Fendt A.1.23 – A002 - ECU, enhanced control: Auxiliary Control Valve Overvoltage

The supply voltage to the Y016 auxiliary control valve (position 2, blue) has exceeded 18 volts. As a safety measure, the valve automatically moves into the neutral position and locks out operation to prevent uncontrolled hydraulic movements or electrical damage.

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1. 1

   Test the tractor's alternator output while running (System Voltage Check). A failed alternator voltage regulator can cause system-wide overvoltage exceeding 18V.

2. 2

   Inspect the wiring harness leading to the Y016 valve for chafing or a short-to-power.

3. 3

   Disconnect connector X327 at the Y016 valve. Check the pins for corrosion, water ingress, or bridging that could cause voltage spikes. Measure the supply voltage at the connector with the key ON.

4. 4

   If the supply voltage at the harness is a normal 12V-14V but the code persists, suspect an internal valve fault where the circuit board or solenoid has failed and is misreporting the voltage.

1. 1

2. 2

   Prepare machine

   Park the tractor on level ground, lower all hydraulic implements, and turn off the engine. Relieve all hydraulic pressure.

3. 3

4. 4

5. 5

   Access control block

   Unscrew and remove the right-hand entrance step of the cab. Pull the right auxiliary fuel/hydraulic tank outwards to gain clear access to the central control block.

6. 6

7. 7

8. 8

   Disconnect valve

   Locate the Y016 valve (the 2nd control valve on the underside of the central hydraulic control block). Note: The EPC control valve is sandwiched between Y015 [Valve 1] and Y016 [Valve 2]. Disconnect the X327 electrical connector from the Y016 valve (marked with a blue identifier).

9. 9

10. 10

11. 11

    Remove valve

    Unbolt the tie rods/anchor bolts holding the valve section in the stack. Remove the faulty Y016 valve.

12. 12

    Install new valve

    Install the new valve section, ensuring all O-rings are properly seated in their counterbores to prevent internal leakage. Torque the anchor bolts to 30 Nm.

13. 13

    Reassemble

    Reconnect the X327 connector, push the auxiliary tank back into place, and reinstall the right step.

14. 14

    Clear codes and test

    Clear the fault codes using the tractor terminal or FENDIAS diagnostic software, and test the blue auxiliary circuit for proper operation.