Dear Dingaling,

This code is set when your egr temp sensor is warmed by exhaust gasses
when the vacuum solenoid is not energized by the engine computer.

EGR solenoid- Check at idle. Pull hose from EGR valve and check for
vacuum. If vaccum is present - turn off engine, disconnect solenoid
wire, re-test for vaccuum. If vacuum is present replace solenoid. If
vacuum disappears after disconnecting wires you have a faulty engine
computer.

EGR Valve - Sometimes stick or become lodged open. Common problems are
internally leaking EGR gaskets. On earlier enigines heat shields were
sandwiched between the EGR gaskets and were prone to rust through,
bypassing the EGR.

EGR sensor - sorry can't help you there; never replaced one. Mounted on
the bottom of the intake...

Solenoid test is simple but I suspect that you'll find burned through
gaskets and/or heat shield.

Regards,
Blake Dodson