Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P0526 Fan Speed Sensor Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

Engine-driven fans with an electronically controlled viscous clutch (GM petrol SUVs and pick-ups 2004–2006, GM Duramax, Ford 6.7 L Power Stroke) have a Hall sensor reporting fan speed; the fan checks P0483, P0494 and P0495 need it. P0526 means no usable signal although the clutch is driven: GM Duramax below 500 rpm with fan duty at least 36 % for 2 s; the 6.6 L LML distinguishes a level stuck low or high; GM petrol V8s set it when no pulses arrive with the engine running. Type B, two trips. GM also reports a missing signal under P0526. A GM bulletin for 2011–2013 Duramax vans and pick-ups names loud fan noise and weak air conditioning at low speed.

Likely causes

Hall sensor at the fan clutch faulty
Wiring or connector (chafing at the shroud, corrosion)
Clutch not turning despite command
Engine module or supply

Symptoms

  • Check engine light on
  • Fan permanently on or off, loud fan noise
  • Weak air conditioning at low speed, overheating under load

Repair estimate

DifficultyMediumDIY possible
Parts and labour€80–700
Time0.5–2.5 h

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

Parts involved

fan speed sensorviscous fan clutchsensor wiringengine control module

Related codes

P0527P0528P0529P0483P0494P0495

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.