Reading the Power LED
All states below are solid, not flashing. The color tells you the story.
| Color | Meaning | What we'd check |
|---|---|---|
| Off | No power | Ignition feed, main power and ground, fuses |
| Red | System error | Power cycle, then contact us if it stays red |
| White | Normal operation | Nothing, you're good |
| Green | Normal, but running v3 firmware that needs NSP to talk to it | Connect with NSP instead of ESP |
| Blue | Boot mode or firmware update running | Wait, and don't cut power |
Things worth knowing
A dead LED is almost always a wiring issue, not a faulty ECU. Check with a meter for 12 V on the ignition input and a solid ground before anything else.
Blue means firmware is being written. Losing power now can leave the ECU needing recovery, so keep the battery healthy and the key on until it finishes.
If the LED is green and ESP won't connect, that's expected: the ECU is on firmware that talks to NSP. Use NSP.
The Status LED next to it has its own set of meanings, and the USB port article helps when the laptop won't connect. If you're stuck on a red LED, contact us.
