P20E2
DTC P20E2
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) provides an overview of each diagnostic category.
DTC Descriptor
DTC P20E2
- Exhaust Temperature Sensor 1-2 Correlation
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The exhaust gas temperature sensors are variable resistors that measure the temperature of the exhaust gas 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 sensor is cold, the sensor resistance is low. When the EGT temperature increases, the sensor resistance increases. With high sensor resistance, the ECM detects a higher voltage on the EGT signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the EGT signal circuit.
Conditions for Running the DTC
* DTCs P0545, P0546, P2032, P2033 are not set.
* The engine has been OFF for greater than 5 hours.
* The engine is running.
* The ambient temperature is greater than 10°C (50°F).
* DTC P20E2 runs once per key cycle within the above enabling conditions.
Conditions for Setting the DTC
* The ECM detects at initial power-up, a temperature difference of greater than 20°C (36°F), exists between exhaust gas temperature sensors 1 and 2.
* This DTC runs once per key cycle when the above condition is met.
Action Taken When the DTC Sets
DTC P20E2 is a Type B DTC.
Conditions for Clearing the DTC
DTC P20E2 is a Type B DTC.
Diagnostic Aids
* A slight to moderate resistance in either signal or low reference circuit, can widen the spread between the two EGT sensors, and cause this DTC to set.
* An EGT sensor that is skewed lower at various ambient temperatures, due to more resistance than is normal, can widen the spread between the two sensors and cause this DTC to set. Measure and record the resistance of both EGT sensors 1 and 2 at ambient temperature. 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)).
Reference Information
Schematic Reference
Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Diesel Particulate Filter (DPF) System Description (Description and Operation)
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
Note: Determine the ambient temperature by using an accurate thermometer.
1. If the ignition has been OFF for greater than 5 hours, determine which EGT sensor is skewed by comparing EGT Sensor 1 and 2 parameters to the ambient temperature with a scan tool. The readings should be within 19°C (34°F) of each other and also the ambient temperature.
2. Ignition ON, observe the scan tool EGT Sensor 1 and 2 parameters. The readings should be between -40 to +999°C (-38 to +1,830°F) depending on the current ambient temperature and the vehicle operating conditions
3. 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
Note: Perform the Repair Verification after completing the Circuit/System Testing.
1. Ignition OFF, disconnect both harness connectors at EGT sensor 1 and sensor 2.
2. Ignition OFF and scan tool disconnected for 90 seconds, Measure for a resistance of less than 5 ohm on each low reference circuit between terminals B and ground.
• If greater than the specified range, repair the open/high resistance on the affected circuit. If the circuit tests normal, replace the ECM.
3. Ignition OFF, disconnect the X1 harness connector at the ECM.
4. Test for less than 5 ohm between the signal circuit terminal A of the EGT sensor 1 and the corresponding terminal 69 X1 of the ECM.
• If greater than the specified range, repair the open/high resistance in the circuit.
5. Test for less than 5 ohm between the signal circuit terminal A of the EGT sensor 2 and the corresponding terminal 93 X1 of the ECM.
• If greater than the specified range, repair the open/high resistance in the circuit.
6. If all circuits test normal, test or replace the affected sensor.
Component Testing
Measure and record the resistance of exhaust gas temperature (EGT) sensor 1 and sensor 2 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
* Diesel Particulate Filter (DPF) Regeneration Enable (Diesel Particulate Filter (DPF) Regeneration Enable)
* Exhaust Temperature Sensor Replacement - Position 1 (Exhaust Temperature Sensor Replacement - Position 1)
* Exhaust Temperature Sensor Replacement - Position 2 (Exhaust Temperature Sensor Replacement - Position 2)
* 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 60 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. To avoid the customer's return to the service department, perform the Diesel Particulate Filter (DPF) Regeneration Enable (Diesel Particulate Filter (DPF) Regeneration Enable).