System and Method for Improving Telematics Location Information and Reliability of E911 Calls

System, devices and methods are provided to automatically initiate an enhanced 911 (E911) call from a telematics control unit (TCU) (e.g., a TCU deployed with cellular modem or mobile phone in a vehicle) to an answering point (e.g. public safety answering point or access point (PSAP)). A wireless carrier (e.g., mobile service center (MSC)) employs a positioning determining entity (PDE) and algorithm to improve caller location determination using information provided by the TCU (e.g., GPS and dead reckoning information generated at the vehicle) and network location information when needed, and provides PDE estimated location of the caller to the PSAP (e.g., using a data channel and optionally a voice channel) to mitigate errors in TCU location data and reduce potentially conflicting location information provided to PSAPs from TCUs and wireless carriers or other phone service providers.