Could be bad news. Have it checked for a cracked head gasket. I had a similar problem with mine -- had to replace the engine.
The 2003 Toyota Camry coolant temperature sensor can be found on top of the engine. The coolant temperature sensor will be near the center of the exhaust manifold.
The intake air temperature sensor is located on top of the intake. In a 1990 Toyota Camry the air temp sensor assures the ECU the engine is running at optimal temperature.
The 2006 Toyota Camry has an inline 4 engine.
The 2010 Toyota Camry has an inline 4 engine.
The 2007 Toyota Camry has an inline 4 engine.
The 2002 Toyota Camry has an inline 4 engine.
The 2004 Toyota Camry has an inline 4 engine.
The 2014 Toyota Camry has an inline 4 engine.
The 2012 Toyota Camry has an inline 4 engine.
The 2013 Toyota Camry has an inline 4 engine.
The 2008 Toyota Camry has an inline 4 engine.
The 2001 Toyota Camry has an inline 4 engine.