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Error code reference

Mitsubishi Air Conditioner Error Code E.SAF

Safety circuit fault

Mitsubishi codesMitsubishi air conditioner codes

Safety circuit fault - safety circuit fault occurred or shorting wire between S1/PC or S2/PC disconnected.

First step from the service manual

Check safety relay module connections or shorting wires between S1-PC and S2-PC.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What E.SAF means on a Mitsubishi air conditioner

The E.SAF error code on a Mitsubishi air conditioner indicates a fault within the safety circuit, which is a dedicated protective loop designed to shut down the system when unsafe operating conditions are detected. This circuit typically incorporates external safety devices such as pressure switches, flow switches, or thermal protectors, wired in series between terminals S1, S2, and PC on the control board. When the circuit is broken or a fault is detected, the system halts operation and displays E.SAF to prevent equipment damage or hazardous conditions.

One of the most common triggers for this code is a disconnected or missing shorting wire between the S1-PC or S2-PC terminals. In installations where no external safety devices are connected, these terminals require a shorting jumper wire to complete the circuit. If that wire is absent, loose, or broken, the control board reads the open circuit as a safety fault. Similarly, if external devices such as a refrigerant pressure switch or condensate overflow sensor are wired into the safety loop and one of them opens due to an actual fault condition, E.SAF will appear.

Diagnosing this error should begin with a physical inspection of the S1, S2, and PC terminal connections at the indoor unit control board. Verify that shorting wires or external device wiring are firmly seated and undamaged. If external safety devices are present in the loop, test each one individually for continuity to determine whether the fault is a wiring issue or an actual triggered safety device. A failed safety relay module can also produce this code if the relay itself is faulty rather than the wiring.

Source: manufacturer service documentation.

Common causes of E.SAF

  1. 01

    Missing or disconnected shorting wire between S1-PC or S2-PC terminals

    Wiring / connection

    When no external safety devices are installed, a shorting jumper wire must bridge the S1-PC and S2-PC terminals to complete the safety circuit. If this wire is absent or has come loose, the board immediately registers a safety fault.

  2. 02

    Triggered external safety device in the safety loop

    Wiring / connection

    Pressure switches, flow switches, or condensate overflow sensors wired into the S1/S2/PC loop will open the circuit when they detect an out-of-range condition. Each device should be tested individually for continuity to identify which one has tripped.

  3. 03

    Damaged or broken safety circuit wiring

    Wiring / connection

    Wiring between the S1, S2, and PC terminals can become pinched, corroded, or broken over time, especially during service or installation work. A visual inspection and continuity test of all wiring in the loop will identify breaks.

  4. 04

    Faulty safety relay module

    Part replacement

    The safety relay module itself can fail internally, causing the control board to read an open safety circuit even when all wiring and external devices are intact. Replacing the relay module is required if all other wiring checks out correctly.

  5. 05

    Loose terminal connections at the control board

    Wiring / connection

    Vibration during operation or improper installation can cause the wiring connectors at the S1, S2, or PC terminals to loosen over time. Reseating and securing all terminal connections at the board is a quick step that can resolve intermittent E.SAF faults.

See the test procedure for each cause

Frequently asked questions about E.SAF

What does E.SAF mean on a Mitsubishi air conditioner?
E.SAF indicates a fault in the safety circuit of the Mitsubishi air conditioner. This circuit is a protective loop involving terminals S1, S2, and PC on the control board, and it monitors connected safety devices or requires shorting wires to complete the circuit. When the circuit is open or a connected safety device trips, the unit shuts down and displays E.SAF. The fault can be caused by missing jumper wires, a triggered safety device, damaged wiring, or a failed safety relay module.
How do I fix an E.SAF error on a Mitsubishi air conditioner?
Start by inspecting the S1, S2, and PC terminals on the indoor unit control board to confirm that shorting wires or external device wiring are securely connected. If shorting wires are present, check them for continuity. If external safety devices such as pressure switches are wired into the loop, test each one individually to find any that have opened. If all wiring and devices check out, the safety relay module itself may need replacement.
Is it safe to keep running my air conditioner when E.SAF is displayed?
No, the unit will not continue to run when E.SAF is active because the safety circuit has forced a shutdown. Attempting to bypass the safety circuit to restore operation is not recommended, as the circuit is designed to protect against potentially hazardous conditions. The underlying cause should be diagnosed and corrected before resuming normal operation.
Will resetting the unit clear the E.SAF error?
A simple power reset may temporarily clear the error display, but E.SAF will return if the underlying fault in the safety circuit is not corrected. If a safety device such as a pressure switch has tripped due to a real system condition, that condition must be resolved first. Persistent E.SAF errors after repeated resets indicate a wiring fault or component failure that requires hands-on inspection.
How much does it cost to repair an E.SAF error on a Mitsubishi air conditioner?
Repair costs depend on the root cause. If the fault is simply a loose or missing shorting wire, a technician visit to reseat or replace the wire would typically cost in the range of $75 to $150 for labor. If an external safety device has failed and needs replacement, parts and labor could range from $100 to $300 depending on the component. A failed safety relay module replacement, including parts and labor, generally falls in the range of $150 to $400.

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