2010 Cadillac Truck Escalade RWD V8-6.2L Page 2534
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
- Fuel Pump Relay Ckt. Short Volts Test Status
* Each parameter should toggle between OK and Not Run or Not Run and OK.
Circuit/System Testing
1. Ignition OFF, disconnect the secondary fuel pump relay.
2. Ignition ON, verify that a test lamp illuminates between the ground circuit terminal and B+.
瀚慖f the test lamp does not illuminate, test the ground circuit for a short to voltage or an open/high resistance.
3. Verify that a test lamp does not illuminate between the ground circuit terminal and the control circuit terminal.
瀚慖f the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
4. Remove the test lamp.
5. Command the fuel pump relay ON with a scan tool. Verify the scan tool fuel pump relay Ckt. Short Grnd Test Status parameter is OK.
瀚慖f not the specified value, test the secondary fuel pump relay control circuit for a short to ground. If the circuit tests normal, replace the
ECM.
6. Install a 3 A fused jumper wire between the secondary fuel pump relay control circuit terminal and the ground circuit terminal. Command the
fuel pump ON with a scan tool. Verify the scan tool fuel pump relay Ckt. Short Grnd Test Status parameter is Fault.
瀚慖f not the specified value, test the secondary fuel pump relay control circuit for an open/high resistance. If the circuit tests normal, replace
the ECM.
7. If all circuits test normal, test or replace the secondary fuel pump relay.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Relay Replacement (Attached to Wire Harness) (See: Power and Ground Distribution/Power Distribution Relay/Service and Repair/Relay
Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (See: Power and Ground Distribution/Power
Distribution Relay/Service and Repair/Relay Replacement (Within an Electrical Center))
* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup and programming
P2635
DTC P2635
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
