New Holland 1804 – ECU: High DPF Intake Temperature

The engine control unit has detected an excessively high temperature at the intake of the Diesel Particulate Filter (DPF). This amber-level warning indicates that the DPF inlet temperature has exceeded predefined thresholds or the sensor is reading incorrectly. Accurate temperature readings are critical for managing the DPF regeneration process where soot is burned off. If this condition persists, the system may deactivate regeneration, leading to DPF clogging and eventual engine power reduction.

• PowerStar T4.55
• PowerStar T4.65
• PowerStar T4.75
• PowerStar T4.85
• PowerStar T4.95
• PowerStar T4.105
• PowerStar T4.115
• Workmaster 60
• Workmaster 70
• FARMALL series
• T6 Series
• T6.125
• T6.180
• C227
• C327
• C332
• C337
• L223
• L321
• L328
• CX series
• Workmaster Series
• Boomer Series

1. 1

   Retrieve all fault codes to check for related temperature, pressure, or injector faults that could provide diagnostic clues

2. 2

   Analyze live data with a cold engine to ensure all exhaust temperature sensors (DOC inlet, DPF inlet, DPF outlet) read close to ambient air temperature

3. 3

   Monitor live data during engine warm-up to ensure temperatures rise smoothly and logically (DPF intake should follow DOC inlet temperature)

4. 4

   Monitor live data during a stationary regeneration (if possible) to check for erratic behavior or inverted temps (DPF outlet hotter than inlet, indicating a failing DOC)

5. 5

   Inspect the wiring harness and connectors leading to the DPF intake temperature sensor for melting, chafing, corrosion, or bent pins

6. 6

   Check the exhaust system for leaks before the DPF, which can introduce oxygen and cause premature ignition

7. 7

   Examine the sensor itself for heavy soot buildup or physical damage

1. 1

   Confirm the fault

   Use live data to confirm the DPF intake temperature sensor is providing illogical or incorrect readings (e.g., -40°C, 900°C, or a fixed value) compared to other exhaust sensors.

2. 2

   Test sensor resistance

   Disconnect the sensor and measure resistance across its pins. A healthy sensor typically reads around 19-20k Ohms when cold. An open circuit (infinite resistance) or short circuit (zero resistance) indicates a failed sensor.

3. 3

   Perform dynamic resistance test

   Warm the tip of the sensor with a heat gun while monitoring resistance. As an NTC sensor, resistance should decrease smoothly as temperature increases. Replace the sensor if resistance is erratic or unchanged.

4. 4

   Test harness voltage

   With the key on and sensor disconnected, check the harness-side connector for a 5V reference voltage and a good ground to verify ECU wiring integrity.

5. 5

   Address underlying causes

   If the sensor and wiring test correctly, the high temperature is real. Investigate actual causes of high exhaust temperatures, such as leaking fuel injectors, a faulty/washed Diesel Oxidation Catalyst (DOC), or engine performance issues causing a rich fuel mixture.

6. 6

   Replace the sensor

   If the sensor is confirmed faulty, replace the DPF intake temperature sensor threaded into the exhaust piping just before the main DPF body.

7. 7

   Clear faults and verify

   Clear all fault codes, run the machine, and monitor live data during operation and a forced regeneration cycle to ensure temperatures remain within expected ranges. Some systems may require an ECU reflash or reset after component replacement to recognize the new part.