Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer isn't getting any information from the sensor that tells it how fast the back left wheel is spinning.
The vehicle's control module is not receiving a signal from the rear left wheel speed sensor via the Controller Area Network (CAN).
The P1774 code indicates a loss of communication or no signal from the rear left wheel speed sensor to the vehicle's electronic control unit (ECU) over the CAN bus. This could be due to a faulty sensor, wiring issues, or a problem with the ECU.
• ABS warning light on
• Traction control system malfunction
• Inaccurate speedometer readings
• Faulty rear left wheel speed sensor
• Damaged or corroded wiring/connectors
• Faulty ECU
CAN: Controller Area Network, a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other.
ECU: Electronic Control Unit, a type of computer used in vehicles to manage various systems.
• Inspect the rear left wheel speed sensor for damage.
• Check the wiring and connectors for corrosion or damage.
• Use a scan tool to check for additional error codes.
• Replace the rear left wheel speed sensor if faulty.
• Repair or replace damaged wiring/connectors.
• Reprogram or replace the ECU if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $400
Moderate
• Vehicle 1
• Vehicle 2
• Vehicle 3
• Regularly inspect wheel speed sensors and wiring.
• Keep connectors clean and free of corrosion.
• Perform routine maintenance checks.
Sensor Issue
• Avoid driving at high speeds until the issue is resolved.
• Have a professional inspect the vehicle if you're unsure about the repairs.
Check with your vehicle manufacturer for specific warranty coverage on sensors and electronic components.
This code has been associated with issues in vehicles with older sensor technology and CAN systems.
Moderate – While the vehicle can still be driven, safety systems like ABS and traction control may not function properly.
Driving with a malfunctioning wheel speed sensor can affect braking performance and vehicle stability.
• Vehicle must be driven to replicate the issue.
• Ensure the vehicle is on a flat, safe surface for testing.
The rear left wheel speed sensor is located at the wheel hub of the rear left wheel.
Q: Can I drive with a P1774 code?
A: It's not recommended to drive for long periods with this code as it can affect braking and stability systems.
Q: How do I reset the P1774 code?
A: After repairing the issue, use an OBD-II scanner to clear the code from the vehicle's computer.
Pro · Four-system diagnostics
A handheld scanner aimed at engine, transmission, ABS, and airbag diagnostic work.
Chassis and ABS faults usually need a scanner that can read brake-system data directly.
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Universal · Torque wrench
Useful when reassembly torque matters for wheel, suspension, and under-hood fasteners.
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