Fendt 1E.1.21 – Engine Control Unit (ECU): K063 - Heater flange relay

The system has detected a break in the wiring (open circuit) or a short circuit in the K063 relay circuit. The engine pre-heater is inoperable, which can cause hard starting or rough running in cold weather conditions.

• 309 Vario COM III
• 310 Vario COM III
• 311 Vario COM III
• 312 Vario COM III
• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• 300 Vario series
• 307
• 308
• 309
• 310
• 311
• 312
• 400 Vario series
• 411
• 412
• 413
• 414
• 415
• 700 Vario series
• 711
• 712
• 714
• 716
• 718
• 800 Vario series
• 815
• 818
• 819
• 820
• 822
• 824
• 826
• 828
• 900 Vario series
• 922
• 924
• 927
• 930
• 933
• 936
• 939

1. 1

   Locate the K063 relay on the left side of the engine, mounted on or near the intake pipe

2. 2

   Visually inspect the wiring harness and connector at the K063 relay for obvious wire breaks, chafing, or corrosion

3. 3

   Test voltage at terminal 86 (inductive input) on the relay: it should read 0 VDC when inactive, and 12 VDC from the ECU when active (ambient temperature below 5°C)

4. 4

   If 12 VDC is not present when commanded, check wiring between the ECU and the relay; if voltage is present but the relay does not close, the relay is faulty

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the tractor's battery via the battery disconnect relay (K064) to prevent accidental shorts while working on the high-amperage pre-heater circuit.

2. 2

   Access the Relay

   Navigate to the left side of the engine block and locate the K063 relay on the intake pipe.

3. 3

   Repair Wiring (If Applicable)

   If your diagnostic checks revealed a broken wire or short to ground in the harness, repair the damaged section of the wire and secure it with heat shrink and loom.

4. 4

   Replace the Relay

   If the wiring is intact, unplug the electrical connector and unbolt the faulty K063 relay. Mount the new OEM relay and securely reconnect the harness.

5. 5

   Reassemble and Clear Codes

   Reconnect the battery. Connect the SERDIA / FENDIAS diagnostic tool to the tractor and clear the stored fault code (often associated with internal SERDIA codes FC:0011 or FC:0021).

6. 6

   Verify Operation

   Turn the ignition on in cold conditions (under 5°C) to verify that the pre-heater dash light illuminates and the relay clicks on.