twinntrbo

Hi again, I replaced the voltage regulator and chacked all grounds but did not helped, I erased all learned data from ista and let the car start to relearn everything, for aprox100 km it was amazing, i did not get any voltage drops even on full throttle, but afer a while it started again. they also checked the belt but it looks tight

Hi Dave, I have some critical observations regarding the voltage issues we discussed. I’ve been monitoring the live data via the BM6 app and found a direct correlation between the voltage drops and the car's performance: • Momentary Power Loss: At the exact moment the car feels like it’s "hitting a wall" and loses power, the voltage at the battery drops instantly to 12.5V while driving. Normally, it stays around 14.2V - 14.5V. • Transmission Issues: While cruising, the voltage is very unstable, fluctuating between 14.0V, 13.9V, and sometimes dipping to 13.6V. Whenever these fluctuations occur, the transmission shifts become very jerky and harsh. • The "Reset" Effect: I performed a battery registration via ISTA+ and went for a test drive. For the first 50 km, the car was incredibly stable; the voltage stayed solid at 14.4V - 14.5V, and the gear shifts were flawless. However, after that period, the erratic behavior and voltage drops returned. • Cranking Voltage: During the first cold start, the voltage drops significantly to 9.6V - 9.8V. Interestingly, if I stop the engine and immediately restart it (without removing the key/terminal 15), the cranking voltage stays much higher and the car starts much "healthier." It seems like the DME/IBS is losing its calibration or there is a major resistance issue (possibly the ground strap) that triggers these momentary charging cut-offs, especially under load. What do you make of this "temporary recovery" after ISTA registration followed by a relapse

Thank you Dave, Then what do you think about cf25 fault? I tought it was a transmission issue,

Merry Christmas and Happy Holidays everyone! I am trying to diagnose a scary electrical issue with my 2007 E92 330i. The Main Symptoms: 1. Sudden Power Cut: While driving, the car suddenly cuts throttle/power. At that exact moment, the Service Light flashes briefly, and the transmission throws code CF25 (EGS: Message from engine control Alive signal fault). • Note: I used to get CF1C, but now it is consistently CF25. 2. Hesitant Crank: When starting the car, the starter turns for a split second, pauses/stops completely, and then continues to turn sluggishly until the engine fires. 3. Sensor Dropouts: My AFR readings (O2 sensor) appear and disappear intermittently. I really need help, battery voltage is 12.4 when is off, when is on 13.9-14.1 v And also I was not at home for 19 days and battery was still alive after 19 days so I think its not the battery. But another problem is when i turn it off and lock it , the park light on shifter doesnt turn off, even after 19 days it was on.