Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
Your car's computer isn't getting enough signals from a part that helps it know when to fire the engine's spark plugs. It's like trying to clap your hands to a song but missing some beats.
The engine control module (ECM) is not receiving the expected number of pulses from the high-resolution timing reference signal B, which is used to determine the precise timing for engine operations.
The P0377 code indicates that the ECM has detected an insufficient number of pulses from the timing reference high-resolution signal B. This signal is crucial for the ECM to accurately control the ignition and fuel injection timing. A lack of pulses can lead to improper engine timing, affecting performance and efficiency.
• Check Engine Light illuminated
• Poor engine performance
• Engine misfires
• Faulty crankshaft position sensor
• Damaged or corroded wiring or connectors
• ECM malfunction
ECM: Engine Control Module
OBD-II: On-Board Diagnostics, a standardized system in vehicles for self-diagnostics and reporting
• Use an OBD-II scanner to confirm the code.
• Inspect the crankshaft position sensor and its wiring.
• Test the ECM for proper operation.
• Replace the crankshaft position sensor if faulty.
• Repair or replace damaged wiring or connectors.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Wrench set
$150 - $500
Moderate
• Chevrolet Silverado
• GMC Sierra
• Pontiac Grand Prix
• Regularly inspect and maintain engine sensors.
• Ensure connectors and wiring are free from corrosion.
• Perform routine engine diagnostics.
Sensor Issue
• Avoid driving long distances until the issue is fixed.
• Have your vehicle inspected by a professional mechanic.
Check with your vehicle manufacturer for specific warranty coverage on engine sensors.
This code has been associated with sensor failures in older vehicles, particularly those with high mileage.
Moderate – It should be addressed soon to avoid engine performance issues.
Ignoring this code can lead to increased emissions and potential engine damage.
• Engine at operating temperature
• Vehicle stationary
The crankshaft position sensor is typically located near the bottom of the engine block, close to the crankshaft pulley.
Q: Can I drive my car with a P0377 code?
A: It's not recommended to drive long distances, as it can lead to engine performance issues.
Q: How do I reset the check engine light after fixing the issue?
A: You can use an OBD-II scanner to clear the code, or disconnect the battery for a few minutes.
High-End · Full-system diagnostics
A full-system bidirectional platform aimed at advanced DIY users and professional diagnostic workflows.
Network faults often require full-system access instead of a generic code reader alone.
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Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
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Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
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Fitment Required · Vehicle-fitment part
Commonly relevant for misfire, ignition-efficiency, and some drivability-related repairs.
Misfire and ignition-related faults commonly involve spark plugs as part of the repair path.
Check the correct plug type, gap, and engine application for your vehicle.
View options on Amazon
Fitment Required · Vehicle-fitment part
Relevant when the fault points toward ignition-coil performance or cylinder-specific ignition issues.
Some ignition faults involve coil performance or cylinder-specific coil problems.
Match the coil to your engine and confirm the failed component before ordering.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.