Deutz-Fahr I18 – Instrument Panel: Coolant temperature sensor short-circuiting to ground

The coolant temperature sensor is short-circuiting to ground (earth), meaning the electrical signal wire from the sensor is making direct contact with the tractor's chassis/ground, or the sensor has failed internally, causing the voltage signal to drop to zero.

• Agroplus 310, 320, 410, and 420 Profiline series tractors
• Deutz-Fahr Agrofarm series (85, 100, 410, 420, 430)
• Deutz-Fahr Agrotron series (80, 90, 100, 105, M600, K90, K100, K110, K120)
• Same Explorer 90

1. 1

   Inspect the wiring harness leading to the engine coolant temperature sensor for chafing, pinched wires, or melted insulation that could cause the signal wire to touch the engine block or chassis.

2. 2

   Disconnect the coolant temperature sensor and use a multimeter to check the signal wire for continuity to ground. If there is continuity while disconnected, the wiring harness is shorted.

3. 3

   Check for an internal short to ground within the sensor itself using a multimeter.

4. 4

   If no short circuit to earth is discovered in the wiring or the sensor, check the Instrument Panel (Infocenter) itself, as it may have an internal fault.

1. 1

   Cool down engine

   Turn off the tractor, remove the key from the ignition, and allow the engine to cool completely to avoid burns from hot pressurized coolant.

2. 2

   Locate sensor

   Locate the engine coolant temperature sensor on the engine block or thermostat housing.

3. 3

   Disconnect connector

   Disconnect the electrical connector from the sensor.

4. 4

   Prepare for coolant leak

   If diagnostic tests point to a faulty sensor, place a catch pan under the sensor area to catch any escaping coolant.

5. 5

   Remove sensor

   Unscrew and remove the old coolant temperature sensor.

6. 6

   Install new sensor

   Install the new OEM coolant temperature sensor and tighten it to the manufacturer's specifications.

7. 7

   Reconnect connector

   Reconnect the electrical connector.

8. 8

   Top off coolant

   Top off the engine coolant to the correct level.

9. 9

   Clear alarm codes

   Turn the starter key to the "O" (OFF) position, then back to the "I" (ON) position. Verify that the I18 code is no longer active on the display.