Check Engine light and codes help!

[Go Mifuni]

A few months back I had my gears, denso plugs and a chip (Diablo) installed by a reputable and highly recommended mech. When I picked it up, they said the chip was causing two codes to keep coming up. The codes come back as P0406 (EGR flow Sensor A [hand writing on the note not legible] high input) and P1451 (manufacturer control auxiliary emission controls). When I got it home, I disconnected the battery and pulled the chip. Started it up, drove it around and the light was off. I restarted it and the light came back on. In a nutshell: Whether or not the chip is installed, the light comes on on the second start.
I had no issues prior to having the work done and I can't take it back to the mech due to a.....tragedy.
Can anyone give me some ideas as to what to look at as far as these codes?

[LeoVampire]

A few months back I had my gears, denso plugs and a chip (Diablo) installed by a reputable and highly recommended mech. When I picked it up, they said the chip was causing two codes to keep coming up. The codes come back as P0406 (EGR flow Sensor A [hand writing on the note not legible] high input) and P1451 (manufacturer control auxiliary emission controls). When I got it home, I disconnected the battery and pulled the chip. Started it up, drove it around and the light was off. I restarted it and the light came back on. In a nutshell: Whether or not the chip is installed, the light comes on on the second start.
I had no issues prior to having the work done and I can't take it back to the mech due to a.....tragedy.
Can anyone give me some ideas as to what to look at as far as these codes?

That has been a common sensor to go bad over time.

Yes it sucks when something happens after work is done to a car but the 2 may not be related at all. It just may have been time for it to fail.

Pick up a service manual for the car at a parts store and do an oms test for the sensor the way the manual tells you to. That is the only way to find out for sure if it is bad or not.