• | 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 provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open | High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
Exhaust Gas Temperature Sensor 1 Signal | P0545 | P0546 | P20E2 | P0546 | P20E2 |
Exhaust Gas Temperature Sensor 1 Low Reference | -- | P0546 | P20E2 | P0546 | P20E2 |
Exhaust Gas Temperature Sensor 2 Signal | P2032 | P2033 | P20E2 | P2033 | P20E2 |
Exhaust Gas Temperature Sensor 2 Low Reference | -- | P2033 | P20E2 | P2033 | P20E2 |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage |
---|---|---|---|
Operating Conditions: Engine Running Parameter Normal Range: -39 to +999°C (-38 to +1,830°F) | |||
Exhaust Gas Temperature Sensor 1 Signal | -40°C (-40°F) | 1 000°C (1,832°F) | 1 000°C (1,832°F) |
Exhaust Gas Temperature Sensor 1 Low Reference | -- | 1 000°C (1,832°F) | 1 000°C (1,832°F) |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage |
---|---|---|---|
Operating Conditions: Engine Running Parameter Normal Range: -39 to +999°C (-38 to +1,830°F) | |||
Exhaust Gas Temperature Sensor 2 Signal | -40°C (-40°F) | 1 000°C (1,832°F) | 1 000°C (1,832°F) |
Exhaust Gas Temperature Sensor 2 Low Reference | -- | 1 000°C (1,832°F) | 1 000°C (1,832°F) |
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 5-volt 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.
• | 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. |
• | The ECM detects a temperature difference greater than 20°C (68°F) between exhaust gas temperature sensors 1 and 2. |
• | This DTC runs once per key cycle when the above condition is met. |
DTC P20E2 is a Type B DTC.
DTC P20E2 is a Type B DTC.
• | 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 . |
Diesel Particulate Filter (DPF) System Description
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
Important: Determine the ambient temperature by using an accurate thermometer.
Important: Perform the Repair Verification after completing the Circuit/System Testing.
⇒ | If the resistance is greater than the specified range, repair the open/high resistance on the affected circuit. If the circuit tests normal, replace the ECM. |
• | ECM X1 signal circuit terminal 69 to EGT sensor 1 terminal A |
• | ECM X1 signal circuit terminal 93 to EGT sensor 2 terminal A |
⇒ | If the resistance is greater than the specified range, repair the open/high resistance on the affected circuit. |
Measure and record the resistance of exhaust gas temperature (EGT) sensor 1 and sensor 2 and compare those measurements to the Temperature Versus Resistance .