fuel system control module problem.....

Discussion in 'Performance & Fuel' started by wmc3, Jan 25, 2012.

  1. wmc3

    wmc3 New Member

    I am having a problem with my 2008 silverado 1500, ext cab, I changed the O2 sensor,(P0056) and now it is blowing the fuse for the FSCM, fuel system control module, can anyone shed some light on this problem for me?

    99'HEARTBEAT MODERATOR Staff Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    I did some looking around for Trouble Code.....P0056, and found that there is a Service Bulletin from G.M. on the 2007" to 2010 Chevy Silverado/GMC Sierra's..... 2500.....3500HD......but it does not say anything about the Silverado 1500's??

    GM: 2007-10 Chevy Silverado 2500, 3500 HD, GMC Sierra 2500, 3500 HD (6.0L)
    Subject: MIL illumination with fault code P0056, P0060, P013C, P013D, P014A, P014B, P0157, P0158, P0160, P0161, P0430, P2272 or P2273 might be caused by damaged oxygen sensor wiring. As routed from the factory, the pigtail for Bank 2, oxygen sensor 2 might chafe against the top of the frame rail. If chaffing is discovered, the bulletin specifies that the sensor should be replaced. The new sensor wiring should be wrapped with a special electrical tape to prevent further chaffing. The bulletin includes part numbers (including the electrical tape), illustrations and instructions.

    Here is the link where the above information came from,

    Here is some more Information Regarding Trouble Code P0056,.......The P0056 is set when the ECM detects an open or shorted to ground condition on the heated oxygen sensor heater circuit,

    ......The code means that there is a problem with the heater element circuit of the heated oxygen sensor. Water getting inside the heated oxygen sensor connector can caused the heated oxygen sensor fuse to blow, which is a very common problem for this type codes. Before replacing the sensor, check for the condition of the heated oxygen sensor fuse and connectors.

    .....HO2S Heater Control Circuit Bank 2 Sensor 2 is the generic definition for the P0056; however your vehicle's manufacturer may have a different definition and information for the P0056 Code.

    ......Oxygen Sensors (O2S) or Heated Oxygen Sensors (HO2S) need to reach a minimum operating temperature of 750 degrees F to produce an accurate voltage signal. The faster the heated oxygen sensor reaches that temperature the faster the sensor will start sending an accurate signal to the Engine Control Module (ECM).

    ......In order to achieve the require temperature, a heater element is included inside the heated oxygen sensor. The ECM controls the heated oxygen sensor heater element based on signals from the engine coolant temperature and engine load. The ECM controls the heater element circuit by allowing current flow to ground.

    The ECM monitors the voltage signal received through the heater element circuit and determines the state of the circuit by comparing the voltage detected with the factory specifications.

    Last edited: Jan 25, 2012
  3. wmc3

    wmc3 New Member

    Thanks Mike, I changed the O2 sensor, it was routed the same as the 2500 +3500's, the wire was worn through. Now I have a problem with the fuse in slot 21 blowing when it is inserted into the fuse block. Slot 21 is the FSCM fuse. I am thinking I have a faulty fuel sending unit, do you (or anyone here), know if this would also be considered the FSCM? Fuel system control module, a fancy name for sending unit? Where would the fuel module be on my truck?
    Last edited: Jan 25, 2012

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