Fendt A.1.74 – A057 - ECU, steering controller (Auto-Guide): S088 - Switch, Autoguide pressure

The system has detected a break in the pressure switch signal line or a short-circuit in the supply line of the pressure switch signal line.

• 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
• Fendt 400 Vario COM III
• Fendt 700 Vario COM III
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• Fendt 820 Vario greentec COM III
• Fendt 900 Vario COM III

1. 1

   Visually inspect the wiring harness leading to the S088 Autoguide pressure switch for physical damage, chafing, or disconnected plugs.

2. 2

   Perform a continuity test on the signal line between the S088 switch connector and the steering controller ECU to check for an open circuit.

3. 3

   Test the signal and voltage supply lines for a short to ground or a short to power.

4. 4

   Test the S088 pressure switch to ensure it opens and closes correctly when hydraulic steering pressure is applied.

1. 1

   Power Down

   Turn off the tractor ignition and engage the parking brake.

2. 2

   Locate the Switch

   Locate the S088 Auto-Guide pressure switch, which is typically mounted on or near the Auto-Guide steering valve block (Y087).

3. 3

   Repair Wiring

   If your diagnostic checks revealed a broken wire or short circuit in the harness, repair the damaged section of the wiring harness and secure it with loom tape/zip ties.

4. 4

   Replace the Switch

   If the wiring tests fine but the switch has failed internally: Disconnect the electrical connector from the S088 switch, clean the area around the switch, unscrew the faulty pressure switch, install the new OEM pressure switch and tighten to the manufacturer's specified torque, and reconnect the electrical harness.

5. 5

   Clear Codes and Test

   Turn the ignition on. Use the Fendt terminal to navigate to the fault code menu and clear the stored A.1.74 code. Test the Auto-Guide system in the field to ensure it engages properly and disengages when the steering wheel is manually turned.