Absolute Repairs
Absolute Repairs
Your Alliance aircon has stopped and the display shows E1. Here's what the code means, what you can safely try, and how we fixed one in Kempton Park.
Updated
Quick answer: On an Alliance split aircon, E1 can have more than one cause. It's most often linked to a communication fault between the indoor and outdoor units, but it can also point to a faulty main control board (PCB), a faulty temperature sensor, or wiring and power supply problems. On our most recent Alliance E1 job, in Kempton Park, the cause was a damaged communication cable. Because the same code can mean different faults, an assessment by a technician is highly advised before you buy any parts. You can safely try switching the aircon off at the breaker for five minutes first.
E1 tells you the aircon has detected a fault and stopped running, but it doesn't always tell you which part has failed. The most common reason is communication: the indoor unit (on the wall inside) and the outdoor unit (the compressor and fan outside) constantly send signals to each other through a communication cable, and if the indoor unit stops getting a reply it shuts the system down and shows E1.
The same code can also be caused by:
What each code means can also differ between Alliance models, so check your manual if you have it. In our recent experience, the cause was a damaged communication cable, but the only way to know for sure on your unit is to test it. That's why we always assess before replacing any parts: guessing can mean paying for a new board or sensor you didn't need.
| Cause | Signs | Fix |
|---|---|---|
| Damaged or defective communication cable | E1 returns straight after a reset; cable runs outside, through a wall or past building work | Cable tested and replaced |
| Loose, burnt or corroded terminals | E1 comes and goes, especially in wet weather | Terminals cleaned, re-crimped and tightened |
| Power surge damage | E1 started after load-shedding or a storm | Indoor or outdoor control board tested; repaired or replaced |
| Faulty main control board (PCB), indoor or outdoor | Cable and terminals test fine, but there's still no signal | Board replaced |
| Faulty temperature sensor (thermistor) | Sensor reads open or out of range when tested | Sensor replaced |
| Wiring mistake after an install or move | E1 appeared right after the unit was installed or relocated | Wiring corrected to the diagram |
Don't open the outdoor unit or touch the terminals. The communication cable shares a terminal block with live mains wiring, so testing it is a job for a qualified technician.
A homeowner in Kempton Park called us because their Alliance wall-mounted split had stopped working and the display was showing E1.
Diagnosis: Rather than guessing and swapping control boards, we tested the power supply, the terminals and the signal between the two units. The fault was the communication cable itself: it was defective, so the signal wasn't getting through.
Fix: We replaced the communication cable, secured the connections and tested the system. The E1 error cleared and the aircon started working perfectly again. The customer didn't need a new board or a new aircon.
An E1 error on its own is rarely a reason to replace an aircon. Cable and terminal faults are quick, inexpensive repairs. Even a control board is usually worth replacing on a unit that's otherwise in good condition. Replacement only makes sense when the unit is very old, uses outdated gas, or has several major faults at once. See repair or replace? for the rule of thumb we use.
Call or WhatsApp 072 686 0472 with a photo of the display. Every job starts with a flat R350 diagnostic call-out across Johannesburg, Pretoria, Kempton Park and the East Rand. If a surge caused it, we can also write a surge damage report for your insurer.
By Absolute Repairs · Updated October 2026
E1 is most often linked to a communication fault between the indoor and outdoor units, but depending on the model it can also point to a faulty main control board (PCB), a faulty temperature sensor, or wiring and power supply problems. On our most recent Alliance E1 job in Kempton Park, the cause was a damaged communication cable. Because the same code has several possible causes, an on-site assessment is highly advised before any parts are bought.
Switch the aircon off at the isolator or circuit breaker, wait about five minutes, and switch it back on. If E1 was caused by a power dip it may clear. If it comes back, there is a real fault in the wiring or a control board and a technician needs to test it.
Usually not. E1 is very often a cable or connection fault. On a recent Kempton Park job, replacing a defective communication cable got the Alliance aircon working perfectly again, with no new boards or new unit needed.
Yes. A surge after load-shedding or a storm can damage the communication circuit on the indoor or outdoor control board. If that happens, we can also write a surge damage report for your insurance claim.
Every aircon call-out starts with a flat R350 fee, which covers travel, on-site diagnosis and a fixed quote. A cable or terminal repair costs far less than a control board, which is why the fault should be tested before any parts are bought.
Tell us your suburb, the brand and model, and the fault. Standard R350 diagnostic call-out.
📞 Call 072 686 0472 💬 WhatsApp UsOr email info@absoluterepairs.co.za
Standard R350 Diagnostic Call-Out Fee applies for on-site fault isolation.
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