John Deere 170 – ATC: Climatrac Cab Air Temperature Sensor Voltage Too Low

The Automatic Temperature Control (ATC) unit has detected that the voltage from the cab air temperature sensor is below the normal operating range (less than 0.10 VDC). This typically indicates a short to ground in the sensor's circuit or an internal failure of the sensor itself. The ClimaTrak system relies on this sensor to measure the air temperature inside the operator's cab to automatically regulate heating and cooling output.

• 6020 to 6920S Series
• 7720
• 7820
• 7920
• 8120
• 8220
• 8320
• 8420
• 8520
• 8230T
• 8330T
• 8430T
• 9230
• 9330
• 9430
• 9530
• 9630

1. 1

   Inspect the cab recirculation air filter and the air conditioning condenser at the front of the tractor to ensure they are clean and free of debris

2. 2

   Locate the cab temperature sensor (typically behind the instructional seat) and ensure it is not covered or obstructed

3. 3

   Inspect the wiring harness and connector pins at the sensor for chafing, breaks, corrosion, or signs of a short to ground

4. 4

   Test the sensor (thermistor) with a multimeter set to Ohms. Measure resistance at room temperature, then warm it (e.g., with a hairdryer) to verify the resistance changes. If it reads open, shorted, or does not change, the sensor is faulty

1. 1

   Prepare machine

   Park the machine on a level surface, shut down the engine, and remove the key.

2. 2

   Access the sensor

   Locate the cab air temperature sensor behind the passenger or instructional seat. Remove any necessary panels or the seat itself to gain access.

3. 3

   Remove faulty sensor

   Carefully disconnect the electrical connector. Remove any clips or screws holding the sensor in place and extract the old sensor.

4. 4

   Install new sensor

   Install the new temperature sensor and securely fasten it in its original position. Reconnect the electrical connector.

5. 5

   Reassemble components

   Reinstall any panels or the seat that were removed during the access step.

6. 6

   Verify repair

   Start the tractor and operate the ClimaTrak system. Clear the diagnostic trouble codes using the tractor's display or service tool if necessary, and verify the fault code does not return. If it returns, further diagnosis of the wiring harness and ATC unit is required.