Deutz-Fahr I19 – Instrument Panel: Temperature sensor power supply short circuit

The coolant temperature sensor is shorting to a positive feed (short circuit to battery), meaning the control module is receiving a voltage reading from the sensor circuit that is higher than the expected operating range.

• Agroplus 310, 320, 410, and 420 Profiline series tractors
• Deutz-Fahr Agrofarm (85, 100)
• 5-Series (5090 C, 5100 C, 5110 C, 5120 C)
• Virtus J series
• Same Explorer 90
• 5650 H
• 5660 HTS
• 5670 H
• 5680 H
• 5690 HTS

1. 1

   Visually inspect contacts on connector '3K' (at the instrument panel) and connector 'X5' (at the coolant temperature sensor) to ensure they are not oxidized, damaged, or loose.

2. 2

   Perform electrical testing by turning the starter key to position 'I' (ON), disconnecting connector '3K' from the instrument panel, and connecting a multimeter to pin 2 of connector 'X5' to test the circuit for an inappropriate positive feed (short to battery).

1. 1

   Safety First

   Turn off the engine, remove the ignition key, and disconnect the battery (negative terminal) before working on the engine or electrical system.

2. 2

   Trace the Harness

   If the diagnostic test confirms a short to battery voltage, trace the wiring harness between the temperature sensor (connector X5) and the instrument panel (connector 3K). Look for chafed insulation, melted wires, or pinched harnesses where the sensor signal wire may be touching a 12V power supply wire.

3. 3

   Repair Wiring

   If a short is found in the harness, repair the damaged section of wiring using appropriate weatherproof connectors and heat shrink, or replace the affected harness section.

4. 4

   Replace Sensor

   If the wiring tests perfectly fine and no external short is found, the internal circuitry of the coolant temperature sensor has likely failed. Unscrew the old sensor from the engine block/cooling system and install the replacement.

5. 5

   Reassembly & Verification

   Reconnect the sensor and instrument panel connectors. Reconnect the battery negative terminal. Turn the ignition to the ON position and verify that the I19 code has cleared from the instrument panel display.