John Deere 871.18 – ATC: Refrigerant Pressure Extremely Low

The A/C pressure sensor has detected a pressure value that has dropped below the minimum acceptable threshold for safe compressor operation, usually pointing to a loss of refrigerant.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8225R
• 8245R
• 8270R
• 8295R
• 8320R
• 8335R
• 8345R
• 8370R
• 8400R
• 9470RT
• 9520RT
• 9570RT
• CH570
• CH670
• 3520

1. 1

   Check refrigerant levels by connecting A/C manifold gauges to the high and low side service ports to verify static system pressure.

2. 2

   Inspect for leaks along all A/C hoses, fittings, the condenser, and the compressor looking for refrigerant oil residue, or use an electronic leak detector/UV dye.

3. 3

   Verify the A/C pressure sensor (transducer) and its wiring harness for proper voltage and resistance if gauge pressure shows the system is fully charged.

1. 1

   Recover Refrigerant

   Do not vent refrigerant into the atmosphere. Use an approved A/C recovery machine to extract any remaining R134a refrigerant from the system.

2. 2

   Repair the Leak / Replace Sensor

   Fix the identified leak (replace O-rings, hoses, etc.). If the pressure sensor itself is leaking or electrically failed, unthread it from the fitting and install a new one.

3. 3

   Replace O-Rings

   When installing a new pressure sensor, always lubricate and install a new O-ring to prevent future leaks.

4. 4

   Evacuate the System

   Pull a deep vacuum on the A/C system for at least 30-45 minutes to remove moisture and air.

5. 5

   Recharge

   Recharge the system with the exact factory-specified weight of R134a refrigerant.

6. 6

   Clear Codes

   Cycle the key and use a diagnostic tool to clear the ATC 000871.18 code, then run the A/C on maximum cooling to verify operation.