Engine code P0402

EvancLBZ · 11-09-2012, 01:16 PM

Pulled codes after check engine light has come on. Cleared code numerous times and still returns. Code says excessive EGR flow. Anyone have this issue with an easy solution. Some guys say EGR will be plugged up with carbon, others say mass air flow sensor. Just wanted to get someones opinion that has had this trouble or know the issue before spending some cash. Truck only has 79000kms.

**blunova** · 11-09-2012, 01:32 PM

I had that code when i went to after market af, put a blocker plate[egr] cleared the code did not come back on, now my egr is shut down with the efi live

EvancLBZ · 11-10-2012, 07:30 PM

Truck is completly stock, even the air filter. Probably sounds like the egr has to come off and be cleaned al least i guess. I bought a new ac delco air filter and im gonna put it in and clean the mass air flow sensor when i get a min of spare time. Hoping this cheap easy fix might do it.

Pearseam · 11-12-2012, 08:53 PM

EvancLBZ, Had the same problem, Pulled the EGR out and cleaned it 4 weeks ago. Fun times

It was about 90% blocked. This was my first time doing it at 92000 miles. Suggest while you have the EGR out just replace the EGR Solenoid (motor). Even after cleaning the EGR I was still getting the P0402 code. I even tested the motor for operation when I had the EGR out, it worked but I was still throwing the code. I just replaced the motor this weekend, hopefully that will be the end of it. Before pulling the EGR have at least 3 cans of cleaner I used B-12 throttle cleaner it works great. Good luck.

Dark Cloud · 11-15-2012, 10:37 AM

I had this issue with after market cold air intake and I asked the same question about a year ago. I got back from someone that some of them did throw the code with stock intake so they came out with a calibration update (dealer update code fix). I asked what the code was and he did not know but he ran a repair shop and it sounded like good info. I would try the other suggestions first but keep this in your back pocket.

EvancLBZ · 11-15-2012, 01:07 PM

Checked out code on identifix and out of 11 confirmed fixes, 7 of them were dirty mass air flow sensors, a couple were bad egr motors and one was software and the mass air flow sensor. Cleaned the mass air flow sensor this morning and threw in a new air filter. Gonna try this first. Thanks for all the info.

eluebke · 11-16-2012, 10:57 AM

I have been having this problem also since it started getting cold here. Once the temp dropped down into the 40's and 50's my engine light would come on just driving down the road at a steady speed. I can not notice any difference with the way the truck performed. I scanned it with the same P0402 code. My only problem is a few days later the light will go out by itself, only to come on again a few days later, sometimes it will be 2 weeks of driving before it comes back on. But it always comes on driving at a steady speed. I just had the light come back on yesterday for the 5th time in the last 7 weeks. For right now I will just keep driving the truck and see how long it takes to shut off again. Is this the same experience others are having? Or does the light come on and never go off until you clear the code yourself?
Thanks
Eric

EvancLBZ · 11-17-2012, 07:42 AM

The light comes on and stays until its cleared on my truck. Even after I clear it it might come back in ten minutes or a week. It also seemed to come on when the temp got low as well. Worked excellent all spring, summer and fall this year. After I cleaned the mass air flow sensor, the light hasn't come back yet. Hoping it cured.

Pearseam · 11-17-2012, 07:42 PM

eluebke, from my experience the CEL light comes and goes. Determined by when you start the truck and if the egr work properly or not. After replacing the egr motor last weekend I have not had a CEL come on at all this week. I'm saying its fixed. Usually I would have got the light by now, once a week off and then on. This weekend project was replacing the Lower Trans cooler line, not too bad of a job.

eluebke · 11-19-2012, 07:37 AM

My light has not gone back out since I posted. I think I may try a new air filter and clean the mass air flow sensor. This seems to be the easiest fix to try first. If this doesn't work, how hard was it to get at the egr itself to try to clean it and change the motor for it? I'm really getting sick of looking at the orange engine light on my dash.

11-09-2012, 01:16 PM	eBay Motors #1 (permalink)
EvancLBZ DuramaxForum n00b Join Date: Nov 2012 Location: Moosomin, Saskatchewan. Canada Posts: 14	Engine code P0402 Pulled codes after check engine light has come on. Cleared code numerous times and still returns. Code says excessive EGR flow. Anyone have this issue with an easy solution. Some guys say EGR will be plugged up with carbon, others say mass air flow sensor. Just wanted to get someones opinion that has had this trouble or know the issue before spending some cash. Truck only has 79000kms. __________________ 2007 Silverado Classic 2500 4x4 LBZ

11-09-2012, 01:32 PM	eBay Motors #2 (permalink)
blunova Duramax Lifetime Supporter Join Date: Jul 2012 Location: butler, pa Posts: 407	I had that code when i went to after market af, put a blocker plate[egr] cleared the code did not come back on, now my egr is shut down with the efi live __________________ 2007 Classic lbz Turbo back exhaust, Efi live auto cal from idaho Rob egr blocked, trans go jr, grizzly locker,leveled 285-75-16 wrangler duratracs radials on pro comp wheels,remote start, afe intake air dog 165, billstien 5100s,Afe intercooler pipe, pcv valve reroute, diamond eye down pipe , bushwacker pocket flares, BD exhaust manifold, g2 diff cover with girdle stage 5 trans coming soon. line x bed liner,extang trifold toneau,edge cts, allison deep pan with transynd fluid suncoast filter lock.

11-10-2012, 07:30 PM	eBay Motors #3 (permalink)
EvancLBZ DuramaxForum n00b Join Date: Nov 2012 Location: Moosomin, Saskatchewan. Canada Posts: 14	Truck is completly stock, even the air filter. Probably sounds like the egr has to come off and be cleaned al least i guess. I bought a new ac delco air filter and im gonna put it in and clean the mass air flow sensor when i get a min of spare time. Hoping this cheap easy fix might do it. __________________ 2007 Silverado Classic 2500 4x4 LBZ

11-12-2012, 08:53 PM	eBay Motors #4 (permalink)
Pearseam DuramaxForum n00b Join Date: Oct 2012 Location: Cochise County Arizona Posts: 24	EvancLBZ, Had the same problem, Pulled the EGR out and cleaned it 4 weeks ago. Fun times It was about 90% blocked. This was my first time doing it at 92000 miles. Suggest while you have the EGR out just replace the EGR Solenoid (motor). Even after cleaning the EGR I was still getting the P0402 code. I even tested the motor for operation when I had the EGR out, it worked but I was still throwing the code. I just replaced the motor this weekend, hopefully that will be the end of it. Before pulling the EGR have at least 3 cans of cleaner I used B-12 throttle cleaner it works great. Good luck. __________________ 07 Sierra 2500HD, LBZ, CC, SWB, 45 Gal Fuel Tank by Transfer Flow. No Mod's

11-15-2012, 10:37 AM	eBay Motors #5 (permalink)
Dark Cloud Junior Member Join Date: Jun 2011 Location: South Central, WI Posts: 78	I had this issue with after market cold air intake and I asked the same question about a year ago. I got back from someone that some of them did throw the code with stock intake so they came out with a calibration update (dealer update code fix). I asked what the code was and he did not know but he ran a repair shop and it sounded like good info. I would try the other suggestions first but keep this in your back pocket. __________________ 2006 Chevy Silverado LT 2500HD, LBZ, CCSB, 4x4. Add ons: Truxedo, TransGoJr, Ranch Hand Legend Front Bumper, Tow Mirrors, Xtreme Bed Liner, Recon Cab Lights, Bluetooth ODB II data thru Android Phone. Mods: Blue LED's in dash and all dash controls.

11-15-2012, 01:07 PM	eBay Motors #6 (permalink)
EvancLBZ DuramaxForum n00b Join Date: Nov 2012 Location: Moosomin, Saskatchewan. Canada Posts: 14	Checked out code on identifix and out of 11 confirmed fixes, 7 of them were dirty mass air flow sensors, a couple were bad egr motors and one was software and the mass air flow sensor. Cleaned the mass air flow sensor this morning and threw in a new air filter. Gonna try this first. Thanks for all the info. __________________ 2007 Silverado Classic 2500 4x4 LBZ

11-16-2012, 10:57 AM	eBay Motors #7 (permalink)
eluebke DuramaxForum n00b Join Date: Aug 2012 Location: Manitowoc, WI Posts: 18	I have been having this problem also since it started getting cold here. Once the temp dropped down into the 40's and 50's my engine light would come on just driving down the road at a steady speed. I can not notice any difference with the way the truck performed. I scanned it with the same P0402 code. My only problem is a few days later the light will go out by itself, only to come on again a few days later, sometimes it will be 2 weeks of driving before it comes back on. But it always comes on driving at a steady speed. I just had the light come back on yesterday for the 5th time in the last 7 weeks. For right now I will just keep driving the truck and see how long it takes to shut off again. Is this the same experience others are having? Or does the light come on and never go off until you clear the code yourself? Thanks Eric

11-17-2012, 07:42 AM	eBay Motors #8 (permalink)
EvancLBZ DuramaxForum n00b Join Date: Nov 2012 Location: Moosomin, Saskatchewan. Canada Posts: 14	The light comes on and stays until its cleared on my truck. Even after I clear it it might come back in ten minutes or a week. It also seemed to come on when the temp got low as well. Worked excellent all spring, summer and fall this year. After I cleaned the mass air flow sensor, the light hasn't come back yet. Hoping it cured. __________________ 2007 Silverado Classic 2500 4x4 LBZ

11-17-2012, 07:42 PM	eBay Motors #9 (permalink)
Pearseam DuramaxForum n00b Join Date: Oct 2012 Location: Cochise County Arizona Posts: 24	eluebke, from my experience the CEL light comes and goes. Determined by when you start the truck and if the egr work properly or not. After replacing the egr motor last weekend I have not had a CEL come on at all this week. I'm saying its fixed. Usually I would have got the light by now, once a week off and then on. This weekend project was replacing the Lower Trans cooler line, not too bad of a job. __________________ 07 Sierra 2500HD, LBZ, CC, SWB, 45 Gal Fuel Tank by Transfer Flow. No Mod's

11-19-2012, 07:37 AM	eBay Motors #10 (permalink)
eluebke DuramaxForum n00b Join Date: Aug 2012 Location: Manitowoc, WI Posts: 18	My light has not gone back out since I posted. I think I may try a new air filter and clean the mass air flow sensor. This seems to be the easiest fix to try first. If this doesn't work, how hard was it to get at the egr itself to try to clean it and change the motor for it? I'm really getting sick of looking at the orange engine light on my dash.

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