Network, generic (extended)

U350E Control Module Cooling Fan Circuit High

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

U350E points to a fan circuit whose level is higher than the module expects, typically because the control or feedback line is shorted to battery voltage or the output stage is stuck on. Unlike the low and open faults, the fan may then run all the time, even with the module cold or the car parked, which is audible and can drain the 12 V battery. Fan-cooled electronics are found in infotainment units such as the central unit of the Karma Revero (TB-24-94-01) and in on-board chargers; CARB treats electrical cooling outputs for inverters and batteries as monitored components. U350E is not documented by any manufacturer in public. Check the harness for chafing against supply wires before suspecting the module.

Likely causes

Fan control or feedback wire shorted to a 12 V supply
Fan output stage in the module stuck on
Moisture or corrosion bridging pins in the fan connector

Symptoms

  • Module fan running continuously, also after switch-off
  • 12 V battery discharged after standing
  • Fan does not react to temperature changes

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€30–500
Time0.5–2.5 h

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

Parts involved

module cooling fanfan wiring

Related codes

U350CU350DU350FP0692

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