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Ask Juan Crespo Your Own Question
Juan Crespo
Juan Crespo, ASE Certified Technician
Category: GM
Satisfied Customers: 1513
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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My rely for fuel pump is where it's suposto be any ideas,

Customer Question

My rely for fuel pump is where it's suposto be any ideas
JA: Have you ever replaced the fuel pump, or is this the original?
Customer: It's been replaced
JA: What is the model/year of your GM?
Customer: 2008 avalanche ltz
JA: Are you fixing your Avalanche yourself? What have you tried so far?
Customer: Everything but I'm stack at no power to the fuse or fuel pump
JA: Anything else you want the mechanic to know before I connect you?
Customer: I just wanted to know that
Submitted: 2 months ago.
Category: GM
Expert:  Brad Barker replied 2 months ago.

Hi my name is ***** ***** would like to assist you. So you have no power at the fuel pump fuse in the underhood fuse box?

Customer: replied 2 months ago.
I don't have power only where the relay supost to be expected that there never been one before
Expert:  Brad Barker replied 2 months ago.

so you have power at a relay spot and you are saying it does not have a relay in it?

Customer: replied 2 months ago.
Correct,but the fuse used to work
Customer: replied 2 months ago.
I'll try that thanks.
Expert:  Brad Barker replied 2 months ago.

this is the diagram to your truck double check to make sure it is correct. If it there is no power at the fuel pump fuse or relay. I would inspect under the fuse box by removing it and looking for corroded green wires.

Customer: replied 2 months ago.
Ok is there other places that gm install relay. For the fuel pump
Expert:  Brad Barker replied 2 months ago.

no not on this vehicle it should be underhood fuse box

Expert:  Brad Barker replied 2 months ago.

find the relay?

Customer: replied 2 months ago.
No I'm tired of trying different things and I only get fuel pump circuit open in the code reading
Expert:  Brad Barker replied 2 months ago.

so getting a code for fuel pump circuit?

Customer: replied 2 months ago.
it said open circuit
Expert:  Brad Barker replied 2 months ago.

well if that relay is missing then it will be an open circuit. According to your diagram for your vehicle there should be a relay there.

Expert:  Brad Barker replied 2 months ago.

if you were positive that there was never a relay there that is odd because that vehicle should have a fuel pump relay that the pcm closes to send power to the pump when the key is turned to on position. It should click and power the pump up for 2 seconds to prime the system and keep it energized while the truck is running.

Customer: replied 2 months ago.
I am
Expert:  Brad Barker replied 2 months ago.

need to remove that fuse box and see if it is corroded underneath make sure there is no green corroded terminals on the connectors or the box. I am beginning to think that fuse box is bad or there is no crank signal to pcm.

Customer: replied 2 months ago.
I did it today and it had a little bit of corrosion, cleaned it up and put it back in, and every time I get fuel pump circuit open.
Expert:  Brad Barker replied 2 months ago.

what is the dtc p0230 or p0231

Customer: replied 2 months ago.
It's p025A
Expert:  Brad Barker replied 2 months ago.

alright only think i can think of is check for corrossion at your fuel pump control module. If corrossion is present will need to repair harness and replace module. Module could just be faulty as well have attached pic of module.

Customer: replied 2 months ago.
I'm going to replace it i just bought it but can it be possible that the ignition switch or the gas pedal are bud.
Expert:  Brad Barker replied 2 months ago.

if the ignition switch was bad other things would not be getting power as well

Customer: replied 2 months ago.
Ok that is what I thought, I replace the modular, now I get p0230 on the reading..
Expert:  Brad Barker replied 2 months ago.

there has to be a fuel pump relay missing that code is for the pcm not seeing the voltage on the relay.

Customer: replied 2 months ago.
Ok I'll have look for it, I'll let you know later today. Thanks
Expert:  Juan Crespo replied 2 months ago.

Hi there. Different expert here.

The reason why you can't find a traditional fuel pump relay on your truck is because it does not exist (see attached diagram). Your Avalanche is equipped with a fuel pressure control module or FPCM (mounted to the left side of the frame assembly, below the driver's seat) that the onboard computer (ECM) uses to activate the fuel pump on a duty-cycle basis instead of the traditional On and OFF mode of operation.

DTC P025A sets when the FPCM detects a fault on the fuel control enable signal and it is mostly caused by a bad FPCM. I'be happy to guide you through the diagnostic procedures, just be aware that you'll need to use a capable scan tool and multimeter.

Customer: replied 2 months ago.
Juan is this what you are talking about
Expert:  Juan Crespo replied 2 months ago.

Looks like it. There is a recall out on those:

Vehicle Make / Model:
2009 CHEVROLET / COLORADO
2009 GMC / CANYON

NHTSA Campaign ID Number:
09V154000

Summary:
GM IS RECALLING 27,188 MY 2009 CADILLAC ESCALADE, ESCALADE HYBRID, ESCALADE ESV, AND ESCALADE EXT; CHEVROLET AVALANCHE, SUBURBAN, TAHOE, TAHOE HYBRID, AND COLORADO; AND GMC YUKON, YUKON HYBRID, YUKON XL, AND CANYON VEHICLES. THE FUEL SYSTEM CONTROL MODULES MAY HAVE A CONDITION IN WHICH AN ADHESIVE SEPARATION OF THE ROOM TEMPERATURE VULCANIZING (RTV) SEAL BETWEEN THE SEAL AND THE HOUSING MAY ALLOW WATER TO SEEP INTO THE MODULE.

Consequence:
WATER IN THE MODULE COULD CAUSE A SHORT OR OPEN CIRCUIT, ILLUMINATION OF THE SERVICE ENGINE SOON LAMP, SETTING OF DIAGNOSTIC TROUBLE CODES OR THE ENGINE MAY BE HARD TO START, MAY NOT START OR MAY STALL INCREASING THE RISK OF A CRASH.

Remedy:
DEALERS WILL INSTALL A NEW FUEL SYSTEM CONTROL MODULE FREE OF CHARGE. THE RECALL BEGAN ON MAY 18, 2009. OWNERS MAY CONTACT CADILLAC AT 1-***-***-****, CHEVROLET AT 1-***-***-**** AND GMC AT 1-***-***-**** OR AT GM Owners Center - GM.

Notes:
GM RECALL NO. 08411. OWNERS MAY ALSO CONTACT THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION'S VEHICLE SAFETY HOTLINE AT 1-***-***-**** (TTY 1-***-***-****), OR GO TO HTTP://WWW.SAFERCAR.GOV .

Expert:  Juan Crespo replied 2 months ago.

The attached pic shows where the FPCM is mounted under the truck.

Customer: replied 2 months ago.
My truck is 2008 Chevrolet avalanche
Expert:  Juan Crespo replied 2 months ago.

They go by VIN and production date - were this my truck, I'd give them a call...

Customer: replied 2 months ago.
You are right I'll give them a call
Expert:  Juan Crespo replied 2 months ago.

I hope they take care of it for you.

Best Regards.

Customer: replied 2 months ago.
Thank you, ***** ***** not you can help me with it walking me true the proses.
Expert:  Juan Crespo replied 2 months ago.

Other than the usual R&R, the only other process needed is programming; upon installing the new FPCM, the PCM will set code P0602 and the pump won't run until the new module is programmed - as with any new module, the FPCM will need to be programmed using GM's Service Programming System with the latest calibration available on TIS2WEB through either a Tech-II or the multiple diagnostic interface (MDI) loaded with the latest software.

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