Massey Ferguson 10.01.26 – AC Module (AIRCON): No Engine Coolant Temperature Information Received On The CAN BUS To AC Module (AIRCON)

The Air Conditioning (AC) control module is failing to receive the engine coolant temperature data packet over the tractor's CAN BUS network. The Engine Control Unit (ECU) normally reads the physical Engine Coolant Temperature (ECT) sensor and broadcasts this value onto the CAN BUS for other modules (like the AC module and the Dash) to utilize. When this signal is missing, the AC system may disable the compressor to prevent potential engine overheating or fail to regulate automatic climate control properly.

• 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

1. 1

   Scan for Engine ECU Codes: Use the AGCO Electronic Diagnostic Tool (EDT) to check if the Engine ECU has logged any faults for the physical Coolant Temperature Sensor. If the ECU is also reporting a coolant sensor fault, the issue is with the sensor or its direct wiring, not the CAN BUS.

2. 2

   Live Data Verification: Check the live data in the Engine ECU to see if it is reading the coolant temperature accurately. If the ECU reads the temperature fine but the AC module does not, the issue lies in the CAN BUS communication lines between the two modules.

3. 3

   Inspect the ECT Sensor and Connector: Locate the Engine Coolant Temperature sensor on the engine block/thermostat housing. Disconnect the pigtail and inspect the pins for corrosion, moisture, or backed-out terminals.

4. 4

   CAN BUS Network Test: Check the CAN High and CAN Low wiring harness connections at the AC module for continuity, shorts to ground, or physical damage.

1. 1

   Disconnect Battery

   Always disconnect the negative battery terminal before working on the tractor's electrical or CAN BUS systems.

2. 2

   Sensor Replacement (If ECU is not reading temperature)

   Drain a small amount of engine coolant to bring the fluid level below the sensor port. Disconnect the electrical connector from the ECT sensor. Use a deep socket (typically 22mm depending on the exact sensor) to unscrew the old sensor from the engine block. Clean the threaded mounting area. Apply appropriate thread sealant to the new sensor (if not pre-applied) and thread it into place. Reconnect the electrical pigtail. Refill the coolant to the proper level.

3. 3

   Wiring Repair (If CAN BUS or pigtail is faulty)

   If the diagnostic checks revealed a broken CAN wire between the ECU and the AC module, locate the break using a multimeter and repair the wire using weather-sealed splice connectors. If the sensor pigtail is damaged, splice in a new 2-wire ECT connector pigtail.

4. 4

   Clear Codes

   Reconnect the battery, turn the key to the ON position, and use the AGCO diagnostic tool to clear the 10.01.26 fault code from the AC module. Run the tractor and verify the AC system engages.