2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 1963
1. Ignition OFF, disconnect the 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 fuel pump relay control circuit for a short to ground. If the circuit tests normal, replace the ECM.
6. Install a 3A fused jumper wire between the 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 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 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
P0231
DTC P0231, P0232, or P023F
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.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions)provides an overview of each diagnostic category.
DTC Descriptors
DTC P0231
- Fuel Pump Control Circuit Low Voltage
DTC P0232
- Fuel Pump Control Circuit High Voltage
DTC P023F
- Fuel Pump Control Circuit
Diagnostic Fault Information
Circuit/System Description
The engine control module (ECM) supplies voltage to the fuel pump control module when the ECM detects that the ignition is on. The voltage from
the ECM to the fuel pump control module remains active for 2 seconds, unless the engine is in crank or run. While this voltage is being received,
the fuel pump control module supplies a varying voltage to the fuel tank pump module in order to maintain the desired fuel rail pressure.
Conditions for Running the DTC
