Code P0401 keeps returning

WAYNED5

MEMBER
2000 PONTIAC GRAND PRIX
6 CYL
4WD
AUTOMATIC
88,500 MILES

My Service engine soon light came on.
Code: P0401, I bought a new EGR
I had the code reset.
On the way back home, the Service Engine Soon light returned. I had it checked.
Code: P0505. I bought a new IAC valve.
I had the code reset. A day and a half later the Service Engine Soon light came back on.
Code: P0401 (EGR AGAIN) My mechanic told me it didn't seem right. I followed his instructions to remove the EGR and run the care for 3-4 seconds. He thought maybe some of the gasket dropped down and this would clear it out.
He reset the code.
I drove another day. Guess what happened? That's right.
Service Engine Soon light came on.
Code: P0401

Any ideas on what to do next?
I am getting very frustrated. Thanks in advance.

Here is an update.
Code P0401 came on again today after driving about 35 miles
The tester I have lists Freeze Frame Data. Here are the results:
Fuel Sys 1 CL
Fuel Sys 2 CL-Fault
Calc Load(%) 3.53
ECT (F) 168
STFT B1 (%) -0.78
LTFT B1 (%) 7.03
MAP (inHG) 15.95
ENG RPM 1000
Veh Speed (mph) 24
MAF (lb/min) 0.85
TPS (%) 0.00

I tried to clean the terminals on the EGR and also verified that the PVC o ring was in good shape.

I reset the code and it came back on again today.

1 Reply

GCHICK1013

MEMBER
1 POST

There is a technical service bulletin on this and many shops are not aware of the situation. After much research on my own, I brought it to the attention of my guy. When an EGR valve is replaced on a series of GM cars from about 1999 on (my Grand Prix is 2001) the car's onboard computer needs to be "reflashed"--that is the technical term---because the computer is essentially viewing the new EGR as not its factory original.

Think of it as downloading the latest update or patch for your computer's operating system. Essentially, your car's computer will never need to be reflashed unless this partic. Component is replaced. Only GM dealers can do it, the cost running anywhere from $90-150.