Do not driveMinutes
J1939 code SPN 1553. Below — how the fault is worded at the factory by International, and what the second half of the code (FMI) means in the standard.
| FMI 0 | HVAC Blower Motor Speed Adjustment — HVAC Blower Speed Analog Input reading above normal range |
| FMI 1 | HVAC Blower Motor Speed Adjustment — HVAC Blower Speed Analog Input reading below normal range |
| SPN 1553 FMI 01553/0 · 1553.0 | data above normal range (most severe level) |
| SPN 1553 FMI 11553/1 · 1553.1 | data below normal range (most severe level) |
Do not drive. Stop as soon as it’s safe to do so — don’t keep going.
The engine is already past its temperature limit. An aluminium head goes fast: first the geometry warps, then the gasket burns through.
Next comes a blown head gasket, a damaged head and, at worst, a cracked block. Shut it down and let it cool — never open the expansion tank cap while hot.
Let the engine cool — never open the expansion tank cap while hot. Then check the level and the hoses.
Scanner threw several codes at once? Paste the whole list — we will show which one is the root cause and which ones simply followed.