CLAAS Id7526h / 7526h – MFA (A100) - Armrest Multifunction Module: Voltage of the signal specified by the 2 engine speed memory too high contact.

The engine speed memory 2 function becomes inactive. The control module is receiving a voltage signal from the engine speed memory 2 switch that exceeds the expected normal operating range. This typically indicates a short-circuit to a power source or an internal failure within the switch itself.

• CLAAS Arion 640 - 510 series
• CLAAS Axion 850 / 800 series
• CLAAS Axion 950 - 920 series

1. 1

   Locate the engine speed memory 2 contact switch (S179) and the MFA (A100) armrest module

2. 2

   Inspect the connectors and continuity of the wiring harness linking the S179 switch to the MFA A100 module

3. 3

   Test the circuit specifically for short-circuits to a 12V power source

4. 4

   Check the resistance of the S179 contact switch to ensure it is operating within specification and not internally shorted

5. 5

   Verify the sources of energy (fuses, supply voltage, and ground connections) to the armrest module

1. 1

   Document Codes

   Note all error codes present on the tractor to ensure this code wasn't generated as a cascade effect from another electrical fault.

2. 2

   Access the Armrest

   Carefully disassemble the necessary trim on the MFA armrest to access the S179 switch and its wiring harness.

3. 3

   Perform Multimeter Testing

   Back-probe the S179 switch connector. If the voltage is out of range while the switch is at rest, disconnect the switch.

4. 4

   Isolate the Fault

   If the high voltage remains on the harness side with the switch unplugged, repair the short-to-power in the wiring harness between the switch and the MFA (A100) module. If the voltage returns to normal/drops when unplugged, the S179 switch is internally faulty and must be replaced.

5. 5

   Module Replacement (Worst Case)

   If the switch and wiring harness both test perfectly fine, the fault lies within the MFA (A100) armrest multifunction module itself, which will need to be replaced or reprogrammed.

6. 6

   Clear and Verify

   Clear all error codes from the system, then operate the tractor and test the engine speed memory 2 function to verify the anomaly does not return.