New Holland DCU 19011 – DCU: Temperature sensor after catalyst (electrical) | signal low | Catalyst Temperature Sensor Circuit Low

The voltage signal coming from the Exhaust Gas Temperature (EGT) sensor located downstream of the SCR catalyst is falling below the minimum acceptable threshold, indicating a short to ground in the sensor's wiring circuit, a disconnected plug, or an internally failed sensor.

• T6
• T7
• T8
• T9
• W110C
• W190B
• Magnum
• Puma
• Optum

1. 1

   Visually inspect the temperature sensor wiring harness (located after the SCR catalyst) for melted insulation, chafing against the chassis, or pinched wires that could cause a short to ground.

2. 2

   Disconnect the sensor and check the connector pins for corrosion, moisture, or pushed-out terminals.

3. 3

   Using a multimeter, check the sensor's signal wire for continuity to ground and verify that the DCU is supplying the correct 5V reference voltage to the sensor connector when the key is ON.

4. 4

   Measure the resistance across the sensor's pins at room temperature. A reading of 0 ohms (dead short) or infinite ohms (open circuit) indicates the sensor has failed internally.

1. 1

   Preparation

   Turn off the engine and allow the exhaust system to cool completely. Turn off the battery master disconnect switch.

2. 2

   Locate the Sensor

   Find the exhaust temperature sensor positioned downstream of the SCR catalyst.

3. 3

   Disconnect Wiring

   Unplug the electrical connector from the sensor to the main machine harness.

4. 4

   Remove the Sensor

   Using a flare-nut wrench or O2 sensor socket, carefully unscrew the sensor from the exhaust pipe. Note: Exhaust sensors frequently seize; apply penetrating oil and allow it to soak if the sensor is stuck.

5. 5

   Install the New Sensor

   Apply a small amount of high-temperature anti-seize compound to the threads of the new sensor (avoid getting any on the sensor probe itself). Thread it in by hand to prevent cross-threading, then tighten to the OEM torque specification.

6. 6

   Reconnect

   Plug the electrical connector back in. Ensure the wiring is routed safely away from the hot exhaust pipe and secured with zip ties if necessary.

7. 7

   Clear Codes

   Turn the battery disconnect back on. Connect a diagnostic tool (such as the CNH Electronic Service Tool) to clear the DCU 19011 / P042C fault code.

8. 8

   Validation

   Start the engine and monitor the exhaust temperature data via the diagnostic tool or the in-cab AFS/IntelliView display to ensure the sensor is reading correctly as the exhaust heats up.