Powertrain, generic (extended)

P2C40 Fan 4 Control Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2C40 states that fan control output 4 is held at too high a level: the line has contact with battery voltage, or the driver cannot pull it down when it should. In Saab's 2011 9-5 the counterpart relay codes P0692, P0694 and P0696 stand for a relay control wire shorted to a voltage source, and the manual adds that a stage stuck on can also occur without any stored code. No manufacturer publicly documents P2C40. Typical finds are insulation worn through against a live wire, moisture bridging two pins and a defective relay or fan module input. The fan may run without pause, even after the engine is off, or not respond at all, and a fan that keeps turning can flatten the 12 V battery. Low voltage is P2C3F, the general circuit fault P2C3E.

Likely causes

Fan 4 control wire in contact with a battery-voltage circuit
Relay or fan module input failed internally
Moisture bridging pins in the connector

Symptoms

  • Fan 4 runs constantly, sometimes after switch-off
  • Discharged 12 V battery after standing
  • Check engine light

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–400
Time0.5–2.5 h

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

Parts involved

cooling fan 4fan relay 4ecm

Related codes

P2C3EP2C3FP2C42P0696P0692

References: law.cornell.edu, saabwisonline.com.