Toyota Repair: PO 402, exhaust gas temperature, egr system

Question
i have a 1995 Toyota camry i have a check engine light PO 402 i will like to know if it is the egr or somethink more

Answer
This code means that there is too much egr gas flow, this could be due to an egr valve that is staying open but in that case there would be a rough idle, it could also be a malfunctioning egr vacuum switching valve or a malfunctioning gas temp sensor, these require special equipment to test, the egr vbalve is tested with a vacuum pump for operation, the gas temp reading requires the use of a scantool that can read exhaust gas temperature, the problem is only related to the egr system.