John Deere 1231.12 – TEC (Tractor Electronic Control Unit) / TEI (Tractor Electronic Interface) / RLC: Vehicle CAN BUS, High Error Rate / Implement CAN Message Overflow

The controller is receiving too many messages on the CAN bus, exceeding its error limit. This condition is most commonly caused by a mixture of ISO-compliant and non-ISO-compliant devices connected to the implement connector, or a physical fault (such as a short) in the 29-bit Tractor CAN BUS wiring.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 9330
• 9430
• 9530
• 9630
• 6120-6420
• 6230
• 6330
• 6430
• 8245R-8400R
• 8310RT-8360RT
• 9470RT
• 9520RT
• 9570RT
• 6145J
• 6165J
• 6180J
• 6205J
• E300LC
• E360
• E360LC

1. 1

   Disconnect all devices and implements connected to the tractor's rear ISOBUS implement connector

2. 2

   Cycle the key switch off and back on to see if the code clears

3. 3

   Check the ISOBUS breakaway connector (IBBC) at the rear of the tractor for dirt, corrosion, moisture, or bent pins that could be shorting the CAN High and CAN Low lines

4. 4

   Using a multimeter, measure the voltage on the CAN bus lines at the implement connector. CAN High and CAN Low should both rest around 2.5V. A reading of 0V or 5V indicates a short to ground or power

1. 1

   Isolate the Fault

   Disconnect all implement CAN bus devices and cycle the key switch.

2. 2

   Identify Incompatible Devices

   If the code clears, reconnect your implements one by one. The device that triggers the code is either non-ISO compliant or has a faulty controller. Remove or replace the offending device.

3. 3

   Inspect and Clean the Receptacle

   If the code persists with nothing connected, thoroughly clean the ISOBUS implement breakaway connector using electrical contact cleaner. Replace the connector if internal pins are corroded or shorted.

4. 4

   Trace the Wiring Harness

   Inspect the 29-bit Tractor CAN BUS wiring harness running from the implement connector to the TEC/TEI control unit. Look for chafing, pinched wires, or melted insulation.

5. 5

   Repair Wiring

   Repair any damaged sections of the CAN bus wiring harness using proper splicing techniques and heat shrink.

6. 6

   Update/Replace Control Unit

   If the wiring and connectors are perfectly intact and the code remains active, the TEC or TEI control unit may have an internal fault or require a software update. Have a John Deere dealer reflash the TEC/TEI module or replace it if it has failed internally.