P0599 P0599 code definition The P0599 code (http://bestride.com/engine-trouble-codes/p0599) (http://bestride.com/engine-trouble-codes/p0599) is stored when the PCM detects an abnormally high voltage reading from the thermostat heater unit. What the P0599 code means The thermostat heater unit requires inputs from a variety of...
