P0693
Fan 2 Control Circuit LowP0693 is a generic OBD-II powertrain diagnostic trouble code: Fan 2 Control Circuit Low. It is logged by the engine control unit when the glow monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0693 means
DTC P0693 — Cooling Fan 2 Control Circuit Low — is a SAE generic powertrain code stored by the ECM when it detects that the control circuit for the secondary (number 2) engine cooling fan is operating at an abnormally low voltage. In most implementations the ECM drives the fan via a relay or a PWM-controlled driver; when the commanded output goes high but the feedback circuit reads near ground potential, the ECM interprets this as a short to earth (ground) in the fan motor winding, driver circuitry, or control wiring, and stores P0693.
The secondary cooling fan supplements the primary fan, typically activating at higher coolant temperatures, when the A/C compressor is running, or during low-speed driving conditions where ram airflow through the radiator is insufficient. A failed cooling fan circuit can allow engine temperatures to climb above the normal operating range, particularly during city driving or when stationary with the A/C on. In vehicles with electric radiator fan systems this is especially critical because no mechanical belt-driven fan provides a fallback.
P0693 is a serious warning because sustained engine overheating damages head gaskets, cylinder heads, and catalytic converters. The ECM may command the cooling fan to run continuously or limit A/C compressor engagement as a self-protection measure. Diagnosis should be performed promptly, particularly before summer driving conditions.
Common causes
Most-frequently reported root causes when P0693 is logged.
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1
Fan motor 2 winding short to earth — internal motor failure collapsing the control circuit voltage (most common)
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2
Chafed, pinched, or damaged control wiring between ECM/driver and fan motor creating a short to chassis ground
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3
Corroded or flooded fan motor connector allowing current leakage to ground
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4
Failed cooling fan relay with internal short pulling the output low regardless of ECM command
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5
Faulty ECM/PCM output driver for the fan 2 control channel
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6
Incorrect aftermarket fan motor installed with incompatible resistance or winding specification
Symptoms drivers notice
How to diagnose P0693
A typical diagnostic flow when this code is present.
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1
Confirm the code with a scan tool; note engine coolant temperature at time of fault and any co-stored overheating or A/C codes
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2
Visually inspect the fan 2 motor, wiring harness, and connector for physical damage, melting, corrosion, or contact with hot components
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3
Disconnect the fan motor connector and measure resistance from the control terminal to chassis ground — a very low reading (near 0 Ω) with the connector unplugged confirms an internal motor winding short
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4
With the motor connector unplugged, re-check the control circuit at the harness side for the same low-resistance short to ground; if present, trace the wire for damage between ECM and fan
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5
Check the cooling fan relay — swap with an identical relay from another circuit and retest; measure relay coil and contact resistance
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6
Command the fan on via the scan tool's actuator test with the circuit fully reconnected; verify actual fan operation and monitor circuit voltage at the fan connector
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7
Replace the fan motor if winding resistance is out of specification; repair wiring if the short is in the harness; replace relay if faulty
Vehicles where we've handled P0693
Platforms in our catalogue with confirmed P0693 coverage.
Related powertrain codes
Frequently asked questions
Is P0693 dangerous to ignore?
Yes. Without cooling fan 2 operating, the engine can overheat during low-speed driving, prolonged idling, or in hot weather — especially with A/C running. Overheating can destroy head gaskets and warp cylinder heads, leading to repair costs far exceeding the fan motor replacement.
What is the difference between P0691, P0692, and P0693?
P0691 is Cooling Fan 1 Control Circuit Low, P0692 is Cooling Fan 1 Control Circuit High, and P0693 is Cooling Fan 2 Control Circuit Low. The number (1 or 2) identifies which fan circuit is at fault; 'low' means a short-to-ground or excessive current draw; 'high' means an open circuit or short to voltage.
Can a bad relay cause P0693 without the fan motor being faulty?
Yes. A cooling fan relay with a shorted contact or a failed driver circuit inside the relay module can hold the circuit in a low-voltage state and trigger P0693 even if the fan motor itself is healthy. Always test the relay before condemning the motor.
Will P0693 affect my A/C performance?
Likely yes. On most vehicles the secondary cooling fan also cools the A/C condenser. With fan 2 inoperative, A/C efficiency drops and the ECM may proactively disengage the compressor clutch to prevent refrigerant pressure overload — resulting in reduced or absent A/C cooling.
Disabling P0693 in software
RaceTune can permanently disable P0693 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
ECUs with a P0693 disable in our catalogue
Confirmed coverage from our recipe database — we support many more families. Upload your file and our identifier will match it automatically.
- Bosch EDC17C74 verified 1 software version
- Bosch EDC17CP44 verified 1 software version
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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