Fendt 1.2.04 – Engine Control Unit (ECU): B089 - Temperature sensor, Deutz

The coolant temperature sensor has a break in the wiring or a short circuit, or the engine coolant temperature is reading outside of the designated setpoint area.

• 411 Vario COM III
• 412 Vario COM III
• 413 Vario COM III
• 414 Vario COM III
• 415 Vario COM III
• 712 Vario COM III
• 714 Vario COM III
• 716 Vario COM III
• 718 Vario COM III
• 818 Vario COM III
• 820 Vario COM III
• 200 Vario Series
• 300 Vario Series (e.g., 309, 310, 311, 312, 313)
• 400 Vario Series (e.g., 411, 412, 413, 414, 415)
• 500 Vario Series (e.g., 511, 512, 513, 514, 516)
• 700 Vario Series (e.g., 711, 712, 714, 716, 718, 720, 722, 724)
• 800 Vario Series (e.g., 815, 817, 818, 819, 820, 822, 824, 826, 828)
• 900 Vario Series (e.g., 912, 913, 922, 924, 927, 930, 933, 936)

1. 1

   Inspect the wiring harness and the sensor's sealed electrical connector for a cable break, corrosion, or short circuit (refer to Wiring diagram Sheet 36).

2. 2

   Verify if the coolant temperature is genuinely outside the setpoint area by checking for actual engine overheating or a faulty thermostat.

3. 3

   Note that after correcting the physical error, the fault codes (specifically FC:0037, 0038) must be deleted from the engine control unit using SERDIA.

1. 1

   Cool engine

   Allow the engine to cool completely to avoid burns and to ensure the cooling system is depressurized.

2. 2

   Locate sensor

   Locate the coolant temperature sensor (B089) on the Deutz engine block.

3. 3

   Disconnect connector

   Disconnect the electrical connector from the sensor.

4. 4

   Remove sensor

   Thread out the old sensor from the engine block.

5. 5

   Apply sealant

   Apply a dab of thread sealant to the threads of the new sensor.

6. 6

   Install sensor

   Install the new sensor. Do not overtighten, as the sensor threads into aluminum.

7. 7

   Reconnect connector

   Reconnect the electrical connector, ensuring it clicks into place to seal against moisture and vibration.

8. 8

   Verify repair

   Start the engine and verify that there are no coolant leaks.

9. 9

   Clear fault codes

   Connect the SERDIA diagnostic tool to clear the stored fault codes from the engine ECU.