Hello guys! I just recently received a P0128 error code on my 2007 Nissan Altima 2.5S and was wondering how many coolant thermostats are there? Nissan tells me, there is one but I have seen schematics showing there is two. I recently had my car serviced at a Nissan dealership and they have replaced one thermostat and re-filled coolant. However, a week and half later, the SES light came back and code P0128 was again detected.