Powertrain, generic · Computer and auxiliary outputs

P0691 Fan 1 Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

The engine module switches the radiator fan relays (or the input of a PWM fan module) through output drivers and checks each control circuit electrically. GM sets a short to ground or voltage at 0.5 Ω or less after 50 of 63 samples, with the lamp after two trips; GM Europe's 2011 Saab 9-5 covers P0691–P0696 with relay assignments, the Saab 9-4X's PWM fan module reacts within 1 s. P0691 means the fan 1 control circuit is shorted to ground. GM fixed a related problem with bulletin 16-NA-123, Ford with SSM 47999 for the 6.7 L diesel. The former title 'Cooling Fan 1' was shortened to the J2012 wording, as for P0480.

Likely causes

Control wire to fan relay or module shorted to ground (chafing)
Water or corrosion in fan or relay connector
Fan relay faulty (coil shorted or low-resistance)
Engine module driver faulty

Symptoms

  • Check engine light (GM after two trips)
  • Fan runs constantly or not at all, depending on circuit design
  • Rising coolant temperature in traffic or with A/C on
  • A/C may be switched off to protect the engine

Repair estimate

DifficultyEasyDIY possible
Parts and labour€20–400
Time0.3–2 h

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

Parts involved

cooling fan relayfan control circuitengine control module

Related codes

P0480P0692P0693P0695P0483P0494

References: law.cornell.edu, gsi.ext.gm.com, gsi.ext.gm.com, saabwisonline.com.