Lost Communication with fuel Pump.

[blackdragon1]

Dear Forum
I live in Macau, near Hong Kong and have no GM service center to help me.

My 2009 H2 with 10,000 km has "Lost Communication with fuel pump" on the tech2 code U0109

After driving in heavy rain for a couple of days my "Check Engine Light" came On, then after 2 more days the car would not start in the morning.

The engine will crank ok, but Ive now confirmed I have NO fuel to the engine & NO power to fuel pump. are their any hidden fuses that I can check or areas known for wire damage. or could it be the ECU...

Any tech help would be appreciated by all.

[blackdragon1]

It looks like I need to remove / lower the fuel tank to replace the fuel pump is that correct ?

[Astroboy]

Originally Posted by blackdragon1

It looks like I need to remove / lower the fuel tank to replace the fuel pump is that correct ?

I think you're correct. The fuel pump is located in middle center of inserted into the tank from the above.

I just looked this up in the GM's official service manual (phonebook-thick, heavy, 3-volumes). The detailed instructions of how to do this procedure spans for several pages.

It seems the procedure involves:

- disconnecting the gas tank from the inlet hose which originates from the chrome fuel door.
- disconnecting the evaporation vent pipes (metal, small-diameter, long, and winding)
- dropping the entire fuel tank.
- draining the gasoline and handling care.
- removing and replacing the ruined fuel pump.

Wow, I didn't know there is so much involved.

(disclamer: I don't have a personal experience doing this, just a wannabe mechanic with manual)

I had the same experience that OP is having. One time, there was a knee-deep flood on freeway caused by busted water main. I proceeded to ford and go across this big 50-yard puddle while every other driver in regular car is inundated and stuck. They looked at me with envy. My H2 drove fine at 60 mph to my home with no hint of any malfunction. But next morning, its engine cranked but could not start and CEL came on.

I had to get my H2 towed to the dealership, and they fixed it under warranty.

The owner's manual specifies that H2 can ford water up to 20 inches, but this needs to be done at below 5 mph. Too bad, I was going faster than creating walls of splash curtains and enjoying it.

[blackdragon1]

Thanks Astroboy
This is a big help for me, I have ordered to fuel pump unit already..to try..
I also have the Service book x 3.

Yours sounds identical to me, I also was driving on flooded roads here in Macau during a small Typhoon / Hurricane at high-ish speed making huge curtains of water over the car... all day alot of fun until now. Then I drove one 1 more day before it stopped on me.

Did your dealer tell you why this would affect the fuel pump, unless water got in to the tank, I dont really understand why it would stop.Looks like a big job to drop the tank...

Any further info would be appreciated.

[blackdragon1]

Thanks Mike, from NewGMparts.com for all your email help in trying to solve my H2 fuel problem and sending me parts all the way to Macau.
Its great service like this, thats hard to find now days anywhere in the world. Keep up the good work, Reuben

[blackdragon1]

Can anyone tell me where the "Fuel Pump Relay" is located on a 2008-9 H2
I cannot seem to find it.

[HUMTECH]

[HUMTECH]

No fuel pump relay, controlled by the fuel pump flow control module

[blackdragon1]

Originally Posted by HUMTECH

No fuel pump relay, controlled by the fuel pump flow control module

Thanks HUMTECH for the electrical diagram, this is a big a help, My H2 is being towed to the workshop tomorrow. If I cannot get this fixed, Im going to have to find a good H2 mechanic in the US or (Canada) & fly him down to Macau all expenses paid...

[HUMTECH]

Ive been working on these trucks since day one of production

[blackdragon1]

Originally Posted by HUMTECH

Ive been working on these trucks since day one of production

HUMTECH I have PM you.

[blackdragon1]

Today my Mechanic got the engine started by connecting 12 volts directly two the Fuel Pump connector on the tank from another battery.
The engine idles & revs smoothly. So my fuel pump seems ok,
Im guessing I have a broken wire or ground on the fuel harness somewhere or the FPCM is stuffed.
Anyone have some ideas where to look next.

[HUMTECH]

If you cant communicate with the fpcm with the tech 2 scanner. check power and ground to the module and test the data line with an ohm meter for continuity. If all 3 are good you need a fpcm. Private messages not working right now.

[blackdragon1]

Today I opened the FPCM and it was soaking wet, with allot of visible damage on electronics board, I really thought this would be seamless plastic construction but its not, very poor design and location on the truck. see link

http://www.sandyblogs.com/techlink/2...ol-module.html

Hopefully when the new FPCM arrives my truck will start.

[blackdragon1]

We Replaced the FPCM and still cannot get the engine to start, But we now only have 1 DTC code showing on my scan tool= P0602,
Im not sure if this is related to the PCM/ECM or the new FPCM ??