PCM B 20A fuse blows out.


DuckSauce
01-27-2009, 09:46 PM
Im driving and all of the sudden the PCM B 20A fuse blows ; ABS light comes, on fuel pressure is cut off, the gas gauge goes dead, the shifting indicator disappears, the info screen flashes break system failure. I replace it and drive again. then about a mile later it blows again.

DuckSauce
01-27-2009, 10:07 PM
Sorry I should have mentioned its a 2004 Tahoe Z71 Sorry again im a noob.

discnik
01-27-2009, 11:40 PM
There are several earlier posts, (2006) , concerning a bad fuel relay and possibly bad fuel pump or fuel system wiring shorting.

It seems to me there was a new wiring kit to install when replacing Chevy fuel pump modules, but I can not find the reference to it. Sorry.

It does seem according the wiring diagram for your vehicle is in the system that the fuse protects. Would be worth checking out the fuel system wiring.

j cAT
01-28-2009, 10:55 AM
Sorry I should have mentioned its a 2004 Tahoe Z71 Sorry again im a noob.

as mentioned this fuse goes to the relay CONTACTS that send 12volts to the fuel pump...but this fuse also goes to the computer,,,ecm/pcm...since this is intermittent I would open up the pcm coverings and carefully inspect all wiring that goes into the computer mounted on the driverside of the engine bay...vermin/rats/mice can also be a cause...chewing on the wires...also any wire [gray] that goes to/from the fuel pump/fuel pump relay...


let us know what was found..especially if the wire was damaged due to chaffing...

DuckSauce
02-04-2009, 07:16 AM
Thanksa whole bunch everyone I REALLY APPRECIATE the help.

It turns out both the fuel pump and the relay where shorting out causing the blown fuse. Replaced both and the tahoe is back in good shape.

Thanks again.
sincerely
Angel aka DuckSauce

j cAT
02-04-2009, 07:59 PM
Thanksa whole bunch everyone I REALLY APPRECIATE the help.

It turns out both the fuel pump and the relay where shorting out causing the blown fuse. Replaced both and the tahoe is back in good shape.

Thanks again.
sincerely
Angel aka DuckSauce

I don't know how the relay could short out but since the replacing of the fuel pump stopped the fuse from blowing replacing the relay is a no brainer....whenever the pump fails this way or the vehicle has a lot of miles its safe to replace the relay as well..........good luck ..thanks for your input.

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