New Holland ENG 1805 – ISM-IDI ENGINE: Diesel Oxidation Catalyst (DOC) IN Temperature is not correct

The engine control system has detected that the temperature reading from the exhaust gas temperature sensor located at the inlet of the Diesel Oxidation Catalyst is implausible, out of its expected operating range, or reading abnormally high.

• L213
• L215
• L216
• L218
• L220
• L223
• L225
• L230
• L313
• L316
• L318
• L320
• C227
• C232
• C238
• C327
• C332
• C338
• SR130
• SR160
• SR175
• SV185
• TR270

1. 1

   Visual Inspection: Inspect the DOC intake temperature sensor wiring harness and connector for melting, chafing, or heat degradation.

2. 2

   Cold Engine Verification: Connect a diagnostic scan tool and check the live data for the DOC IN temperature when the machine has been sitting overnight. The reading should closely match the ambient air temperature and the engine coolant temperature.

3. 3

   Circuit Testing: Disconnect the sensor and check the resistance across the sensor pins with a multimeter. Compare the reading against OEM specifications. Check the harness side for proper reference voltage (usually 5V) and a good ground.

4. 4

   Exhaust Leak Check: Inspect the exhaust piping upstream of the DOC for leaks, which can draw in ambient air and skew the temperature readings.

1. 1

   Safety First

   Ensure the machine is parked on a level surface, the engine is turned off, and the key is removed. Allow the exhaust system and DOC to cool completely, as these components reach extremely high temperatures during operation.

2. 2

   Locate the Sensor

   Find the DOC IN temperature sensor. It is threaded into the exhaust pipe immediately upstream of the Diesel Oxidation Catalyst canister.

3. 3

   Disconnect Wiring

   Carefully unplug the electrical connector from the sensor harness. Inspect the chassis-side connector for corrosion or melted pins; repair if necessary.

4. 4

   Remove the Sensor

   Spray the base of the sensor with penetrating oil and allow it to soak (exhaust sensors are prone to seizing). Use a properly sized wrench or an O2/EGT sensor socket to carefully unthread the sensor from the exhaust bung.

5. 5

   Prepare the New Sensor

   Apply a small amount of high-temperature anti-seize compound to the threads of the new sensor (if it does not come pre-applied). Caution: Do not get any anti-seize on the sensor probe tip.

6. 6

   Install the New Sensor

   Thread the new sensor into the exhaust bung by hand to prevent cross-threading, then tighten it to the OEM torque specification.

7. 7

   Reconnect

   Plug the electrical connector back into the machine's harness and secure any loose wire routing away from direct heat sources.

8. 8

   Clear Codes and Test

   Connect a diagnostic tool (such as the New Holland Electronic Service Tool) to clear the ENG 1805 fault code. Start the engine, monitor the DOC IN temperature via live data, and perform a stationary regeneration if required by the ECU to verify the repair.