CLAAS Id788Fh / 788Fh – EXT (A62) - External function module: CAN bus communication timeout

The EXT external function module has not received the rear lifting, theoretical speed, and rear PTO information for more than 5 seconds via the CAN BUS. As a result, no information is available over the 7-pin ISO connector.

• Axion 800
• Axion 810
• Axion 850
• Axion 920
• Axion 950
• Axion 960
• Arion 410
• Arion 430
• Arion 510
• Arion 640

1. 1

   Perform a functional override check by activating the rear PTO and rear linkage to verify if the code is active or a passive ghost code

2. 2

   Inspect the 7-pin ISO connector for bent pins, corrosion, or lack of signal

3. 3

   Check the CLAAS vehicle CAN bus network wiring for damage

4. 4

   Inspect the bus CAN network communication module BDG (A103)

5. 5

   Inspect the lifting module REH (A58)

6. 6

   Inspect the external function module EXT (A62)

1. 1

   Verify Symptoms

   Start the tractor and attempt to operate the rear PTO and rear linkage. If they work, clear the passive code and release the machine.

2. 2

   Inspect the 7-Pin ISO Connector

   Check the implement connector at the rear of the tractor. Clean the contacts and verify the wiring harness directly behind the plug for chafing or breaks.

3. 3

   Test CAN Bus Integrity

   Using a multimeter or oscilloscope, probe the CAN-High and CAN-Low lines on the CLAAS vehicle CAN bus network to ensure proper voltage (typically ~2.5V to 2.7V) and check for short-circuits to ground or 12V.

4. 4

   Check Module Connections

   Inspect the wiring harness connectors at the EXT (A62), BDG (A103), and REH (A58) modules. Ensure they are seated securely and free of moisture.

5. 5

   Module Replacement

   If the wiring and CAN bus network are intact but the EXT module still fails to receive/transmit data to the 7-pin ISO connector, the EXT (A62) module or the BDG (A103) gateway module may have suffered an internal failure and will require replacement and reprogramming via the CLAAS Diagnostic System.