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The motorway F11 535XDWhen you lock your 2013 car and turn the key in the ignition, the lights will turn on.

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drivesafejane
Posts: 48
Joined: Mon Feb 02, 2026 9:02 pm

Greetings, I am experiencing a peculiar melding of two issues. After my car has been closed for approximately 10 minutes, the lights begin to turn on by themselves. Flashing lights, turning signals, and backup lights. As soon as I apply the brakes or switch to manual, the lights go out, only to return after ten minutes. As a result, I had to remove the battery to keep it from dying. Even without this, I was only able to get the vehicle started once since it came out. "Starter motor/ignition not working" is the idrive warning. To rule out any possible electronic shortcuts, I turned off the headlights. Several weeks pass with condensation on one headlight. Turning off the headlights has no effect. Pressing the start button does not supply 12 volts to the starter motor's solenoid. While the black cable remains at zero volts, the large red cable on the starter motor receives 12 volts. I removed the starter motor to supply 12V to the solenoid, and it activates. The starter motor appears to be in good working order, so my suspicion is that the car electronics are not being released for starting by the CAS module or others. Additionally, I disconnected the IBS, tried both keys, checked all fuses behind the glove box, verified all module connectors and pins, made sure there was no water ingress in the battery bay or around the glove box, and left the ground connected to the battery disconnected for a few hours or days. I also connected a running car to the jump start. Locking and unlocking the car, using the iDrive, and the keys all appear to be functional. I briefly detect a crackling sound when I press the start button, but I can't pinpoint its source. My OBD scanner is outdated. Even though the lights on my wireless dongle are on, it will no longer pair with the app on my phone. I verified that the value of 59 ohm for the CAN bus resistance on the OBD is accurate. The brake lights are functional, and the battery voltage is 12.5V when not in use, so the pedal switch must be functioning properly. The gearbox will not shift to N and remains in P.
Here is where my options run out; I'm thinking about contacting BMW for assistance.
This 2013 F11 535XDA has clocked in at 165,000 kilometres. Great ride when it's run properly.
NirviusTom
Posts: 68
Joined: Mon Feb 02, 2026 8:59 pm

You should ideally have ISTA scan the vehicle and pull up the recorded problems, test plans, and wiring diagrams.
Your description leads me to believe that you are at fault with either CAS or JBE
drivesafejane
Posts: 48
Joined: Mon Feb 02, 2026 9:02 pm

Updating: I have measured the amount of current drawn from the battery when the ignition is turned on for the car. The current steps up from 11.8 amps to more than 19 amps in a matter of seconds. My multimeter's wires were getting too hot, so I turned off the device. Even with the ignition turned off, there is a significant consumer drawing power from the battery. Another source could be using a lot of battery current, which is making the car refuse to start. "Which source?" is the question at hand. It seemed typical that the modules located in the battery compartment and behind the glove box did not experience any heating.
drivesafejane
Posts: 48
Joined: Mon Feb 02, 2026 9:02 pm

The error codes would gain a lot of knowledge, as you said. From what I understand, ISTA is quite pricey, and an advanced version is required in order to read CAS. From what little I know about the scanner industry, I gather that ISTA is pricey and that an upgraded version is required to read modules like CAS. I would prefer not to purchase a device that is inadequate in determining the precise location of the problem.
NirviusTom
Posts: 68
Joined: Mon Feb 02, 2026 8:59 pm

I purchased an Ethernet cable from Amazon for approximately £20 and installed my ISTA software, which I downloaded for free, onto a suitable laptop. Modules are read correctly.

I would check the main connections and earth points for high resistance, since you have a main positive cable that is getting warm.
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