2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2537
DTC P2636
- Fuel Pump 2 Flow Insufficient
Circuit/System Description
The secondary fuel pump is located in the rear fuel tank. The secondary fuel pump is powered by a secondary fuel pump relay. Fuel is transferred
from the rear fuel tank to the front fuel tank in order to ensure all of the usable fuel volume is available to the primary fuel pump. The secondary
fuel pump relay is controlled by the engine control module (ECM). If the engine is running the secondary fuel pump is normally ON.
Conditions for Running the DTC
* The engine is running.
* The vehicle speed is 0 km/h (0 mph).
* The ignition voltage is between 9-18 volts.
* The transfer pump is activated.
* A slosh delay of 20 seconds has passed.
* DTC P2636 runs continuously when the above conditions are met.
Conditions for Setting the DTC
The ECM does not detect a change of 3 L (0.7925 gal), in both the primary and the secondary fuel level sensors, with the secondary pump
commanded ON for 200 seconds.
Action Taken When the DTC Sets
DTC P2636 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P2636 is a Type B DTC.
Reference Information
Schematic Reference
Engine Controls Schematics (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Special Tools
J 43244 Relay Puller Pliers
Circuit/System Verification
Important: An open or a short to voltage in the control circuit will cause both the Ckt. Open Test Status and the Ckt. Short Volts Test
Status parameters to display Fault.
Ignition ON, command the fuel pump relay ON and OFF with a scan tool while observing the following control circuit status parameters:
* Fuel Pump Relay Ckt. Short Gnd Test Status
* Fuel Pump Relay Ckt. Open Test Status
