Network, generic (extended)

U350F Control Module Cooling Fan Circuit Range/Performance

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

U350F means the fan circuit is electrically sound but the fan does not do what it is told: its speed feedback disagrees with the command, or the module keeps heating up although the fan is switched on. Dust, a blocked or rubbing blade, worn bearings or a lost speed signal are typical. A related case is Toyota's bulletin T-SB-0021-21 for the 2021 RAV4 Prime: the charger fan's speed sensor reported no signal (P1CE931), charging took longer, and the cure was new charger software rather than a new fan. Karma fixed noise from the infotainment unit fan with a redesigned shroud (TB-24-94-01). CARB asks for a functional check of cooling performance where feasible. No maker lists U350F itself; U350C to U350E cover wiring faults.

Likely causes

Fan blade blocked by dust, debris or a deformed shroud
Worn fan bearing slowing the fan down
Fan speed sensor signal missing or misread
Module software misjudging the fan feedback (Toyota RAV4 Prime charger)

Symptoms

  • Fan noise, rattling or whining from the module
  • Module runs hot, charging or function slowed
  • Code returns after clearing once the fan is commanded again

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–500
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

module cooling fan

Related codes

U350CU350DU350EP0480

References: static.nhtsa.gov, static.nhtsa.gov, law.cornell.edu.