VIN 6
DTC P040C or P040D
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) provide an overview of each diagnostic category.
DTC Descriptors
DTC P040C
- Exhaust Gas Recirculation (EGR) Temperature Sensor 1 Circuit Low Voltage
DTC P040D
- Exhaust Gas Recirculation (EGR) Temperature Sensor 1 Circuit High Voltage
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The exhaust gas recirculation (EGR) temperature sensors are variable resistors that measure the temperature of the exhaust gas at the inlet and outlet of the EGR cooler. The engine control module (ECM) supplies 5 volts to the EGR temperature sensor signal circuit and a ground for the low reference circuit. When the EGR temperature sensor is cold, the sensor resistance is high. When the EGR temperature increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a higher voltage on the EGR temperature signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the EGR temperature signal circuit.
Conditions for Running the DTC
P040C
* The engine is running for 30 seconds or longer.
* The engine coolant temperature is 60°C (140°F) or warmer.
* The engine is not in diesel particulate filter (DPF) regeneration.
* This DTC runs continuously when the above conditions are met.
* The EGR valve is open more than 4 percent.
P040D
* The engine is running for 30 seconds or longer.
* The engine coolant temperature is 60°C (140°F) or warmer.
* This DTC runs continuously when the above conditions are met.
* The EGR valve is open more than 4 percent.
Conditions for Setting the DTC
P040C
The ECM detects that the EGR temperature sensor is less than 0.26 volts for 3 seconds or longer.
P040D
The ECM detects that the EGR temperature sensor is greater than 4.9 volts for 3 seconds or longer.
Action Taken When the DTC Sets
DTCs P040C and P040D are Type A DTCs.
Conditions for Clearing the DTC
DTCs P040C and P040D are Type A DTCs.
Diagnostic Aids
* Inspect the EGR temperature sensor terminals for corrosion.
* If the EGR temperature sensor 1 signal circuit is shorted to a separate 5-volt source, the DTC will set.
* EGR temperature sensors may fail while operating under extreme temperatures. Review the Freeze Frame/Failure Records to verify the failure criteria.
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 (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, engine OFF, clear the DTCs.
2. Observe the scan tool EGR cooler temperature Sensor 1 parameter. The reading should be within the normal range -32°C to +899°C (-25.6°F to +1650°F), depending on the current ambient temperature and the vehicle operating conditions.
3. Engine running, observe the DTC information with a scan tool. DTCs P040C or P040D should not be set.
4. 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.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the EGR temperature sensor 1.
2. Ignition OFF for 90 seconds, test for less than 5 ohms between the low reference circuit terminal B and ground.
• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, verify the scan tool EGR cooler temperature Sensor 1 parameter is -33°C (-27.4°F) or colder.
• If warmer more than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the ECM.
4. Install a 3A fused jumper wire between the signal circuit terminal A and a good ground. Verify the scan tool EGR cooler temperature sensor 1 parameter is 899°C (1650°F) or warmer.
• If colder than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
5. If all circuits test normal, test or replace the sensor.
Component Testing
Measure and record the resistance of the EGR temperature sensor 1 and compare those measurements to the Temperature Versus Resistance (Fuel Temperature Sensor) (Temperature Versus Resistance (Fuel Temperature Sensor)) Temperature Versus Resistance (ECT Sensors) (Temperature Versus Resistance (ECT Sensors)) Temperature Versus Resistance (IAT Sensor 1) (Temperature Versus Resistance (IAT Sensor 1)) Temperature Versus Resistance (IAT Sensor 2) (Temperature Versus Resistance (IAT Sensor 2)) Temperature Versus Resistance (EGT Sensors) (Temperature Versus Resistance (EGT Sensors)) Temperature Versus Resistance (EGR Temperature Sensors) (Temperature Versus Resistance (EGR Temperature Sensors)).
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Engine Control Module Replacement (Service and Repair)
* Exhaust Gas Recirculation Valve Temperature Sensor Replacement - Position 1 (Exhaust Gas Recirculation Valve Temperature Sensor Replacement - Position 1)
* Control Module References (Programming and Relearning) for ECM replacement, setup, and programming