Introduction

The DTC P0568 trouble code is associated with a problem in the vehicle speed sensor circuit, specifically the Vehicle Speed Sensor (VSS) signal. This sensor is critical to the proper functioning of various vehicle systems, including cruise control and the transmission system. Understanding and resolving this code is essential to ensuring that your vehicle operates safely and efficiently.

DTC Code P0568 Description

Code P0568: Vehicle Speed Sensor (VSS) Circuit High

• System involved: Transmission system, cruise control, engine management system
• Common Symptoms: Engine Light (MIL) on, cruise control malfunction, erratic transmission shifts, acceleration problems
• Main Cause: Vehicle speed sensor signal higher than default values or sensor circuit problems

Vehicle Speed Sensor (VSS) Operation

The vehicle speed sensor (VSS) measures the speed at which the vehicle is traveling and sends this information to the engine control unit (ECU). The ECU uses this data to manage various aspects of the vehicle's operation, including transmission control and cruise control. A VSS signal that is too high may indicate a problem with the sensor itself or with the circuitry that transmits the data to the ECU.

How the VSS circuit works

The vehicle speed sensor is usually mounted on the transmission or input axle. When the vehicle moves, the sensor detects the rotation of the components and converts this information into an electrical signal. This signal is then sent to the ECU. If the signal received by the ECU is higher than expected, the DTC code P0568 is generated.

Causes of Code P0568

The DTC code P0568 can be caused by various problems, including:

1. Vehicle speed sensor faulty: The sensor itself may be damaged or faulty, generating an abnormal signal.
2. Wiring or connector problems: The wires or connectors connecting the sensor to the ECU may be damaged, worn, or corrupted.
3. Ground Problems: A poor ground connection can affect the sensor signal, causing incorrect readings.
4. ECU Malfunction: In rare cases, a problem with the engine control unit can cause the VSS signal to be misinterpreted.
5. Transmission Faults: Mechanical or installation problems in the transmission can affect the operation of the speed sensor.

Symptoms of Code P0568

When DTC code P0568 occurs, symptoms may vary depending on the severity of the problem. The most common symptoms include:

• Engine Warning Light (MIL): The engine warning light comes on on the dashboard to indicate a problem.
• Cruise Control Malfunction: The cruise control system may not function properly, causing difficulty maintaining a constant speed.
• Irregular Transmission Shifts: The transmission may shift gears erratically or not respond properly to commands.
• Acceleration Problems: The vehicle may exhibit erratic acceleration or not respond as expected.
• Difficulty shifting gears: Gear shifting may be more difficult or may not occur smoothly.

Diagnostic Procedure

To fix the P0568 code, you need to perform a thorough diagnosis by following the steps below:

1. Reading the error code

Use an OBD-II scanner to confirm the presence of the P0568 code and check for other related codes. This will help identify any additional issues that may be affecting the system.

2. Visual inspection of the sensor and wiring

Check the vehicle speed sensor and associated wiring for obvious damage or signs of wear. Examine the connectors for any signs of corrosion or looseness.

3. Speed sensor test

Use a multimeter to test the speed sensor. Measure the resistance and see if the sensor produces the correct signal when the vehicle is moving. Consult the manufacturer's manual for specific reference values.

4. ECU signal check

If the sensor appears to be working properly, verify that the signal transmitted to the ECU is stable and correct. Use an advanced diagnostic tool to monitor the sensor signal in real time.

5. Mass system check

Make sure all ground connections are secure and in good condition. A ground problem can cause the sensor to give incorrect readings.

6. Transmission control

Inspect the transmission for any mechanical or installation problems that could affect the operation of the speed sensor.

Solutions and Repairs

Once you have identified the cause of the P0568 code, you can take the following steps to resolve the issue:

1. Replacing the speed sensor

If the speed sensor is faulty or defective, replace it with a new one. Make sure you use a replacement sensor that meets the manufacturer's specifications.

2. Wiring and connector repair

Repair or replace damaged or corroded cables and connectors. Make sure all connections are secure and free of rust.

3. Mass check and repair

Correct any ground problems in the vehicle's electrical system. A solid ground connection is essential for proper sensor operation.

4. Transmission control and maintenance

Make sure the transmission is in good condition and that there are no mechanical problems that could affect the speed sensor.

5. Repair or replacement of the ECU

If all physical components are in good condition but the problem persists, the engine control unit may need to be repaired or replaced.

Prevention

To prevent the P0568 code from recurring, follow these preventative practices:

1. Regular Sensor and Wiring Maintenance: Periodically check the speed sensor and its wiring for signs of wear or damage.
2. Electrical System Check: Make sure the vehicle's electrical system, including ground connections, is in good condition.
3. Transmission Check: Keep your transmission in good condition to prevent problems that may affect the speed sensor.

Conclusions

DTC P0568 indicates a problem with the vehicle speed sensor circuit, which can affect the operation of the transmission and cruise control. Identifying and fixing the problem requires a thorough diagnosis of the sensor, wiring, and engine control unit. By following the diagnostic steps and taking the appropriate solutions, you can resolve the P0568 code and ensure safe and reliable operation of your vehicle.