GM 13506688 Fuel Pump

To remove the secondary fuel tank module, start by detaching the cable from the negative battery terminal and relieving the fuel system pressure. Then, remove the fuel tank from the vehicle and spray the tangs of the module lock ring with penetrating oil. Disconnect the EVAP hose quick-connect fitting on the top of the module and use water pump pliers to remove the lock ring. If it's stuck, tap it with a hammer and brass punch. Disconnect the electrical connector and release the suction port tube to carefully pull out the module. For installation, inspect the o-ring and replace if necessary, then reverse the removal steps. To remove the primary fuel tank module, disconnect all electrical connectors from the module and pressure sensor. Use water pump pliers to remove the module lock ring, tapping it if needed. Release the lines from the top of the tank and carefully remove the module. Inspect the o-ring and replace if deteriorated, then install by reversing the removal process.