The code for a 6. 7 is P040B. You will need a scan tool to diagnose it properly.
Theory of Operation
The Exhaust Gas Recirculation (EGR) Outlet Temperature Sensor is a variable resistor sensor and is used to measure the temperature of the EGR gas flow after it exits the EGR cooler. The Engine Control Module (ECM) supplies 5-volts to the exhaust gas recirculation temperature signal circuit. The ECM monitors the change in voltage caused by changes in the resistance of the sensor to determine the EGR outlet temperature. There are two rationality tests. Key-on and engine running. The key-on test fails if the EGR Outlet Temperature Sensor value is different than the key on temperature estimate by more than a calibrated threshold. The engine running test fails if the EGR Outlet Temperature Sensor value does not change by more than a calibrated threshold, over a calibrated period of time. If this fault becomes active the ECM will light the MIL light immediately. During this time the EGR valve will be closed. The ECM turns off the MIL when the diagnostic runs and passes in four consecutive drive cycles.
When Monitored:
EGR Outlet Temperature and exhaust temperature below a calibrated range at key on.
Set Condition:
The key-on test fails if the EGR Outlet Temperature Sensor value is different than the key on temperature estimate by more than a calibrated threshold. The engine running test fails if the EGR Outlet Temperature Sensor value does not change by more than a calibrated threshold, over a calibrated period of time.
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