P0377 High resolution B signal phase control - too few pulses

P0377 – OBD-II Trouble Code Technical Description

Trouble code P0377 is a general code that indicates that the PCM has detected a problem with the vehicle's timing system high resolution reference “B” signal.

What does the fault code mean P0377?

Trouble code P0377 indicates a problem with the vehicle's timing system high resolution reference “B” signal. This means that the engine control module (PCM) has detected an abnormality in the high-resolution timing signal (too few pulses) that is sent by the optical sensor mounted on the fuel pump. Trouble code P0377 indicates that the number of pulses detected by the sensor does not match the number of pulses expected for proper operation of the engine timing system.

Possible reasons

Some possible reasons for the P0377 trouble code:

• Optical sensor malfunction: The optical sensor that sends high-resolution signals may become damaged or fail due to wear, corrosion, or other problems.
• Problems with wiring and connectors: Breaks, corrosion, or poor connections in the wiring or connectors between the optical sensor and the engine control module (PCM) can cause P0377.
• Mechanical problems with the sensor disk: The sensor disk on which the signal is read may be damaged, misaligned, or dirty, preventing the signal from being read correctly.
• Problems with the engine control module (PCM): Malfunctions or errors in the operation of the PCM itself can lead to a P0377 code.
• Problems with the fuel injection system: A discrepancy in the number of pulses on the sensor dial can be caused by problems with the fuel injection system, such as faulty injectors or fuel pressure regulator.
• Other electrical or mechanical problems: In some cases, other problems, such as problems with the vehicle's electrical system or mechanical problems, can cause the P0377 code.

To accurately determine the cause of the error, it is recommended to conduct a detailed diagnosis using diagnostic equipment or contact a qualified auto mechanic.

What are the symptoms of a fault code? P0377?

Symptoms for DTC P0377 can vary depending on the specific circumstances and nature of the problem, some of the possible symptoms are:

• The Check Engine light comes on: One of the most common signs of a problem is the Check Engine light on your car's dashboard coming on.
• Loss of power: Engine timing problems can cause loss of power or rough running of the engine.
• Unstable idle: The idle speed may become unstable or even disappear.
• Increased fuel consumption: Timing signal mismatch may cause the fuel injection system to operate ineffectively, which may increase fuel consumption.
• Uneven engine operation: The engine may experience jerking or rough operation when accelerating or driving.
• Problems with starting the engine: In some cases, especially if the problem is critical, the car may have difficulty starting or may not start at all.

These symptoms may manifest differently depending on the specific cause of the error and the characteristics of the particular vehicle. If you notice the symptoms above and your check engine light comes on, it is recommended that you immediately contact a qualified auto mechanic to diagnose and repair the problem.

How to diagnose a fault code P0377?

The following approach is recommended to diagnose DTC P0377:

1. Scan error code: Using a diagnostic scan tool, it is necessary to read the error codes from the PCM memory. This will help confirm the presence of the P0377 code and identify other possible related errors.
2. Checking wiring and connectors: Check the wiring and connectors connecting the optical sensor to the PCM. Pay attention to breaks, corrosion, overheating and other damage that may interfere with signal transmission.
3. Checking the optical sensor: Check the condition and correct installation of the optical sensor. Make sure it is not damaged or littered. Check its resistance and output signals.
4. Checking the sensor disc: Check the condition and correct installation of the sensor disk. Make sure it is not damaged, dislodged or littered.
5. Checking the Engine Control Module (PCM): Run a diagnostic on the PCM to ensure it is operating properly. Check its connections, update the software if necessary.
6. Additional tests and measurements: Depending on the results of the previous steps, additional tests and measurements may be required, such as checking power and ground circuits, checking sensor signals on the control unit, etc.
7. Professional diagnostics: In case of difficulty or if you do not have the necessary equipment, it is better to contact a qualified auto mechanic or service center for professional diagnosis and troubleshooting.

Remember that accurate diagnosis requires professional attention and experience, so if you have problems with the P0377 code, it is recommended to contact a specialist.

Diagnostic errors

When diagnosing DTC P0377, the following errors may occur:

• Insufficient detail: The error may be caused by insufficient diagnostic data detail. It is necessary to ensure that all parameters are checked with due care and precision.
• Skipping Basic Steps: Skipping or incorrectly performing basic diagnostic steps, such as checking wiring, connectors, or optical sensor condition, may lead to incorrect conclusions.
• Misinterpretation of data: Incorrect interpretation of data from the sensor or PCM can lead to incorrect diagnosis and the wrong solution.
• Insufficient experience or knowledge: Lack of sufficient experience or knowledge in the field of diagnosing engine control systems can lead to errors in determining the cause of the malfunction.
• Hardware problems: Poor or faulty diagnostic equipment may produce incorrect or unreliable results, affecting diagnostic accuracy.
• Unaccounted factors: Unaccounted for factors, such as environmental conditions or other faults, may lead to incomplete or inaccurate diagnostic conclusions.

To avoid these errors, it is important to follow standard diagnostic procedures, carefully analyze the data obtained and, if necessary, seek help from experienced specialists or use professional equipment.

How serious is the fault code? P0377?

Trouble code P0377 is quite serious because it indicates a problem with the high resolution “B” reference signal of the vehicle's timing system. A timing signal mismatch can affect the proper operation of the fuel injection system and ignition timing, which can lead to various engine performance problems. The following problems may occur with this error:

• Loss of engine power.
• Rough engine operation or shaking when idling.
• Increased fuel consumption.
• Problems with starting the engine.
• Possible damage to the fuel injection system or other engine components due to improper fuel conditions.

If the P0377 code is not detected and corrected, it can lead to more serious engine problems and increase the risk of other problems. Therefore, it is recommended to take measures to diagnose and eliminate this error as soon as possible in order to avoid possible negative consequences for the operation of the vehicle.

What repair will help eliminate the code? P0377?

To resolve DTC P0377, you may need to do the following:

1. Checking and replacing the optical sensor: If the optical sensor is damaged, worn or faulty, it must be replaced. To do this, you must install a new sensor and configure it correctly.
2. Checking and repairing wiring and connectors: Check the condition of the wiring and connectors connecting the optical sensor to the engine control module (PCM). If necessary, replace damaged wires or connectors.
3. Checking and setting the disk sensor: Check the condition of the sensor disk on which the signal is read. Make sure it is in the correct position and is not damaged or obstructed. Adjust it if necessary.
4. Checking and updating PCM softwareNote: Under some circumstances, a PCM software update may be required to correct the problem.
5. Additional repair measures: Depending on the diagnostic results, other repairs may be required, such as replacing or adjusting other fuel injection system components or repairing other electrical or mechanical engine components.

It is important to conduct a thorough diagnosis to determine the source of the problem and then carry out the necessary repair measures. If you do not have the experience or necessary equipment to perform the repair, it is recommended that you contact a qualified auto mechanic or service center to perform the repair work.

P0377 – Brand-specific information

Trouble code P0377 indicates a problem with the vehicle's timing system high resolution reference “B” signal. This error can occur in different brands of cars, some of them:

• Ford / Lincoln / Mercury: Invalid ignition distributor timing signal - too few pulses.
• Chevrolet / GMC / Cadillac: Ignition distributor timing signal – too few pulses.
• Toyota / Lexus: Crankshaft position sensor “B” error – too few pulses.
• Honda/Acura: Ignition timing signal level – too few pulses.
• Nissan/Infiniti: Problem with crankshaft sensor high resolution reference B - too few pulses.
• Volkswagen/Audi: Incorrect ignition distributor timing signal.

This is just a small list of brands that may have a P0377 trouble code. Each vehicle manufacturer may have its own unique interpretation of this error code, so it is recommended that you consult your specific vehicle's owner's manual for more information.