GM Fuel System Control Module (FSCM)

Hello Everyone
Actually I used to see FSCM on gm trucks but I still don't understand what is this module doing exactly
can any one tell us or explain for us in detail about this module ??
how is it work?
what does it do?
what the symptoms of bad one ?
how to diagnose it ?
and so on ......
Thanks

I'll take a shot at this

The GM FSCM is there primarily to run the fuel pump itself, and is responsible for maintaining the required fuel pressure (in both port injection and direct fuel injection systems). The presence of a FSCM is a sure sign that the pump is pulse width modulated. The FSCM controls both power and ground to the pump.

For reference, here's a diagram from an '08 Suburban:



What exactly happens on pin 17 to the BCM, I'm not sure, never needed to investigate. I do know that pin 13 is the ECM's command to run the pump, and is some kind of pull-up signal which can be simulated with a test light.

The fuel pressure sensor is a direct input to the FSCM, which brings us to Fuel Pump Trim. Just like regular fuel trim, the FSCM will 'trim' how hard it works the fuel pump to get the fuel pressure it's looking for. For example, a vehicle with an empty fuel tank will usually have very high short term and long term pump trims, as the FSCM has been desperately trying to get fuel pressure up.

You can find these trims in scan data, and there's specific codes associated with pump trim problems. Here's an example from a 2011 Cruze (same operation as the trucks):

www.scanshare.io/share/vykTLskcEEy3SeHzFTXrWw#2,3,5,7,8



How to spot a bad one? I've yet to run into one, personally, but I know it happens. I say treat it just like any other module Eric from SMA just did an interesting video on a FSCM problem , too, definitely worth watching.

Did that help at all? Let me know if you have more questions

Thank you very much Tyler
really you provide me useful info
before your post I was thinking the FSCM not just for fuel pump but I think it is related to fuel injector operating
the diagram you provide and video by Eric SMA really very good explain
Thank you again

No problem! The cool thing is that, as far as I know, all GM pump modules work this way. So, if you understand one, you understand them all

what about programming !
does it require online subscription to reprogramming or not ?

Yep, reprogramming subscription is required on these.

Hi guys, as far as subscription does anybody have a link to the GM site so I could do that?
Thanks, Doug

acdelcotds.com

Got it....