have 4inch magnaflow turbo back, k and n, and triple dog. has anyone else had 402 code come on. every one i talk too has had 401 and 403 but not 402. i have found that the code bypass will not work on lbz like it will on lly. PLEASE HELP!!!!!!!!!!!!

have 4inch magnaflow turbo back, k and n, and triple dog. has anyone else had 402 code come on. every one i talk too has had 401 and 403 but not 402. i have found that the code bypass will not work on lbz like it will on lly. PLEASE HELP!!!!!!!!!!!!

PO402 Is Exhaust Gas Recirculation Flow Excessive. Thats what that code stands for.

that wasnt the question but thanks for tring

My guess would be that if you deleted your converter you dont have enough back pressure for the EGR to operate correctly. My guess would be you need a blocker plate and finger stick.

Document ID# 1857814
2007 GMC Truck Sierra - 4WD
DTC P0401 or P0402

<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1857814&psdid=1647&evc=sm#ss1-1857814">Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle (http://service.gm.com/servlets/CellHandler?CellId=72794&RefDoc=1857814&evc=sm) prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis (http://service.gm.com/servlets/CellHandler?CellId=161235&RefDoc=1857814&evc=sm) for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions (http://service.gm.com/servlets/CellHandler?CellId=161236&RefDoc=1857814&evc=sm) provides an overview of each diagnostic category.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1857814&psdid=1647&evc=sm#ss2-1857814">DTC Descriptors

DTC P0401: Exhaust Gas Recirculation (EGR) Flow Insufficient

DTC P0402: Exhaust Gas Recirculation (EGR) Flow Excessive

<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1857814&psdid=1647&evc=sm#ss3-1857814">
Circuit/System Description

The engine control module (ECM) tests the exhaust gas recirculation (EGR) flow when the EGR is in operation. EGR desired flow is compared to EGR actual flow. If EGR flow is lower or higher than expected DTC P0401 or P0402 will set.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1857814&psdid=1647&evc=sm#ss4-1857814">Conditions for Running the DTC

• DTCs P0101, P0102, P0103, P0403, P0405, P0406, P046C are not set.
• The engine is running
• The EGR valve is actively being controlled.
• DTCs P0401 and P0402 run continuously when the above conditions are met.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1857814&psdid=1647&evc=sm#ss5-1857814">Conditions for Setting the DTC

P0401

The ECM calculated air flow deviation based on the MAF sensor input during EGR operation indicates insufficient EGR flow for 15 seconds.
P0402

The ECM calculated air flow deviation based on the MAF sensor input during EGR operation indicates excessive EGR flow for 15 seconds.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1857814&psdid=1647&evc=sm#ss6-1857814">Action Taken When the DTC Sets

DTCs P0401 is a Type B DTC.
DTC P0402 is a Type A DTC.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1857814&psdid=1647&evc=sm#ss7-1857814">Conditions for Clearing the DTC

DTCs P0401 is a Type B DTC.
DTC P0402 is a Type A DTC.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1857814&psdid=1647&evc=sm#ss8-1857814">Diagnostic Aids

Inspect for the following conditions that may cause this DTC to set:
• Contamination on the MAF sensor element
• Restriction before or after the MAF
• Skewed MAF sensor
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1857814&psdid=1647&evc=sm#ss9-1857814">Reference Information

Fingerstick will not stop the 402.

I think the K&N has hosed the MAF sensor. Take it out, clean it and see if the code goes away. (the sensor, not the filter...)

I get the 402 code too once in awhile. I do not have a aftermarket air filter. I do have a finger stick, blocker plate & the banks six gun has an egr defeat program. Do you think I have a bad sensor or egr?

minisub you are the man!!!!!!!!!!!!! a small piece of plastic from my k and n got stuck in my MAF sensor. if i could reach you i would kiss you, well maybe a hand shake. anyway thank you.

I just finished another post about K&N and MAF issues, I missed the fact you were running a K&N......sorry if I sent you in the wrong direction....