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Error code reference

Mitsubishi Air Conditioner Error Code SA

Safety stop

Mitsubishi codesMitsubishi air conditioner codes

Safety stop - safety stop function activated (during output shutoff).

First step from the service manual

Check if emergency stop device is activated or if wire between S1/PC or S2/PC is open.

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

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What SA means on a Mitsubishi air conditioner

The SA error code on a Mitsubishi air conditioner indicates that the safety stop function has been activated, resulting in a complete output shutoff of the unit. This is a protective control state, not a component failure code in the traditional sense. The system has detected a condition that triggered an external or internal safety interlock, causing the unit to halt operation and suspend all outputs until the triggering condition is resolved and the system is reset.

The safety stop function is typically tied to an emergency stop device wired into the control circuit, or to the signal wiring between terminals S1/PC or S2/PC. These terminals handle communication and control signaling between components of the system. If the wire between S1/PC or S2/PC becomes open, or if an externally connected emergency stop device is in the activated position, the controller interprets this as a commanded safety halt and shuts down output accordingly.

Common root causes include an emergency stop button or switch that has been pressed or tripped, a broken or disconnected wire in the S1/PC or S2/PC signal circuit, a loose terminal connection at the control board or wiring harness, or a faulty emergency stop device that is generating a false activation signal. Because this code involves a deliberate safety shutoff mechanism, the system will not resume normal operation until the wiring continuity is restored and the emergency stop device is confirmed to be in the deactivated position.

Source: manufacturer service documentation.

Common causes of SA

  1. 01

    Emergency stop device activated

    Wiring / connection

    An externally connected emergency stop button or switch may have been pressed or tripped into the activated position. Inspect any emergency stop devices wired into the system and confirm they are in the deactivated or reset position.

  2. 02

    Open wire in S1/PC or S2/PC circuit

    Wiring / connection

    A break or disconnection in the signal wiring between the S1/PC or S2/PC terminals will trigger the safety stop. Use a multimeter to check continuity across these wiring runs to identify any open circuit.

  3. 03

    Loose or corroded terminal connection

    Wiring / connection

    A loose screw terminal or corroded connector at the control board or wiring harness in the S1/PC or S2/PC circuit can cause an intermittent or permanent open circuit. Visually inspect and reseat all connections at the relevant terminals.

  4. 04

    Damaged control wiring

    Part replacement

    Physical damage to the signal wires, such as cuts, pinches, or rodent damage along the wiring run, can create an open circuit condition. Trace the full length of the wiring between the relevant terminals to locate any damage.

  5. 05

    Faulty emergency stop device

    Part replacement

    An emergency stop switch or relay that has failed internally may signal a stop condition even when it appears to be in the normal operating position. If wiring continuity checks out and the device cannot be reset, the device itself may need to be replaced.

See the test procedure for each cause

Frequently asked questions about SA

What does SA mean on a Mitsubishi air_conditioner?
The SA code means the safety stop function has been activated, causing the unit to shut off all outputs. This is a deliberate protective shutoff triggered by either an emergency stop device being activated or an open circuit in the S1/PC or S2/PC control wiring. The unit will not operate again until the triggering condition is corrected.
Can I fix the SA error code myself?
Some causes of the SA code are straightforward to address, such as resetting a tripped emergency stop button or reseating a loose wiring connection at the S1/PC or S2/PC terminals. However, if the issue involves tracing and repairing damaged wiring or diagnosing a faulty emergency stop device, it is recommended to have a qualified HVAC technician handle the repair to ensure the system is safe to operate.
Is the SA error code dangerous?
The SA code itself indicates the system has shut down safely in response to a detected control circuit issue. The unit is not operating, so there is no immediate danger from the system running. However, you should not attempt to bypass the safety stop circuitry, as it exists to protect both the equipment and occupants.
Will resetting the unit clear the SA error code?
Simply resetting or power-cycling the unit will not permanently clear the SA code if the underlying cause is still present. If an emergency stop device remains activated or the S1/PC or S2/PC wiring circuit is still open, the safety stop will activate again after the reset. The root cause must be identified and corrected first before a reset will hold.
How much does it cost to repair a Mitsubishi air conditioner showing the SA code?
Repair costs depend on what caused the safety stop to activate. If the fix involves resetting an emergency stop device or reseating a loose wire, costs may be limited to a service call fee, typically in the range of $75 to $150. If wiring replacement or a new emergency stop component is needed, total costs including parts and labor could range from $150 to $400 or more depending on system complexity and local labor rates.

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