Is it safe to drive with this code?

Driving with P0377 is generally not advisable, as the engine may stall unexpectedly, run poorly, or hesitate during acceleration, which can create hazardous situations—particularly in traffic or at higher speeds. Severity can range from moderate to severe depending on symptoms. For full guidance on when repair becomes urgent, please refer to our site disclaimer.

This code may affect your MOT test if the Malfunction Indicator Lamp is illuminated at the time of testing, though the outcome depends on the specific circumstances and tester assessment. For detailed MOT guidance, please see our disclaimer section.

Roughly how much does it cost to fix?

Repair costs typically fall in the low-to-mid three-figure range for most vehicles. Simple sensor replacement with straightforward access is often at the lower end, whilst more complex diagnostics, wiring repairs, or difficult sensor locations can push costs higher. Prices vary considerably between independent garages and main dealers, and will depend on your vehicle make and model.

Can I just replace the sensor without further diagnosis?

Whilst a faulty sensor is a common cause, replacing it without proper diagnosis may not resolve the issue—wiring faults, contamination, timing problems, or reluctor wheel damage can all trigger this code. Thorough testing can prevent unnecessary parts replacement and additional expense.

Professional mechanic working in workshop

← All fault codes | Timing

P0377

Powertrain

Timing Reference High Resolution Signal B Too Few Pulses

The engine control module has detected that the high-resolution timing reference signal from engine position sensor 'B' is showing fewer pulses than expected, which may affect ignition timing and fuel delivery.

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ⓘ Information only. This page provides general educational information about fault code P0377. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.

Recommended next steps

Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.

What does P0377 mean?

P0377 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Timing Reference High Resolution Signal B Too Few Pulses.

This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.

About Timing codes

Timing codes relate to the variable valve timing (VVT) system, cam position, crank position, or the correlation between them. On engines prone to timing chain stretch (BMW N47, Ford EcoBoost, VAG TFSI), these codes often signal a stretched chain rather than a sensor fault.

P0377 is one of 160 codes in this category. Browse all Timing codes →

What we know about P0377 specifically

We record the SAE J2012 standardised definition and the system this code belongs to, but we have not yet published detailed driver-reported symptoms, common causes, or step-by-step diagnostic guidance for P0377.

Rather than invent that information by generating generic content from a template, we leave it out. For specific guidance, the most reliable sources are:

•your vehicle's own service manual or manufacturer-specific technical bulletins
•a qualified mechanic with a manufacturer-level diagnostic tool
•a marque specialist familiar with your make and model

Codes nearby

Codes adjacent to P0377 in the P-code series. Many fault codes appear together with their neighbours because they relate to the same circuit or component.

P0374 Timing Reference High Resolution Signal A No Pulses

P0375 Timing Reference High Resolution Signal B Malfunction

P0376 Timing Reference High Resolution Signal B Too Many Pulses

P0378 Timing Reference High Resolution Signal B Intermittent/Erratic Pulses

P0379 Timing Reference High Resolution Signal B No Pulses

P037D Glow Plug Sense Circuit

Other Timing codes

Other fault codes in the same system as P0377. The ones with detailed guides have plain-English explanations, symptoms, causes, and diagnostic steps.

P0010

"A" Camshaft Position Actuator Circuit (Bank 1) Detailed guide

P0011

"A" Camshaft Position - Timing Over-Advanced or System Performance (Bank 1) Detailed guide

P0012

"A" Camshaft Position - Timing Over-Retarded (Bank 1) Detailed guide

P0014

"B" Camshaft Position - Timing Over-Advanced or System Performance (Bank 1) Detailed guide

P0016

Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor A) Detailed guide

P0017

Crankshaft Position - Camshaft Position Correlation (Bank 1 Sensor B) Detailed guide

Spotted an issue or have something to add? Mechanics, technicians, and drivers who have first-hand experience with P0377 can submit a correction or expansion. We review every submission before publishing, mechanic submissions are prioritised.

Information only, not professional advice

The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →

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