CLAAS Id788Ah / 788Ah – EXT (A62): EXT external function module has not received actual speed information

The EXT external function module has not received actual speed information for more than 5 seconds via the vehicle's CAN BUS network. Specifically, the system detects that the actual speed information is not available on the 7-pin ISO connector.

• Axion 800
• Axion 810
• Axion 850
• Axion 920
• Axion 950
• Arion 410
• Arion 430
• Arion 510
• Arion 530
• Arion 550
• Arion 620
• Arion 640
• Arion 650

1. 1

   Check the 7-pin ISO connector: Verify that the actual speed information is present at the connector and that the plug is not damaged, corroded, or disconnected.

2. 2

   Check the CLAAS vehicle CAN bus network: Inspect the wiring harness for short-circuits (to 12V or ground) or open circuits.

3. 3

   Check the BDG (A103) module: This is the CAN network communication module responsible for relaying information across the bus.

4. 4

   Check the DBD (A101) module: This is the instrument panel/dashboard module, which often processes and transmits speed data.

5. 5

   Check the EXT (A62) module: Ensure the external function module is receiving power and ground.

1. 1

   Visual & Physical Inspection

   Inspect the 7-pin ISO connector at the rear of the tractor. Clean the contacts and ensure the implement/radar speed signal wiring is intact.

2. 2

   Wiring Continuity Test

   Using a multimeter, check the resistance and continuity of the CAN bus lines between the EXT (A62), BDG (A103), and DBD (A101) modules.

3. 3

   Power & Ground Check

   Check the sources of energy (fuses, supply voltage, and ground connections) for the EXT, BDG, and DBD modules.

4. 4

   Software/Calibration Check

   Connect the CLAAS Diagnostic System (CDS) to verify the compatibility of program versions and settings between the dashboard (DBD) and the external function module (EXT).

5. 5

   Component Replacement

   If the wiring, fuses, and software are all verified to be in working order, replace the faulty component (starting with the 7-pin connector/wiring, followed by the EXT or BDG module if CAN communication is internally failing).