CLAAS Id75D9h / 75D9h (326) – TR1 (A57-1): The comparison of the information from the reverser output speed sensor and the theoretical speed sensor is inconsistent.

The transmission control system is detecting a mismatch between the rotational speed measured at the reverser output and the calculated (theoretical) ground/axle speed. This inconsistency typically points to a faulty sensor, a wiring harness issue, or an incorrect sensor adjustment.

• Axion 800 Series
• Axion 810
• Axion 850
• Arion 600 Series
• Arion 610
• Arion 630
• Arion 640
• Arion 500 Series
• Arion 400 Series
• Arion 410
• Arion 430
• Ares Series

1. 1

   Check the connectors at sensors B227 and B229 for corrosion or moisture, and verify wiring harness continuity to the TR1 module.

2. 2

   Check for potential short-circuits to ground, short-circuits to 12V, or open circuits in the sensor wiring.

3. 3

   Measure the resistance and frequency of both sensors to see if they fall within OEM specifications.

4. 4

   Verify the physical adjustment (air gap/depth) of the sensors in their mountings.

5. 5

   Verify that the TR1 module is supplying the correct reference voltage (typically 10V) to the sensors.

1. 1

   Prepare machine

   Safely park the tractor, turn off the engine, and engage the parking brake.

2. 2

   Locate components

   Locate the TR1 (A57-1) transmission module and the two speed sensors: B227 (rear axle crown) and B229 (Revershift output).

3. 3

   Clean connectors

   Disconnect the wiring harness at both sensors. Clean the contacts with electrical contact cleaner if dirt or moisture is present.

4. 4

   Test wiring continuity

   Using a multimeter, test the wiring continuity from the sensor connectors back to the corresponding pins on the TR1 module. Repair or replace any damaged wiring sections.

5. 5

   Test sensor resistance

   Test the resistance of sensors B227 and B229. If either sensor reads out of specification or shows an internal open/short, it must be replaced.

6. 6

   Adjust sensor clearance

   If the sensors test fine electrically, check their mounting depth and adjust the clearance according to the specific model's service manual.

7. 7

   Reinstall and reconnect

   Install the new or adjusted sensor(s) and reconnect the wiring harnesses.

8. 8

   Connect diagnostic system

   Connect the CLAAS Diagnostic System (Metadiag / CDS) to the tractor.

9. 9

   Perform system reset

   Perform an "ISC" (Interactive System Control) reset, which is requested by the system for this specific fault code, and clear the inactive codes from the TR1 memory.

10. 10

    Test drive

    Test drive the tractor through its ranges to ensure the transmission shifts correctly and the fault code does not return.