into that hole and pry off the trim panel.
- This exercise should reveal the keyhole to gain access into the car.
To start the car manually, you can:
- Insert the key fob into the ignition slot if you have one.
- Hold the key fob against the markings found on the side of the steering column.
- Place the fob on the start engine button and press down.
While all of the above are helpful tips to gain entry into your BMW and to manually start it, rather replace the key fob's battery as soon as possible. You will need to switch out the battery for either a CR2450 or CR2032, depending on your BMW fob.
Damaged BMW Key Fob
If the battery is not at fault in your key and your BMW won't start, then your key fob may be damaged.
The key may be repaired; however, it may be easier and possibly less expensive to replace the key with a new one.
If you opt to replace the key entirely, then the starting price for a BMW key fob is $300. More advanced and new BMW models carry a higher price tag for a replacement fob.
Defective Push Button Start System
Technology is great, and many drivers favor the push-button start system. However, just like any other electronic gadgetry, things can go wrong. More often than not, they do go wrong. If your BMW won't start, and the battery has not died in your key fob, then the push-button start system itself may be defective.
Below are some of the possible causes of a defective push-button start system, and possibly why your BMW won't start:
- Defective push button or a fault inside the push button wiring harness.
- Defective clutch or brake pedal position switch. This could also be due to a fault in the switch wiring harness.
- Defective Park / Neutral safety switch.
- Defective steering interlock release module.
The Engine Cranks, But Your BMW Won't Start.
If the engine does crank when the push start button is pressed, then it is likely that the fault does not lie in the push-button start system. If this is the case, and the anti-theft light is not flashing, then check for:
- Fuel problems: Such as a bad fuel pump, plugged fuel filter, no gas, or a bad fuel pump relay.
- Ignition problems; There could be an issue with the ignition control module, or you may have a bad crank sensor.
- Mechanical problems: You could have broken teeth on the flywheel or a broken timing belt. Some mechanical problems are caused by a lack of engine oil or very old engine oil.
If the engine cranks slowly, but it still won't start, then a weak or discharged car battery could also be a cause. If it cranks slower and slower until you just hear a clicking noise, then your starter motor does not have enough power to turn over your BMW engine.
Diagnosing the cause of the problem behind your BMW not starting will help you determine the appropriate solution. When in doubt, rather consult a professional to assist you.