Parking AC Error Code Reference (E1–E9)

• Table of Contents

1. E1 — Indoor temperature sensor fault
2. E2 — Outdoor / condenser temperature sensor fault
3. E3 — Communication fault (split units)
4. E4 — Fan motor fault
5. E5 — Low refrigerant pressure
6. E6 — Compressor over-current
7. E7 — Low battery voltage
8. E8 — High discharge temperature
9. E9 — EEPROM / control board fault

Vethy parking air conditioners display E1 to E9 fault codes on the remote and the unit panel. This page is the field reference — what each code means, the most likely cause, and the first fix to try before opening a service ticket.

This page is a generic field troubleshooting guide for Vethy 12V/24V parking air conditioners. Always disconnect the battery before opening the unit and follow the install manual that shipped with your specific model. Refrigerant work (R410A) must be performed by a certified technician.

E1 — Indoor temperature sensor fault

The cabin temperature thermistor is open or shorted. Check the sensor connector on the evaporator control board, reseat. If the code persists, replace the sensor (spare-part kit available).

E2 — Outdoor / condenser temperature sensor fault

Roof unit thermistor on the condenser coil is open or shorted. Open the roof cover, check connector seating, replace sensor if needed.

E3 — Communication fault (split units)

The cable between condenser and evaporator on a VX3000SP split unit has a comms break. Check the multi-pin connector on both ends; look for road-debris damage to the cable run.

E4 — Fan motor fault

Indoor or outdoor BLDC fan motor not responding. Cycle power. If persistent, the fan motor needs replacement.

E5 — Low refrigerant pressure

System pressure dropped below safe threshold. Do not attempt DIY refill — call a certified R410A technician. Most often caused by a slow seal leak or transit damage.

E6 — Compressor over-current

Compressor draw exceeded safe current. Causes: heat-soaked unit at extreme ambient (>52 °C), clogged condenser, blocked filter. Clean and retest.

E7 — Low battery voltage

Battery dipped below low-voltage cutoff (11.4 V at 12V, 22.8 V at 24V). Charge battery, increase sleeper bank capacity or run shore power.

E8 — High discharge temperature

Compressor discharge thermistor exceeded safe limit. Often combined with clogged condenser or extreme heat. Let unit cool 30 minutes, clean condenser, restart.

E9 — EEPROM / control board fault

Control board lost configuration. Power-cycle. If persistent, the control board needs replacement (spare-part kit available).

If the problem persists after the steps above, contact Vethy support with the unit serial number, install year and a short video of the symptom: info@vethy.com · Open a support ticket.

Frequently asked questions

Why does my parking AC show E5 in summer only?

E5 in extreme heat with no other fault is often a marginal refrigerant charge that becomes critical at high pressure. Have a certified tech check pressure.

Can I clear an E9 code at home?

Power-cycle clears transient E9. Persistent E9 means the EEPROM lost its settings and the control board needs replacement.

What if I see two codes alternating?

Note both codes and email support. Combined codes usually point to a single root cause (e.g. E5+E8 = condenser issue).

Do you publish a code list per model?

E1–E9 are common across the VS02-PRO, VX3000SP, VM6000 Max and ZH800 platforms. Model-specific extensions are in the install manual.