John Deere 1548 – ATC: CLIMATRAK Outlet Air Temperature Sensor Voltage Too Low

The CLIMATRAK controller has detected an abnormally low voltage signal (less than 0.1 VDC) from the Outlet Air Temperature Sensor. This indicates the sensor's electrical resistance has dropped below 50 ohms, which the system interprets as an impossibly high temperature of approximately 293°F (145°C). This condition typically points to a short to ground in the sensor's electrical circuit and restricts the automatic temperature control system's ability to regulate cab temperature.

• 6020
• 6920S
• 6920SE
• 7720
• 7820
• 7920
• 8230T
• 8330T
• 8430T
• 9230
• 9330
• 9430
• 9530
• 9630
• 9420R
• 9470RT
• 9520RT
• 9570RT
• 9450
• 9540
• 9550
• 9560
• 9580
• 9640
• 9650
• 9660
• 9680 WTS
• 9860 STS

1. 1

   Check the cleanliness of the condenser at the front of the machine and ensure the cab recirculation air filter is not plugged

2. 2

   Inspect the wiring harness connected to the Outlet Air Temperature Sensor for signs of physical damage, chafing, melting, sharp bends, or breaks in insulation

3. 3

   Check the sensor's electrical connector to ensure it is clean, dry, and securely fastened

4. 4

   Use a multimeter to test the sensor's circuit for a short to ground

1. 1

   Safety First

   Park the machine on a level surface, shut down the engine, remove the key, and disconnect the battery ground cable.

2. 2

   Locate the Sensor

   Locate the Outlet Air Temperature Sensor (often designated as B223) within the HVAC module, typically in the air ducts to measure the temperature of the air being discharged into the cab. Consult the specific technical manual for its exact position.

3. 3

   Access the Sensor

   Gain access by removing panels within the cab, such as side consoles or panels around the operator's seat.

4. 4

   Remove the Old Sensor

   Carefully disconnect the electrical connector from the sensor, then unclip or unscrew the sensor from its mounting position in the air duct.

5. 5

   Install the New Sensor

   Secure the new Outlet Air Temperature Sensor in place and firmly reconnect the electrical connector.

6. 6

   Reassemble and Test

   Reinstall any panels that were removed. Reconnect the battery, start the machine, and operate the CLIMATRAK system. Verify the fault code has cleared from the diagnostic display (manually clear via the diagnostic menu if necessary).