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ecmb fuse

pdmac

Full Member
Joined
May 26, 2002
Messages
10
A year ago had ecmb fuse blow while on trip in my 2002. Dealer replaced and said had no idea why it blew. Had fuse blow 3 times today in Lake of Ozarks holiday traffic. Anyone have simil ??? ??? ???ar problm. Truck won't start and power door lock don't automatically unlock when key is shut off. Help
 
The ECM B fuse in the 02 is for the Fuel Pump Relay and the Powertrain Control Module (PCM).

I have no idea if you understand this diagram, however here is the circuit.

Also, did you mount anything on the floorboard (driver side) where a screw may have extended a bit too far?

The wiring to the fuel pump may have an "injury" or wear-through and the short blows the fuse. All sorts of places that you just need to isolate.

The image expands; how, depends on your browser.
 

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Thanks Sperry. I will definitely check. The dealerships kind of scratched their heads and that was it. I appreciate the reply.
 
also check the oil pressure sending unit,pull the plug that connects to it.
 
I have a 02 chevey and about a month ago it just went completly dead goin down the rod so i took it in and the said it blue the fuil pump fuse. so the re placed it and said the dont know why it did it . so it worked fine fro awile but then starterd blowin them agin so i just kep replacing them becuse it would work for a wile but now its got to the poin to wear as soon as u put it in ad start it up it blows does eny one know why it dosent read no codes ether :E:
 
Electrical short somewhere
 
My 02 Avalanche has the same problem. it's keeps blowing the ECM fuse :help:
could it be in the  ignition switch ?
 
Ign switch faults are when the contacts become resistive or intermittent open circuit due to wear and/or contamination (dirty).

The ECM-B fuse in the 02 sources the fuel pump relay contacts and the powertrain control module. It is not part of any ign switch circuit.

If the fuse blows as soon as you replace it, pull the fuel pump relay and try it again. Then if it doesn't with the relay out, it's the relay itself (all while the ign is off).

If it blows when the ign is on only,  the fuel pump or the fuel pump wiring has a short.

There could be conditions where the relay can have a mechanical defect in a way that it could blow a fuse when it's activated only. Kind of rare but easier to isolate by swapping same p/n relays and replacing fuses or using test circuit breakers. `Get's a bit complicated to explain. :(

HTH :)
 
Ok I know this is a old thread but I am having the same problem with my 02 AV. My Ecmb fuse keeps blowing and I cannot figure out what is wrong. I think I checked all the wires none of them are corroded, I replaced the fuel pump relay, and checked the 2 grounds coming off the battery and 2 that are on the frame rail going to the fuel tank. If anyone knows what might be causing this PLEASE let me know I've been reading that this is happening to other AV's but no one has put the solution to the problem? I don't know what else to look at it reads no codes and I can't afford to take it to the dealer right now cause they want it for 2 full days at $90.00/Hr just to diagnose it which is just crazy!  At first it was happening at every 1/4 of a gas tank, then at 1/2 tank I don't know if this is just a coincidence or not, and it happens within 5 minutes of driving. I REALLY appreciate any help, Thanks in advance!!!!
 
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