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BOBBYSS
BOBBYSS, Master Technician
Category: Chevy
Satisfied Customers: 17142
Experience:  ASE MASTER CERTIFIED, AA DEGREE AUTO/DIESEL TECH
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Chevy 3500: 2009 chevy duramax reduce power mode

Customer Question

2009 chevy duramax reduce power mode
Submitted: 1 year ago.
Category: Chevy
Expert:  BOBBYSS replied 1 year ago.
Hello, my name is***** for the question. If I am not online when you return please give me some time to get back to you. Does this happen every time you drive it? Is the check engine light coming on also?
Customer: replied 1 year ago.
the check engine light did come on, had the code tested said bad mass air flow sensor we replaced sensor and still same problem. It will start and drive .if you shut it off when you restart it goes into reduce engine power mood.then let set for a time and it will start up again
Customer: replied 1 year ago.
the truck has 40000 miles is all. First time it happened we changed air cleaner and it started right up. thought we had it fixed we shut it off and restarted it and it went right back into reduced power mode . Replaced fuel filter also
Expert:  BOBBYSS replied 1 year ago.
Thank you. I would start by checking the connections at the battery. If you have a poor connection or if you have a failing battery this will occur. I would load test the batteries to verify their health. If the batteries are fine then check the wiring connection at the ECM under the hood.
Customer: replied 1 year ago.
the batteries are good where is the ecm located
Expert:  BOBBYSS replied 1 year ago.
It is located under the hood on the drivers side next to the radiator. I would check the connections for dirt and corrosion. There are also issues with the wiring under the driver side kick panel under the dash and under the plastic body molding from the kick panel to the pillar. One other thing you want to make sure of is that the air filter housing is not restricted in any way.
Customer: replied 1 year ago.
is there a way to reset the check engine light. We are checking wires and air restrictions on the air cleaner. Every time it goes into reduced power mode we take air cleaner out and put back in. After a few minutes and it runs good till we shut it off then when we restart it goes right back in reduced power mode.
Expert:  BOBBYSS replied 1 year ago.
The only true way to reset the computer is with a scan tool. You can unhook the battery to try. Is the air cleaner pick up tube clear?
Customer: replied 1 year ago.
Thanks for the help Bobby, Yes we checked that this morning. I checked all the wire connectors on the computer as well as under dash . I took air compressor and blew out all plugins as well as the throttle position sensor. I started it up drove it 15 miles stopped at gas station. When i restarted it in 5 minutes and it went right to reduced power mode. Let it set for 15 to 20 minutes and it starts right and will run ok till i shut it off again, then it will not run except in reduced engine mode. It acts like it has to cool down then it will start , Temp gauge looks same as always has and coolant is full.
Customer: replied 1 year ago.
i have been studying other questions asked on here. This sound similar to mine but it is a 06. The Chevy mechanic says "There is a common issue with these engines. It is the fuel pressure relief valve. This valve is a small plug in the end of the drivers side fuel rail. When they get hot, the start to open a bit too soon and set this code. There is a cheap solution to this. A shim that will hold the pressure back." Here is a website that sells these shims. http://dmaxstore.com/index.php?main_page=product_info&products_id=93Read more: http://www.justanswer.com/chevy/4bjvh-chevrolet-06-silverado-intermittent-problem.html#ixzz3bCvn0zL2
Expert:  BOBBYSS replied 1 year ago.
This is a very possible problem. Most of the time this will cause a fuel code and not just the air flow sensor code. Did you have any other codes coming up? What was the code number?
Customer: replied 1 year ago.
there was just the one code MAF not sure about the number
Customer: replied 1 year ago.
just seems odd that it will run good till you shut it off
Expert:  BOBBYSS replied 1 year ago.
The code might help, or if your scan tool reads fuel pressure. See if the fuel pressure starts to bleed off when this occurs. If it does then the valve may be the problem. It is at the end of the fuel rail on the driver side under the glow plug module.
Customer: replied 1 year ago.
unfortunately im not able to work on truck till this weekend again its a 100 miles away. but im still digging up ideas to try to fix it. Its in a very small town.and I dont trust it to make it to a dealership. Could the MAP sensor make it act this way
Expert:  BOBBYSS replied 1 year ago.
It is possible, but not common. This engine has more fuel issues. I have had a lot of fuel pressure sensors and sensor connectors fail and cause this.
Customer: replied 1 year ago.
Hi Bobby back to working on the durmax the codes that we have are p0102 p0113 p0101 p2453 hopefully this will help Thanks
Expert:  BOBBYSS replied 1 year ago.
Thank you. From these codes it tells me that the air flow sensor may be failing and that the exhaust filter may be clogged. Typically if the exhaust filter clogs it will cause the air flow meter to read incorrectly. This filter will need to be checked and/or replaced first and then clear the codes to see if it returns.
Customer: replied 1 year ago.
Thanks Bobby, last night i took off what i think was the MAP sensor, Small sensor on passenger side right next to the plastic air cover that says 6,6 it has a tube running into air system. I think it was the MAP sensor anyway, I cleaned it up some with MAF cleaner put it back together it started right up and check engine light went off. took it for a 80 mile ride today starting and shutting it off multiple times. it started every time with no check engine light or reduced power mode. However it did act like it was going to go to reduce power mode once after starting . It idled funny just for a minute than run normal but no alarms. It seems to have good power. Does this sound like a MAP sensor. If it is will it cause it to throw MAF codes. I have heard the exhaust is suppose to clean itself is that correct. how can I tell if it is plugged.
Expert:  BOBBYSS replied 1 year ago.
It does sound like the MAP sensor and yes it can cause MAF codes. As for the exhaust filter, it is self cleaning for quite some time but at some point it needs to be replaced.

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