SPN 97
INFO
Water in fuel
The truck's control module (ECU) reports a fault on: Water in fuel.
SPN 97 means a truck control module (ECU) flagged a fault on water in fuel, part of the Fuel system on heavy-duty diesel trucks. DERATE rates it INFO: it does not limit driving; have it checked at the next service. Part usually replaced: Water separator filter, $30–$120 (aftermarket to dealer) plus 0.3–0.8 h labor.
Fuel
Can I keep driving?
Yes. It is informational and does not limit driving; have it checked at the next service.
Part usually replaced
Water separator filter
$30–$120 (aftermarket to dealer)
Labor: 0.3–0.8 h
USD, part only. Labor is billed at the shop's hourly rate.
Data: DERATE verified base, updated October 2026
Related codes
Read it off your own dash
Take one photo and DERATE tells you whether you can keep driving.
Ask DERATE
DERATE assists. It does not replace inspection by a qualified technician.