Massey Ferguson 10.02.25 – AC Module (AIRCON): No Vehicle Speed Information Received On The CAN BUS To AC Module (AIRCON)

This indicates a communication failure on the tractor's Controller Area Network (CAN bus). Specifically, the Air Conditioning control module is failing to receive the required vehicle speed data broadcasted by the transmission or engine control modules. The AC system uses this speed data to regulate compressor load, condenser fan speeds, and cabin climate control efficiency.

• 7724S
• 5712SL
• 7722
• 7722S
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7726S
• 5711SL
• 7718S
• 7719
• 7714
• 7716S
• 7720
• Tier 4 (2015-2021)
• 7715S
• 7724
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 8600 Series
• 8700 Series

1. 1

   Verify Dashboard Speedometer: Drive the tractor and check if the instrument cluster displays the correct vehicle speed. If the speedometer is dead, the root cause is likely a faulty vehicle speed sensor or transmission controller, not the AC module.

2. 2

   Check for Accompanying Codes: Scan the tractor for other CAN bus or transmission codes (e.g., Engine speed error / CAN message not valid). If multiple modules are reporting missing speed data, the CAN bus network or the speed sensor itself is at fault.

3. 3

   Inspect Wiring and Connectors: Check the wiring harness leading to the AC Module. Look for chafed wires, rodent damage, or loose/corroded pins at the connector block.

4. 4

   Test CAN Bus Resistance: Using a multimeter, check the resistance across the CAN High and CAN Low pins at the AC module connector (with the battery disconnected). It should read approximately 60 ohms.

1. 1

   Disconnect Power

   Turn off the tractor and disconnect the negative battery terminal to prevent electrical shorts.

2. 2

   Clean Connections

   Disconnect the main harness from the AC Module. Spray the pins with a high-quality electrical contact cleaner. Reconnect and ensure the locking tab is fully seated.

3. 3

   Repair CAN Wiring

   If physical damage is found on the CAN bus twisted-pair wires leading to the AC module, cut out the damaged section and solder/heat-shrink new wiring to restore network integrity.

4. 4

   Replace Speed Sensor (If Applicable)

   If diagnostic checks proved the vehicle speed sensor is dead (no speed on dash), locate the inductive speed sensor on the transmission housing. Disconnect its pigtail, unthread the old sensor, install the new sensor, and reconnect.

5. 5

   Clear Codes and Test

   Reconnect the battery, start the tractor, and clear the fault codes using an AGCO EDT (Electronic Diagnostic Tool) or equivalent scanner. Drive the tractor to verify the AC module receives the speed signal and the code does not return.

6. 6

   Replace AC Module (Last Resort)

   If the CAN bus wiring is perfectly intact, the speed sensor works, and the code persists, the CAN transceiver inside the AC Module has likely failed. The module must be replaced and reprogrammed by a dealer.