CLAAS Id7520h / 7520h – MFA (A100) armrest multifunction module: Voltage of the signal specified by the transmission neutral contact too high

The system is receiving a voltage reading from the neutral safety circuit that exceeds the expected normal operating range. Because of this out-of-bounds high voltage, the system registers the transmission neutral contact as inactive.

• CLAAS AXION series
• AXION 850
• AXION 920
• AXION 950
• CLAAS ARION series
• ARION 640

1. 1

   The transmission neutral contact sensor (designated as component S180)

2. 2

   The MFA (A100) armrest multifunction module

3. 3

   Inspect the wiring harness running between the S180 transmission neutral contact and the A100 MFA module for chafed wires shorting to a 12V power source

4. 4

   Disconnect the S180 sensor and test it with a multimeter for internal shorts

5. 5

   Check the connector pins at the MFA (A100) module for corrosion or damage

1. 1

   Locate the Sensor

   Locate the transmission neutral contact sensor (S180) on the transmission housing.

2. 2

   Inspect Wiring

   Thoroughly trace the wiring from the S180 sensor back to the MFA (A100) armrest module. Repair any damaged wires or connectors that are causing a short to power.

3. 3

   Test/Replace Sensor

   If the wiring is intact and the reference voltage from the module is correct, the S180 sensor has likely failed internally. Remove the faulty sensor and install the replacement.

4. 4

   Module Verification

   If both the sensor and the wiring harness test perfectly, the fault may lie within the MFA (A100) armrest multifunction module itself, which may require dealer-level testing or replacement.

5. 5

   Clear Codes

   After replacing the sensor or repairing the wiring, clear the fault codes and cycle the transmission to ensure the neutral contact is now registering as active.