Disc ESC Disconnected error on the EAV J150, working the nozzle signal path from the CPU out to the nozzle ESC

Please follow the steps below to resolve this issue.

IF YOU RECEIVE THE FOLLOWING ERROR:

Disc ESC disconnected — Nozzle atomizer signal lost

The disc in this error is the spray nozzle's centrifugal atomizer disc, not a propeller motor. The error means the flight controller has lost signal from one specific nozzle ESC.

Complete the steps below to resolve the error and get your drone back in the air

Key Steps

1. Identify the Reported Position

Note which nozzle position the error reports, for example left rear. Troubleshooting is done per-position, and every step below applies only to that nozzle.
Working backward from the CPU to the nozzle, the signal path for that position has four points: the CPU connector, the frame cable, the harness run along the arm, and the nozzle ESC connector.

2. Power Cycle the Drone

Turn the main battery off.
Unplug the internal battery.
Wait 30 seconds.
Plug in the internal battery.
Turn the main battery back on.
This clears transient CPU communication faults.
If the error clears, log the event and watch the next flight. If it returns in the same position within a few flights, treat it as a connector or harness issue, even though it cleared once.
If the error is still present, continue to Step 3.

3. Inspect the Connector and Harness

Inspect the nozzle ESC connector for bent pins, corrosion, or incomplete seating.
Check the heat-shrink coverage along the harness run on the arm.

4. Replace a Damaged Connector or Harness Segment

If you find damage or a break, replace the affected connector or harness segment.
Confirm continuity again before test-arming.
If no damage or break is found, continue to Step 5.

5. Swap the Nozzle Assembly

Move a confirmed-working nozzle assembly into the affected position, or move the suspect assembly to a known-good position. This isolates whether the fault is in the assembly itself or upstream of it.
Swap either left and right sides or front and back, depending on which positions are working and which are not.
If the fault follows the assembly, the fault is in the assembly. Check both the nozzle ESC and the nozzle motor, and replace the assembly.
If a known-good nozzle assembly does not clear the error, the fault is upstream. Continue to Step 6.

6. Swap the Solenoid

Swap the solenoid from a known-good position into the affected position.
If the fault follows the solenoid, replace the solenoid.
If a known-good solenoid does not clear the error, the fault is in the wiring. Continue to Step 7.

7. Replace the Wiring

Replace the arm signal harness first.
If the error is still present, replace the spray power wiring.

8. Verify

Power cycle the drone and check that the error message is gone.
Confirm the nozzle at the affected position atomizes before returning the drone to work.

The drone should now be ready for takeoff.

Cautionary Notes

Troubleshoot one position at a time. Label every part you move so you know which assembly came from where — a swap you cannot reverse turns one bad position into two.
An error that clears on a power cycle and returns on the same position is a connector or harness fault, not a one-off. Do not write it off because it went away once.
A break inside heat shrink is not visible. Run the continuity check even when the connector looks clean.
Confirm continuity after reseating or replacing anything, before test-arming.

Tips for Efficiency

Swapping against a known-good position is faster than bench-testing parts in isolation, and it tells you whether the fault travels with the part or stays with the position.
Start your inspection at the nozzle ESC connector. It is the most exposed point in the run and the most common place to find corrosion or a partially seated pin.
Keep one known-good nozzle assembly on the shelf as a dedicated test part.