Regarding keyless ignition switches, I have a stupid query. I’ve seen that as a first step, you “change your ignition switch to R or terminal 15” in a number of manuals and how-to instruction pamphlets. Could someone kindly explain how a 2005 745i keyless ignition works? See, I warned you that was foolish, but I’m not really sure of the solution. Thanks
what instructions should be included in flyers? You intend to start the vehicle. Put the remote in your lap, depress the brake, and push the start/stop button while sitting in the car.
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Huffman, Doug
Depending on how the start/stop button is used, the CAS is responsible for controlling terminal 15. (with the remote key or ID transmitter inserted in the insertion slot). A semiconductor switch in the CAS is used to switch the terminal 15. A semiconductor switch’s output triggers a relay in the rear power distribution box.
the control units that terminal 15 (the rear power distribution box) provides:
The most crucial information for comprehending the capabilities and flaws of the BMW electrical system may be found on the page newtis.info linked above. To understand, it requires frequent and attentive reading.
What does terminal R mean?
Actually, Terminal R is “running,” while Terminal 15 is an accessory (also known as Position 1 on the Ignition Switch) (aka position 2 on ignition switch). There is a distinction because devices like headlights are powered in position 2 but not in position 1, indicating a difference.
An electromagnetic switch serves as the starter motor solenoid. When the starter button or ignition switch is in the starter crank position, power is provided to the coil windings at terminal 50. This makes it possible for electricity to move from the car battery to the starter motor.
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The general procedure for starting the engine is as follows:
* The EWS data is read from the remote control’s data memory by a ring coil in the CAS control unit. The remote control is secured in position in the ignition lock if it is a genuine, functional key for the car.
The CAS then transmits the command (terminal R on) through the data buses following this locking. Numerous control systems are turned on as a result.
* The four outputs at CAS terminal 15 are activated. Through terminal 15-3, the relief relay for the ignition coils is turned on.
All of the control units connected to the PT-CAN data bus are enabled upon activation of the outputs terminal 15 WUP (wake-up).
The CAS determines whether the brake pedal is depressed and the gear selector lever is in the P or N position when the start-stop button is pressed. The engine is started if this circumstance is true:
* The CAS switches a positive (battery voltage) at the DME control unit across line terminal 50E, indicating that the engine is to be started.
* The CAS switches a positive (battery voltage) at the comfort start relay across terminal 50L. The starter motor has been activated.
* A random EWS code is transmitted to the DME control unit via the data line D-EWS.
* The engine control unit checks the calculated code to the random code sent over the air. The fuel injection and ignition are turned on if they line up.
Until the CAS control unit receives the signal (Engine running) from the engine control unit through the data channel, the starting motor continues to turn. The CAS terminals 50 are then turned off.
Terminals 50 are deactivated after a maximum of 20 seconds and the engine start is interrupted if the engine doesn’t start.
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Recently, it periodically starts up with the error message “Drivetrain problem, drive moderately,” but otherwise functions as it should. Only upon startup, the error generally disappears on its own after a few kilometers. The issue has never happened when the car is moving, even though I’ve disabled stop/start as a precaution. The ensuing codes are displayed:
- 1C0202 – Short circuit to earth on the engine oil pressure control valve
- 120408 – Shutdown as a response to boost pressure control
- Lambda probe heating following a catalytic converter short circuit to ground (12B102)
- Air mass meter, electrical fault signal (102A01)
- 1D2402 – Short circuit to ground in the map thermostat control
I would assume this is a starting relay issue in any other automobile. My best opinion is that the starter may be utilizing too much power, causing the DME to brown out and resulting in all the aforementioned random shorts at Terminal 15N, which is post-start ignition on.
Since no other system (FEM, etc., etc.) displays any errors upon startup, I may also be suspecting a problem with the DME cabling.
However, as far as I can tell, the F30 lacks a detachable starter relay. Either the front power distribution box, the rear power distribution box, or the power distribution module on the driver’s side would need to be replaced.
I’ve been avoiding the issue by hitting the start button while keeping my foot off the brake, allowing the computers to start up, and then turning the key to start the engine. According to the underlying idea, whatever the issue, it is made worse by the simultaneous power demands of each system during startup, and thus staggered startup process will even out the power demand.
Although I’ve never experienced the error when performing this action, absence of evidence does not prove absence.
Because I thought it might be DME electronics, I also removed the engine cover to check the connections to the ECU for looseness. They seemed okay.
However, I’d prefer to actually resolve this issue. In the same order as above, I anticipate the power distribution modules, power distribution boxes, and possibly the ECU wire harness.
I detest trying to fix occasional problems with parts. It frequently makes things worse.
Did you ever find a solution to this? obtaining the same set of codes repeatedly and being unable to start the automobile at all; it cranks but does not move. IVM and IVM cable have already been replaced after a break was discovered in that cable.
How do I turn on the remote start for my BMW?
You can activate Remote Engine Start by pointing your BMW key fob at your car and pressing the lock button (the BMW Roundel) three times in a row.
On a BMW, what is Terminal 50?
The starter motor activation voltage comes from CAS at terminal 50. The most common initial cause of a burned CAS module is a subpar engine ground cable. In order to determine whether there is activation voltage at the starter motor and, if not, to examine the CAS module.
If you have the time, I’d want to hear the theory behind this. I can see that the internal cas relay likely uses a diode to connect terminal 30 to 50 to the white relay in your photo. I don’t have a schematic for a circuit. Why would this occur if the engine ground was bad? It is impossible for the burned-out diode in your photo to be the one connected to the terminal 50 o/p. The tiny track is burned, and that is presumably the relay coil diode since it is too small. Why did this occur?
How can I exit the theft mode on my BMW?
Put the key into the door lock as the first step. Use the side door on the driver’s side and put the physical key into the lock even if you have a keyless car and don’t frequently use it.
Tip: The majority of key fobs—if not all of them—contain a real key. Look for a button that releases the actual key from the fob so you can slide it out.
Step 2: Rotate the car key to open the door without opening it. Keep the key in this position for 30 seconds. By doing so, you will let your car’s security system know that you have the right key and can disable the alarm.
Some vehicles can be accessed by merely twisting the key in the door’s cylinder back and forth. To disable the anti-theft system, it is advisable to attempt both holding the key in the door and twisting the key in both directions.
Step 3: Attempt to start the car. Remove your car’s key from the door and attempt starting the engine. Make sure the door cylinder is still in the unlocked position as you do this, though.
How can I reset the computer in my BMW?
My automobile won’t turn over. After some web study, it appears that the ECU is most likely the problem. How can the factory settings be restored on a BMW computer?
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Amazing investigative abilities! Unplugging the negative battery cable for 10 to 15 minutes will reset a BMW ECU. For most BMW models, this ought to be sufficient to reset the ECU.
You can also try jumpstarting your car to reset it if this doesn’t work. If a low battery is the problem, this will also be helpful!
However, if you still have trouble starting your car after jumping the battery, you should speak with a mechanic to find out more about what’s going on.
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How can my BMW key fob be reset?
- Insert the key into the ignition.
- Turn it so that it is on.
- Then switch it off.
- Remove the key next.
- Finally, while maintaining pressure on your key fob’s unlock button, push the BMW logo button three times. After that, release the unlock button.
Why won’t my BMW start despite clicking?
When trying to start your car, a loud clicking sound may indicate an issue with the electrical system. It’s possible that your battery is dead or that the alternator, which charges the battery, is malfunctioning.
The starter, a small motor powered by the battery that starts the engine, is unable to maintain power if the clicking noise is electrical in origin. Instead, it makes a clicking sound and switches on and off quickly.
Remember that in situations like this, a misfiring starter is really a symptom and not the root of the problem. Your automobile’s electrical system is probably to blame, which is why a jumpstart could briefly move your car.
Once it’s operating, have an experienced technician inspect the entire electrical system. Your alternator or battery might need to be replaced. Alternately, the issue might be resolved by simply cleaning the battery terminals of corrosion to improve the battery’s connection.
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Does my BMW require reprogramming after a battery change?
Let’s first focus on what BMW battery registration genuinely is before delving into the procedure. Battery registration, to put it simply, is the process of notifying your car that a brand-new battery has been installed. Importantly, it must be done every time you replace the battery in your BMW, model year 2002 or later.
The car adapts the amount of energy required to recharge to operate at peak levels as your battery ages and gradually loses its ability to charge. The battery needs more charging the older it is. By registering your battery, you can inform your engine control module (also referred to as DME — Digital Motor Electronics) that a new one has been installed. As a result, the vehicle will reset the old battery statistics and won’t attempt to overcharge the new battery under the assumption that the old one is still in place.
In addition to registering, you must also code your BMW computer. No matter how different or similar your new battery is from your previous one in terms of specifications, it will still be necessary each time you change it.