P0696
Fan 3 Control Circuit High
Powertrain Engine Cooling Fan Control Circuit 🟡 Moderate — Fix within a week
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What This Actually Means
In plain language — no jargon

The cooling fan motor circuit is receiving too much voltage, like a light bulb getting overpowered by excessive electricity. The ECU detected a voltage reading that's higher than expected when trying to control fan speed.

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Symptoms You May Notice
3 known symptoms for this code
Cooling fan runs continuously at high speed
Engine running hot or temperature gauge climbing
Check Engine Light illuminated
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECM monitors the voltage feedback from the Fan 3 control circuit to verify proper fan operation. It expects a specific voltage range when the fan is commanded on or off. A voltage reading above the acceptable threshold triggers this fault, indicating a possible short to power or wiring issue.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Fan Control Voltage 0.5V to 4.5V (circuit dependent) Above 4.8V or shorted to battery voltage
Circuit Resistance 20-100 ohms (motor coil) Below 10 ohms or open circuit
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Battery terminals and connections
Clean and tighten corroded battery terminals and ground connections that could cause high voltage feedback.
2
Fan control relay
Test or replace the relay controlling Fan 3 circuit, as a stuck relay can cause constant high voltage to the motor.
3
Wiring harness and connectors
Inspect the fan motor wiring for exposed copper, pinched wires, or corroded connectors creating a short-to-power condition.