P2493
DTC P2493
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 P2493
- Exhaust Gas Recirculation (EGR) Cooler Bypass Position Sensor Performance
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The Engine Control Module (ECM) uses the Exhaust Gas Recirculation (EGR) cooler bypass valve position sensor to determine the position of the bypass valve. The ECM sends a reference voltage through the 5-volt reference circuit to the position sensor. The ECM provides a voltage return path for the sensor through the low reference circuit. A variable voltage signal, based on the valve position, is sent from the sensor to the ECM through the position sensor signal circuit. The ECM compares the actual bypass valve position with the desired bypass valve position when the valve is commanded open or closed.
The EGR cooler bypass valve is controlled by the ECM through the bypass valve motor high control and low control circuits. The ECM supplies voltage that is near ignition voltage to the high and low control circuits at all times. The ECM will pulse width modulate the low control circuit to ground when EGR cooler bypass is desired.
Conditions for Running the DTC
* The Engine speed is greater than 100 RPM.
* The Engine Coolant Temperature (ECT) is greater than -11°C (19.4°F).
* The EGR cooler bypass valve is active.
* The EGR cooler bypass valve offset learning from the previous drive cycle is complete.
* The EGR cooler bypass offset learning is not active.
* DTC P2493 runs continuously when the above conditions have been met.
Conditions for Setting the DTC
The ECM detects that the difference between the actual EGR cooler bypass position and the desired EGR cooler bypass position is greater than 10 % or less than -10 % for greater than 8 s.
Action Taken When the DTC Sets
DTC P2493 is a Type B DTC.
Conditions for Clearing the DTC
DTC P2493 is a Type B DTC.
Reference Information
Schematic Reference
Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
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. Ignition ON, observe the scan tool Des EGR Cooler Bypass Vlv Position and the EGR Cooler Bypass Vlv Position Sensor parameters. Command the EGR Cooler Bypass Valve from 0 to 100 % with a scan tool. The parameters should respond and remain within 3 % throughout the commanded range.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Ignition OFF, remove the Q47 EGR cooler bypass solenoid valve. Refer to Exhaust Gas Recirculation Cooler Bypass Valve Replacement (Service and Repair). Inspect the Q47 EGR cooler bypass solenoid valve for the following conditions:
* A sticking, binding or frozen EGR cooler bypass solenoid valve
* Any coking, soot build up, debris or damage that can cause the valve to stick partially open or closed
• If a condition is found, clean or replace the Q47 EGR cooler bypass solenoid valve as necessary.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Exhaust Gas Recirculation Cooler Bypass Valve Replacement (Service and Repair)
* Control Module References (Control Module References) for ECM replacement, setup and programming