P0649 Speed ​​control indicator control circuit malfunction

P0649 – OBD-II Trouble Code Technical Description

Trouble code P0649 indicates that the powertrain control module (PCM) or one of the vehicle's auxiliary control modules has detected a malfunction in the cruise control indicator control circuit.

What does the fault code mean P0649?

Trouble code P0649 indicates that a malfunction has been detected in the cruise control indicator control circuit by the powertrain control module (PCM) or one of the vehicle's accessory control modules. Errors may also appear along with this error: P0648 и P0650.

Possible reasons

Some of the possible causes of the P0649 trouble code are:

• Defective or damaged speed control indicator (cruise control).
• Problems with the electrical circuit connecting the PCM or other control modules to the cruise control indicator.
• Incorrect operation of the PCM or other control modules related to the operation of the cruise control system.
• Short circuit or broken wiring in the control circuit.
• Problems with ground wire or grounding.
• There is a problem with the cruise control system itself, such as the speed sensor or cruise control switch.

The above reasons can be individual or combined with each other. To accurately determine the cause of the malfunction, it is recommended to conduct a detailed diagnosis of the vehicle.

What are the symptoms of a fault code? P0649?

Symptoms for DTC P0649 may include the following:

1. Check Engine Light: When a P0649 code appears, the Check Engine light on your vehicle's dashboard may illuminate, indicating a problem.
2. Cruise control function unavailable: If the problem is with the cruise control system, the function may not turn on or may not operate normally.
3. Loss of speed stability: In case the cruise control indicator does not work correctly due to a malfunction, it may cause the vehicle speed to become unstable when using the cruise control.
4. Other symptoms: Depending on the specific cause of the error, other symptoms related to faulty electrical circuits or control modules may also be observed.

It is important to note that symptoms may vary depending on the make and model of the vehicle, as well as the specific cause of the error.

How to diagnose a fault code P0649?

The following steps are recommended to diagnose DTC P0649:

1. Checking the error code: You should first use an OBD-II scanner to read the P0649 error code and any other related codes that may help determine the problem.
2. Visual inspection of wires and connections: Inspect the wires and connectors associated with the cruise control system and PCM (Powertrain Control Module) for visible damage, corrosion, or breaks.
3. Voltage test: Using a multimeter, check the voltage at the cruise control indicator control circuit. Make sure the voltage meets the manufacturer's specifications.
4. Checking relays and fuses: Check the condition of the relays and fuses associated with the cruise control system. Make sure they are functioning properly and not damaged.
5. Control module diagnostics: If necessary, perform additional diagnostics on the PCM and control modules associated with the cruise control system to identify possible problems.
6. Checking actuators and sensors: Check the condition of the cruise control actuators and sensors for damage or malfunction.
7. Functionality testing: Once the problems have been resolved, you should test the functionality of the cruise control system to ensure that it is operating correctly and that there are no additional errors.

In case of difficulties or the need for more detailed diagnostics, it is recommended to contact a certified automotive technician or car service center.

Diagnostic errors

When diagnosing DTC P0649, the following errors may occur:

1. Skipping a visual inspection: Failure to visually inspect wires and connectors may result in missing damage or corrosion that could be causing the problem.
2. Insufficient voltage check: Incorrectly measuring or interpreting the voltage on the cruise control circuit may result in an incorrect diagnosis.
3. Problems with relays and fuses: Relays and fuses are not always fully checked, which can lead to undiagnosed problems.
4. Insufficient diagnostics of the PCM and other control modules: Problems with the PCM or other control modules related to the cruise control system may be missed if not properly diagnosed.
5. Problems with actuators and sensors: Cruise control actuators and sensors are not always fully checked, which can lead to undiagnosed problems.
6. Incorrect functionality testing: Sufficient testing of the functionality of the cruise control system is not always carried out after the problem is resolved, which may lead to the error reoccurring.

In general, errors in diagnosing the P0649 trouble code can occur due to lack of care, incomplete analysis, or misinterpretation of diagnostic results.

How serious is the fault code? P0649?

Trouble code P0649 indicates problems with the cruise control indicator control circuit. In most cases, this is not a critical problem and does not affect the safety of the vehicle. However, turning off cruise control can cause additional inconvenience during long journeys on highways.

Although this problem is not likely to have serious safety consequences, it is recommended that the problem be diagnosed and corrected as soon as possible to restore normal operation of the cruise control system and avoid further inconvenience while driving.

What repair will help eliminate the code? P0649?

The following steps are recommended to resolve DTC P0649:

1. Check the electrical connections: The first step is to check the electrical connections, including the connectors and wiring associated with the cruise control system. Make sure all connections are secure and there is no damage to the wiring.
2. Check the relay: Check the status of the relay that controls the cruise control system. Check that the relay is working properly and shows no signs of wear or damage.
3. Electrical Diagnosis: Diagnose the electrical components of the cruise control system, including the steering wheel switches and sensors associated with the cruise control system.
4. Check Engine Control Module (PCM): If the previous steps do not identify the problem, you should check the Engine Control Module for failure or damage. Replace the PCM if necessary.
5. Repair or replace damaged components: If damaged components are found, they should be repaired or replaced in accordance with the manufacturer's requirements.

After completing these steps and eliminating the cause of the problem, you should clear the error code from the PCM memory using a diagnostic scan tool.

What is P0649 Engine Code [Quick Guide]

P0649 – Brand-specific information

Trouble code P0649, which is related to the cruise control system, can be found on various makes of cars, some of them are:

• Ford: This brand uses the designation P0649 for cruise control related errors.
• Chevrolet (Chevy): Some Chevrolet models may also display trouble code P0649, indicating problems with the cruise control.
• Toyota: Some Toyota models may also experience errors related to the cruise control system, which may correspond to code P0649.
• Honda: Some Honda models may also experience similar errors related to cruise control.
• Volkswagen (VW): Some Volkswagen models may also display error codes corresponding to problems with the cruise control.
• Nissan: Some Nissan models may also experience errors related to the cruise control system.

These are just a few examples of vehicle brands that may display the P0649 trouble code. For more accurate information about faults and their meanings, it is recommended to consult the service manual for the specific make and model of your car.