Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provide an overview of each diagnostic category. |
DTC Descriptors
DTC P040C: Exhaust Gas Recirculation (EGR) Temperature Sensor 1 Circuit Low VoltageDTC P040D: Exhaust Gas Recirculation (EGR) Temperature Sensor 1 Circuit High Voltage
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
EGR Temperature Sensor 1 Signal | P040C | P040D, P040F | P040D | P040F |
EGR Temperature Sensor 1 Low Reference | -- | P040D, P040F | -- | P040F |
Typical Scan Tool Data
Circuit | Short to Ground | Open/High Resistance | Short to Voltage |
|---|---|---|---|
Operating Conditions: Ignition ON, engine OFF Parameter Normal Range: Varies depending on current ambient temperature and the vehicle operating conditions | |||
EGR Temperature Sensor 1 Signal | 900°C (1652°F) | -35°C (-31°F) | -33°C (-27.4°F) |
EGR Temperature Sensor 1 Low Reference | -- | -35°C (-31°F) | -- |
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. |
| • | The engine coolant temperature is more than 60°C (140°F). |
| • | The engine is not in 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. |
| • | The engine coolant temperature is more than 60°C (140°F). |
| • | 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 more than 1 second.
P040D
The ECM detects that the EGR temperature sensor is greater than 4.9 volts for more than 1 second.
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
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, engine OFF, clear the DTCs.
- 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.
- Engine running, observe the DTC information with a scan tool. DTCs P040C or P040D should not be set.
- 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
- Ignition OFF, disconnect the harness connector at the EGR temperature sensor 1.
- Ignition OFF for 90 seconds, test for less than 5 ohms between the low reference circuit terminal B and ground.
- Ignition ON, verify the scan tool EGR cooler temperature Sensor 1 parameter is -33°C (-27.4°F) or colder.
- 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 all circuits test normal, test or replace the sensor.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | 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. |
| ⇒ | 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. |
Component Testing
Measure and record the resistance of the EGR temperature sensor 1 and compare those measurements to the Temperature Versus Resistance .
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for ECM replacement, setup, and programming |
