What It Means
Communication loss between CCM controller and NIM interface module.
York All Systems
York Error Code 01#
Troubleshooting guide for the York system fault 01#.
Possible Causes
- Damaged, loose, or reverse-polarity CCM-to-NIM wiring.
- Loss of power to NIM interface module.
- NIM address or DIP-switch configuration mismatch.
- Faulty NIM interface module requiring replacement.
Not sure which one it is — or if it's none of these? Try ACLogics today.
Disclaimer: This information is for general reference. Error codes can vary by model and production year. Always refer to your machine's specific manual and the information printed on the unit itself.
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Full Diagnosis
01# reports a loss of communication between the CCM (Communicating Control Module) and the NIM (Network Interface Module) — the board that typically bridges the system to a building management network or remote monitoring interface. This is distinct from 00# (CCM-to-main PCB), 02# (CCM-to-Function Module), and 03# (CCM-to-gateway/PC) faults, each of which points to a different device on the communication bus. Because the NIM link is generally used for monitoring/BMS integration rather than core operation, this fault often does not stop compressor or fan operation but does disable remote visibility and control until communication is restored.
All Recorded Causes
Check the communication cable and connectors between the CCM and the NIM for damage, looseness, or incorrect polarity. Confirm the NIM has power and its status LED (if equipped) indicates normal operation. Verify address/DIP-switch settings on the NIM match the system configuration. Reseat or replace the NIM if wiring tests good but the fault persists.
Verify Before Replacing Parts
- Confirm the exact York model family and default context before acting on a generic code description.
- Confirm board LEDs, wiring polarity, and model compatibility before replacing control boards — this York fault points at check the communication cable and connectors between the CCM and the NIM for damage, loose….
- Check for intermittent communication faults caused by connectors, moisture, or damaged harnesses, and rule out confirm the NIM has power and its status LED (if equipped) indicates normal operation.
- After the correction, run the system long enough to confirm the default fault does not return under normal load.
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