P2401

DTC P2400-P2402

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors
DTC P2400
- Evaporative Emission (EVAP) System Leak Detection Pump Control Circuit

DTC P2401
- Evaporative Emission (EVAP) System Leak Detection Pump Control Circuit Low Voltage

DTC P2402
- Evaporative Emission (EVAP) System Leak Detection Pump Control Circuit High Voltage

Diagnostic Fault Information






Circuit/System Description

Battery voltage is supplied to the evaporative emission (EVAP) system leak detection pump. The ECM grounds the EVAP leak detection pump control circuit through an internal switch called a driver. The ECM monitors the status of the driver. A scan tool will display the commanded state of the EVAP leak detection pump as ON or OFF.

Conditions for Running the DTC

* The ignition is ON.
* The system voltage is at least 11 V.
* The devices have to be in their commanded state.
* P2400, P2401 and P2402 run continuously when the above conditions are met.

Note: Indeterminate state will display if the device is not in a commanded state. This is not to be considered a failure. Use the scan tool to exercise the device.

Conditions for Setting the DTC

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for a minimum of 5 s.

Action Taken When the DTC Sets

DTCs P2400, P2401 and P2402 are Type B DTCs.

Conditions for Clearing the DTC

DTCs P2400, P2401 and P2402 are Type B DTCs.

Diagnostic Aids

The EVAP leak detection pump is very quiet. You might feel it running rather than hear it.

Reference Information
Schematic Reference

Engine Controls Schematics [1][2]Electrical Diagrams
Description and Operation

Evaporative Emission Control System Description Evaporative Emission Control System Description

Hybrid Modes of Operation Description Hybrid Modes of Operation Description
Electrical Information Reference

* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

1. Service Mode active, command the EVAP leak detection pump ON and OFF with a scan tool.
2. Listen for the motor to run when commanded.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Note: This EVAP leak detection pump is very quiet. You might feel it running rather than hear it.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the Q63 evaporative emission system leak detection pump.
2. Service Mode active, verify that a test lamp illuminates between the voltage supply circuit terminal 3 and ground.

• If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the voltage supply circuit fuse is not open, test all components connected to the voltage supply circuit and replace as necessary.

3. Connect a test lamp between the voltage supply circuit terminal 3 and the control circuit terminal 4.
4. Command the Q63 evaporative emission system leak detection pump ON and OFF. The test lamp should respond to the command.

• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 engine control module.
• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.

5. If all circuits test normal, test or replace the evaporative emission system leak detection pump.

Repair Instructions

* Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Evaporative Emission System Vacuum Leak Detection Pump Replacement Service and Repair
* Control Module References Control Module References for ECM replacement, setup, and programming