P0377 – OBD-II DTC

OBD-II DTC P0377 – Timing Reference High Resolution Signal B Too Many Pulses

DTC P0377 meaning

DTC P0377 refers to a diagnostic trouble code indicating that the engine control module (ECM) has detected an issue with the timing reference high-resolution signal B. Specifically, it indicates that there are too many pulses being received from the sensor responsible for providing this signal. This can lead to incorrect timing information being processed by the ECM, which is critical for engine performance and efficiency.

DTC P0377 symptoms

Common symptoms associated with DTC P0377 may include:

• Check Engine Light illuminated
• Engine misfires or runs rough
• Decreased engine performance
• Increased fuel consumption
• Difficulty starting the engine

DTC P0377 causes

Several potential causes for DTC P0377 include:

• Faulty timing reference sensor
• Wiring issues or damaged connectors
• Faulty ECM or software issues
• Timing belt or chain problems
• Mechanical issues within the engine

DTC P0377 seriousness

DTC P0377 is considered a serious issue as it can affect engine performance and efficiency. If left unaddressed, it may lead to further engine damage or increased emissions. It is advisable to diagnose and repair the issue promptly to avoid potential complications.

How to diagnose DTC P0377

To diagnose DTC P0377, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the code.
2. Check for any additional trouble codes that may provide more context.
3. Inspect the timing reference sensor and its wiring for damage or disconnection.
4. Test the sensor’s output using a multimeter to ensure it is functioning correctly.
5. Examine the ECM for any software updates or faults.
6. Check the timing belt or chain for proper alignment and condition.

How to fix DTC P0377 step-by-step instructions

To fix DTC P0377, follow these step-by-step instructions:

1. Repair or replace any damaged wiring or connectors related to the timing reference sensor.
2. If the timing reference sensor is faulty, replace it with a new one.
3. Ensure the timing belt or chain is properly aligned and in good condition replace if necessary.
4. Update the ECM software if applicable.
5. Clear the DTC using an OBD-II scanner.
6. Test drive the vehicle to ensure the issue is resolved and the code does not return.

Recommended tools for OBD-II diagnostics

Explore our expert picks: The Best OBD2 Scanners for 2025

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

Some of the links on this page may be affiliate links, which means we may earn a small commission if you make a purchase. This helps us keep our DTC database up to date and provide valuable content for free. We only recommend products that we have tested and believe to be the best in their class.