Do not driveTo the nearest safe stop
J1939 code SPN 170. Below — how the fault is worded at the factory by Renault Trucks and ZF AS-Tronic, and what the second half of the code (FMI) means in the standard.
| FMI 0 | No battery voltage. Repair: Check the voltage on the control unit pins (X1A/1, X1A/4, X1A/5, X1A/16, X1A/17). Switch the ignition off, switch it on again and repeat the test. If the fault persists, replace the control unit. |
| FMI 3 | Ambient temperature sensor, open circuit or short to positive. Repair: Check the continuity and insulation of the wiring with respect to +24 V (SL1/1, SL1/2). |
| FMI 4 | Ambient temperature sensor, short to ground. Repair: Check the continuity and insulation of the wiring (SL1/1, SL1/2). |
ZF AS-Tronic uses its own fault numbering: the number in the table below is an internal ZF code, not a J1939 SPN. It matches the title of this page by digit only and means something different.
| FMI 0 | No supply voltage on the main relay (terminal 30). |
| SPN 170 FMI 0170/0 · 170.0 | data above normal range (most severe level) |
| SPN 170 FMI 3170/3 · 170.3 | voltage above normal or shorted high |
| SPN 170 FMI 4170/4 · 170.4 | voltage below normal or shorted to ground |
Do not drive. Stop as soon as it’s safe to do so — don’t keep going.
The code is flagged critical: the manufacturer considers it unsafe to keep driving without checking.
This code alone cannot say what will fail next, so stop at the first safe opportunity and look at it on the spot.
That said, the manufacturer flags this code as critical — if in doubt, it is safer to stop and check on the spot.
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.