P040C

DTC PO4OC Exhaust Gas Recirculation (EGR) Temperature Sensor Circuit 1 Low Voltage

Circuit Description

The exhaust gas recirculation (EGR) gas temperature sensor 1 is installed to the EGR cooler adapter. The EGR gas temperature sensor 1 is a variable resistor and it measures the temperature of the exhaust gas inlet of primary EGR cooler. The sensor has a signal circuit and a low reference circuit. The ECM supplies 5 volts to the signal circuit and a ground for the low reference circuit. When the EGR gas temperature sensor 1 is cold the sensor resistance is high. When the exhaust temperature increases the sensor resistance decreases. With higher sensor resistance the ECM detects a high voltage on the signal circuit. With lower sensor resistance the ECM detects a lower voltage on the signal circuit. If the ECM detects an excessively low signal voltage this DTC will set.

Condition for Running the DTC

^ DTC PO4OD is not set.
^ The battery voltage is between 10 to 16 volts.
^ The ignition switch is ON.

Condition for Setting the DTC

^ The ECM detects that the EGR gas temperature sensor 1 (inlet of primary EGR cooler) signal voltage is less than 0.1 volts for 1 second.

Action Taken When the DTC Sets

^ The ECM illuminates the MIL when the diagnostic runs and fails. Refer to DTC Type Definitions for Action Taken When the DTC Sets - Type A.
^ The ECM inhibits EGR control.

Condition for Clearing the DTC

^ Refer to DTC Type Definitions for Condition for Clearing the MIL/DTC - Type A.

Diagnostic Aids

^ If an intermittent condition is suspected refer to Intermittent Conditions in this section.
^ Use the Temperature vs. Resistance table to test the EGR gas temperature sensor 1 at various temperature levels to evaluate the possibility of a skewed sensor.

Circuit/System Testing DTC PO4OC