Safe to driveTo the nearest safe stop
J1939 code SPN 604. Below — how the fault is worded at the factory by International and Renault Trucks, and what the second half of the code (FMI) means in the standard.
| FMI 2 | Transmission Neutral Switch — Transmission Auto Neutral Enable Switch Error |
| FMI 7 | Neutral switch stuck in the open or the closed position. Repair: Check the switch and the wiring (SL4/5). |
| FMI 18 | The speed sensor sends data that the VECU processor reads as a loss of communication with the speed sensor. Repair: Check the speed sensor connections. |
| SPN 604 FMI 2604/2 · 604.2 | data erratic or intermittent |
| SPN 604 FMI 7604/7 · 604.7 | mechanical system not responding |
| SPN 604 FMI 18604/18 · 604.18 | below normal — moderate severity |
Safe to drive. Below — how much time you have and what happens if you keep going.
The gearbox or clutch has gone into limp mode: some gears may be unavailable and an automated box may stop shifting under load.
The main risk is being left on a climb with no gear and rolling back. Do not take a loaded truck into the hills; reaching level ground and a shop is fine.
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.