A 2011 BMW 740Li presented a crank no-start condition after sitting idle for an extended period. Using an Autel MaxiCheck MX808, initial diagnostics revealed various fault codes. This article outlines the diagnostic process using Autel and other tools, focusing on the remaining trouble codes and potential solutions.
After installing a new battery and registering it, a comprehensive diagnostic scan was performed using the Autel MaxiCheck MX808. The Autel also facilitated the recalibration of various vehicle functions, including windows, sunroof, seats, steering wheel, and steering angle. Following code clearing and subsequent cranking attempts, the vehicle failed to start.
A second scan, conducted with a Foxwell NT530, confirmed the persistence of two specific fault codes: E46C00 (signal (current personalization ignition key number, 0x23A) invalid, transmitter CAS/FEM/BDC) and a fault related to the AUC sensor.
Further diagnostics using ISTA+ confirmed these codes. Test plans within ISTA+ eliminated several potential causes, including showroom mode, a disabled key, issues with terminal 15 activation, and junction box malfunction.
The primary question remains: does the E46C00 code directly cause a crank no-start condition? It is understood that communication failures between the CAS module and other modules can prevent engine starting. A CAS-DME synchronization procedure is often recommended in such cases. However, locating the DME-CAS synchronization function within either the Foxwell NT530 or the ISTA+ software proved challenging. This difficulty raises the question of whether the specific model, a 740Li, impacts the availability or location of this function within the diagnostic software. Procedures documented for other BMW models, such as the E90 with the N54 engine and the F01 with the N63 engine, did not directly translate to this 740Li.
The diagnostic process continues, and any progress will be documented. The focus remains on understanding the E46C00 code and its potential link to the no-start condition, as well as identifying the correct procedure for DME-CAS synchronization on this specific BMW model using Autel or alternative diagnostic tools.
