The automaker planned to start work on the $5 billion plant this year.
The project recently secured initial approval for PPP-based construction.
The 84 km road was scheduled for completion in December 2022.
High Grand Falls Dam will hold 5.6 billion cubic metres of water.
The project stalled after China decided not to provide additional loans.
The proposed factory will be located in Mwingi Central, Kitui County.
The solar photovoltaic (PV) plant will be set on 80 hectares of land.
The facility will be five times the size of Dubai International Airport.
The Sh175 billion project is expected to get underway this year.
The cost of the project is now $6.4 billion, up from $5.7 billion.