Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there's a problem with the sensor that helps the car's computer control how fast the engine runs when the car is not moving. It's like if your heart rate monitor was giving the wrong signals.
The code P256C is triggered when the Engine Control Module (ECM) detects a low voltage signal from the engine idle speed selector sensor or switch circuit.
P256C indicates that the ECM has detected a low voltage condition in the circuit responsible for monitoring the engine idle speed selector sensor or switch. This sensor or switch is crucial for maintaining the correct engine idle speed by providing feedback to the ECM.
• Engine idles erratically
• Check Engine Light is on
• Poor fuel economy
• Faulty engine idle speed selector sensor
• Damaged or corroded wiring or connectors
• Faulty ECM
ECM: Engine Control Module
OBD-II: On-Board Diagnostics II
• Use an OBD-II scanner to confirm the code.
• Inspect wiring and connectors for damage or corrosion.
• Test the engine idle speed selector sensor for proper operation.
• Replace the faulty engine idle speed selector sensor.
• Repair or replace damaged wiring or connectors.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Screwdriver set
$100 - $300
Moderate
• Ford F-150
• Chevrolet Silverado
• Toyota Camry
• Regularly inspect and maintain engine sensors.
• Keep electrical connections clean and secure.
• Follow scheduled vehicle maintenance.
Sensor Issue
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional mechanic.
• Avoid driving at high speeds until the issue is resolved.
Check with your vehicle manufacturer, as sensor-related issues may be covered under warranty.
This code has been associated with issues in vehicles with electronic throttle control systems, particularly in models with high mileage.
Moderate – It can affect engine performance and fuel efficiency, so it should be addressed soon.
Driving with a malfunctioning sensor can lead to increased emissions and may not comply with emission regulations.
• Engine at operating temperature
• Vehicle at idle
The engine idle speed selector sensor is typically located near the throttle body or on the intake manifold.
Q: Can I drive with a P256C code?
A: It's not recommended to drive for extended periods with this code, as it can lead to poor engine performance and increased emissions.
Q: How can I reset the Check Engine Light after fixing the issue?
A: You can use an OBD-II scanner to clear the code after the repair, or disconnect the battery for a few minutes to reset the system.
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