High/Low Analog Input (AN0-AN9) — Sensor Circuit Fault
The SULLAIR-ANALOG-INPUT-FAULT (Sullair WS Controller) diesel fault code means: High/Low Analog Input (AN0-AN9) — Sensor Circuit Fault. This is a serious severity code.
- DIY difficulty
- moderate
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Common Symptoms
- WS display shows High analog input or Low analog input with a channel AN0 through AN9
Probable Causes (Ranked by Likelihood)
- Sensor failure (pressure transducer, temperature probe, etc.) High
- Wiring failure to that sensor High
Frequently Asked Questions
Which sensor is on my channel?
Channel assignment varies with machine configuration — the controller's Compressor Status view names the measurements in use. An analog-input fault is an electrical/circuit finding: check wiring, then the sensor, before believing the value it produced.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
The WS Controller is fitted to Sullair STATIONARY electric shop compressors. Portable towable Sullair units (185-class and similar) use different engine-driven controls and a different fault system — this page does not apply to them.
Check the wiring to the sensor on the reported channel first.
Then check the sensor itself — an out-of-range electrical reading means the controller lost a plausible signal, not that the measured value is real.
Per the factory manual: after resolving a fault condition, press the STOP pad to clear the FAULTED state. If the problem persists after the recommended checks, consult your Sullair distributor or factory service.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- Sullair WS Controller User Interface Manual, P/N 02250165-411 (Table 5-1 Troubleshooting Guide)distributor-hosted copy of the official Sullair manualdistributor-hosted copy of an official Sullair factory manual
Commonly Affected Vehicles
- Sullair STATIONARY electric rotary-screw compressors with the WS Controller (including VSD packages)
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