P0694

P0694 is Fan 2 control circuit high - an open or short-to-power on the secondary fan control wire. Cheapest-first ladder: key-on engine-off, measure the fan 2 control wire at the relay/FCM connector; it should sit at battery voltage uncommanded (12.6 V key-on, 13.8 to 14.2 V running) and drop to 0 V when the scan tool commands the fan on. If it stays at battery voltage even when commanded on, the PCM driver is open or the wire is broken between PCM and relay. Measure relay coil resistance (50 to 90 ohms); infinite reading confirms an open coil. On PWM fan 2 systems, watch the FCM input drive line with the scan tool commanding incremental duty cycle and confirm the waveform is clean; a flat-high reading at all commanded duties points to FCM internal fault or open input. Current draw at commanded fan-on should ramp from 3 A inrush to 4 to 15 A steady on a 14 to 16 inch electric fan; less than 1 A current with a healthy command waveform points to a failed fan motor (open brush or burned winding) rather than a control fault. Expensive-misdiagnosis caveat: fan resistor packs are the common consumable on multi-speed fan systems. Ford, GM, and Toyota all use 3-step fan resistor packs that burn open at the high-current stage; the failure mode that drives P0694 specifically is the pack going completely open after the high-stage solder tab unsoldered, which makes the PCM see no return current path and flag the control circuit as high/open even though the relay and PCM are both fine. Pull the pack and ohm each stage before condemning anything upstream; replace the pack, $40 to $120.

Vehicle-specific patterns: 2011-2014 Ford F150 5.0 Coyote single-PWM-fan setup doesn't typically throw P0694; if it does, it's an FCM internal fault and FCM replacement is the fix, $150 to $260. 2007-2014 GM Silverado/Tahoe/Yukon dual-system trucks throw P0694 from the secondary fan motor failing open internally (brush wear, broken solder at commutator) - verify with current clamp on the power feed at command, $180 to $400 fan motor. 2007-2017 Toyota Camry V6 2GR-FE dual fan with resistor pack throws P0694 from the pack high-stage open (most common) or from the fan 2 motor brushes worn out after 150k miles; $50 to $320 depending on which. 2006-2015 Honda Pilot/Odyssey J35 V6 dual-fan throws P0694 from the auxiliary fan relay opening internally after road salt exposure to the underhood fuse block, $30 to $80 relay. Estimated repair: $30 to $400.