P0401 1999 Toyota Camry -

Question

I have changed the vsv, egr valve and vacuum module and still have the P0401 all the vacuum lines are clear and I have vaccum to the egr valve what else would cause a P0401 I also replaced the ECU and no change

Answer 1

P0401 Exhaust gas recirculation flow insufficient detected

Thermostat that is missing or not operating correctly will set this code, the reason if the engine does not reach the specified operating temperature you will not get EGR when you are suppose to

 The VSV valve operates at a specified temperature