Tadiran Error E6 — Indoor/Outdoor Unit Communication Failure

What Does This Error Mean?

Tadiran Error E6 means the indoor and outdoor units of your air conditioner have lost communication with each other. The system cannot operate safely without this link and shuts down.

Affected Models

Tadiran Inverter Series
Tadiran Alpha
Tadiran Superior
Tadiran Elite

Common Causes

Communication cable between indoor and outdoor units is damaged, loose, or corroded
Outdoor unit PCB (control board) has failed
Indoor unit PCB has failed
Voltage supply to one of the units is interrupted
Incorrect wiring after a recent installation or service

How to Fix It

Reset the air conditioner

Turn the unit off at the wall breaker, wait 3 minutes, then restore power. If E6 clears and the unit runs normally, the error was a temporary glitch.
Check the circuit breaker

Ensure the circuit breaker for the outdoor unit has not tripped separately from the indoor unit. Both units must be powered for communication to work.
Inspect visible communication wiring

If you can safely access the outdoor unit's wiring connection, check whether the communication cable (usually a thin 2–3 wire cable alongside the power cables) is visibly damaged or disconnected.
Call a technician

E6 communication faults require testing of PCB boards and wiring with specialist tools. Do not attempt internal repairs yourself.

When to Call a Professional

Yes — E6 almost always requires an HVAC technician to inspect the communication wiring and control boards.

Tadiran Error E6 — Communication Loss

E6 means the two halves of your split system — the indoor unit and the outdoor unit — can no longer talk to each other. The indoor unit sends commands (cool to 22°C, set fan speed, etc.) through a communication wire to the outdoor unit’s compressor. Without this link, neither unit can operate safely.

Most Likely Cause

In systems more than 5 years old, corrosion or physical damage to the communication cable is the most common cause. The cable runs outdoors (often clipped to or inside the refrigerant pipe chase) and is exposed to weather year-round.

What a Technician Will Do

Test voltage at the communication terminals on both units
Check continuity of the communication cable with a multimeter
Inspect both PCBs for burn marks or failed components
Replace the faulty cable or component

Frequently Asked Questions

Why did E6 appear suddenly after years of working fine?

The communication cable runs between the indoor and outdoor units — often outdoors. UV exposure, pests, or physical damage can degrade the cable over time. Corrosion at connection terminals is another common cause, especially in humid or coastal areas.

How expensive is an E6 repair?

If it is a wiring issue, repair is relatively inexpensive (labour to trace and replace the cable). If a control board (PCB) has failed, costs are higher — typically $150–$400 for a replacement PCB including labour.