Toyota Repair: Camry V6 1997 OBD Code 402 EGR Open, egr valve position, egr valve position sensor

Question
Before I begin looking and fixing the obvious loose vacuum lines, etc, what are the odds of just replacing the EGR valve and not testing the rest:  EGR gas temp sensor, EGR valve postion sensor, Vacuum control valve, or vacuum switching valve.  Anything quick and dirty?   Isn't the EGR valve most likely to fail at only 52,000 miles?

Thanks,
Lenny in Austin, TX

Answer
EGR valve failures are rare on this model so I don't think it's the problem at this time, in this case the most likely cause is the vacuum switching valve(VSV)It could be holding the egr valve open too long, if the egr valve was staying open at idle the idle would be rough and erratic.
If the problem was the egr valve position sensor there would be a different DTC.
The next most likely case would be a bad exhaust gas temp sensor, take a look at the connector and make sure it's connected.