What Does P2685 Mean?
The PCM has detected abnormally low voltage in the actuator supply voltage "C" circuit. This indicates insufficient power reaching actuators, which can result from excessive current draw, wiring resistance, or power supply problems.
Common Causes
35%
Shorted actuator or solenoid on circuit C drawing excessive current
30%
High resistance in power supply wiring or connections
20%
Weak or failing relay supplying actuator circuit C
15%
Corroded ground connection causing voltage drop
Diagnostic Steps
1
Step 1: Measure voltage at actuator supply circuit C with key on, engine off; should be battery voltage (12-14V)
2
Step 2: Measure voltage drop across power supply circuit under load; should be less than 0.5V
3
Step 3: Disconnect actuators one at a time while monitoring voltage to identify if one is drawing excessive current
4
Step 4: Check resistance of each actuator connected to circuit C; compare to specifications
5
Step 5: Inspect all ground connections related to actuator circuit for corrosion or looseness
Estimated Repair Cost
$120 - $700
Parts + labor, varies by vehicle and location
The PCM has detected abnormally low voltage in the actuator supply voltage "C" circuit. This indicates insufficient power reaching actuators, which can result from excessive current draw, wiring resistance, or power supply problems.
The most common cause of P2685 (Actuator Supply Voltage "C" Circuit Low) is: Shorted actuator or solenoid on circuit C drawing excessive current
Typical repair costs for P2685 range from $120 to $700, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Actuators may operate intermittently or not at all, potentially affecting engine timing, emissions controls, or other critical systems. May cause rough running or reduced power.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2685 to identify the root cause.
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Quick Info
Category
Powertrain
System
Actuator Power Supply Circuit
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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