VIN 6
DTC P0545 or P0546
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 P0545
- Exhaust Temperature Sensor 1 (EGT-1) Circuit Low Voltage
DTC P0546
- Exhaust Temperature Sensor 1 (EGT-1) Circuit High Voltage
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The exhaust gas temperature (EGT) sensors are variable resistors that measure the temperature of the exhaust at the inlet and outlet of the diesel particulate filter (DPF). The engine control module (ECM) supplies a bias 5V signal to the EGT signal circuit, and supplies a ground to the low reference circuit. When the EGT is cold, the sensor resistance is low. When the EGT temperature increases, the sensor resistance increases.
Conditions for Running the DTC
* The ignition is ON.
* This DTC runs continuously when the above condition is met.
Conditions for Setting the DTC
P0545
The ECM detects that the EGT sensor is less than 0.32V for greater than 1 second.
P0546
The ECM detects that the EGT sensor is greater than 3.37V for greater than 1 second.
Action Taken When the DTC Sets
* DTCs P0545 and P0546 are Type A DTCs.
* DPF regeneration will be inhibited.
Conditions for Clearing the DTC
DTCs P0545 and P0546 are Type A DTCs.
Diagnostic Aids
* Inspect the EGT sensor terminals for corrosion.
* Measure and record the resistance of the EGT sensor at various ambient temperatures greater than -8°C (+18°F), then 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)).
* EGT sensors may fail while operating under extreme temperatures. Review the Freeze Frame Failure Records to verify the failure criteria.
* A short to a separate 5V source occurs, this DTC will set.
Reference Information
Schematic Reference
Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Diesel Particulate Filter (DPF) System Description (Diesel Particulate Filter (DPF) System)
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
Special Tools
J 25070 Heat Gun 500-750°F
Circuit/System Verification
1. Engine running, observe the scan tool EGT Sensor 1 parameter. The reading should be within the normal range -39 to +999°C (-38 to +1,830°F), depending on the current ambient temperature and the vehicle operating conditions.
2. Operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Note: Perform the Repair Verification after performing the Circuit/System Testing.
1. Ignition OFF, disconnect the harness connector at the EGT sensor 1.
2. Ignition OFF and scan tool disconnected for 90 seconds, test for less than 5 ohm 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 EGT Sensor 1 parameter is greater than 998°C (1,828°F).
• If less than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the ECM.
Note: If a short to voltage is found on the EGT signal circuit, the 3A fuse in the jumper wire will open.
4. Install a 3A fused jumper wire between the signal circuit terminal A and a good ground. Verify the scan tool EGT parameter is less than -35°C (-31°F).
• If warmer 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
Note: You must perform the Circuit/System Testing in order to verify the integrity of the EGT sensor circuits before proceeding with the Component Testing.
To simulate a high temperature failure condition, heat the sensor with the J 25070 while measuring and recording the resistance. 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)).
While monitoring the DMM, manipulate the sensor harness under varying temperature conditions to help duplicate an intermittent condition.
If a heat gun is unavailable, a high temperature condition may be achieved by test driving the vehicle at normal operating temperature while monitoring the scan tool EGT Sensor 1 and 2 parameters.
Repair Instructions
* Diesel Particulate Filter (DPF) Regeneration Enable (Diesel Particulate Filter (DPF) Regeneration Enable)
* Exhaust Temperature Sensor Replacement - Position 1 (Exhaust Temperature Sensor Replacement - Position 1)
* Engine Control Module Replacement (Service and Repair)
Repair Verification
1. Install any components or connectors that have been removed or replaced during diagnosis.
2. Perform any adjustment, programming, or setup procedures that are required when a component or module is removed or replaced.
3. Clear the DTCs.
4. Turn OFF the ignition for 90 seconds.
5. Duplicate the Conditions for Running the DTC and use the freeze Frame/Failure Records, if applicable, in order to verify the DTC does not reset. If the DTC resets or another DTC is present, refer to the Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle) and perform the appropriate diagnostic procedure.
6. Perform the Diesel Particulate Filter (DPF) Service Regeneration (Diesel Particulate Filter (DPF) Service Regeneration).