DTC P0406

[R. Spence]

I have just replaced the Boost sensor and waste gate solenoid and the truck ran great for 4 days. Then today it set the P0406 code during normal in city driving.(with the AC running)My code reader says this is EGR flow sensor/high input.
Can someone exlpain this and is this refering to the manifold air flow sensor?
I am a novice to the diesel world and it seems quiet different from the gas world in many ways.
The EGR gets its signal from the ECM I think. I 'm a little confused....
The truck is a '96 6.5TD "S" series in a 1500 silverado.(toy truck)

[patrick m.]

egr valve is probably stuck. usually means "pintle position error".

egr valve is either stuck open, (somewhat)
or stuck shut.

[JohnC]

This code means the sensor voltage was higher than the normal range. Often it means one of the wires is open circuit, or a loose connection at the sensor itself. It could be afaulty sensor, too. An actual reading from the sensor should not set this code.

[R. Spence]

I have checked the EGR valve with a hand pump.
It opens and closes with in range and will hold Vacuum (for 30 minutes when left alone).
Could it be seizing when the engine is at running temp? That was when the SES usually came on..
It was setting EGR codes for a while then it quit.
I have checked for broken wires and so far have found none. But I will keep checking...

Thanks

[R. Spence]

Problem solved!! smile.gif It was a bad ground wire (circut "A" / Baro sensor)I put a jumper from "A" to the fire wall and it works great.
Ah this wonderful world of electronics!!
Thanks guys!!!

Bob