Powertrain, generic · Auxiliary emission controls

P0484 Fan Circuit Current High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P0484 monitors the current drawn in the fan's load circuit: if it exceeds a threshold – blocked or stiff motor, shorted turns, a short in the load circuit – the code sets. This is only possible where the fan runs on a current-measuring semiconductor driver or fan module; plain relay circuits do not measure load current. Supplier patents (Bosch and others) describe current limiting or switch-off after a few seconds of overcurrent, ignoring the inrush current. No manufacturer table available to us lists P0484, so thresholds and warning-lamp behaviour remain open; CARB requires output components to be monitored.

Likely causes

Fan motor stiff (bearing damage) or blocked (foreign object, ice, bent blade)
Shorted turns or worn brushes in the fan motor
Short in the load circuit (pinched or chafed wire)
Fan control module faulty (wrong current measurement)

Symptoms

  • Warning lamp (depending on the maker)
  • Fan does not run, runs only briefly or at reduced power
  • Humming or grinding at the fan, possibly blown fan fuse
  • Overheating at standstill

Repair estimate

DifficultyMediumDIY possible
Parts and labour€120–700
Time0.8–3 h

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

Parts involved

cooling fan motorfan control modulefan power circuitengine control module

Related codes

P0485P0483P0494P0480P0691

References: law.cornell.edu, patents.google.com, patents.google.com.