OBD-II Generic Error Code P0377: How to Fix Timing Reference High Resolution B Too Few Pulses

Medium 1-2 hours Medium Severity Verified June 2026
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Error Code
P0377
Brand
OBD-II Generic
Product Type
automotive
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
1-2 hours
Error code P0377 indicates that the engine control module (ECM) has detected too few pulses from the high resolution timing reference B sensor. This sensor provides precise crankshaft or camshaft position data. The issue is usually a faulty sensor, wiring problem, or damaged reluctor ring.
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Tools You'll Need

How to Fix Error Code P0377

  1. Scan and Verify the Code

  2. Visually Inspect Sensor and Wiring

    Disconnect the battery before working on electrical components.

  3. Test Sensor Voltage and Signal

    Be careful of moving engine parts when cranking.

  4. Inspect the Reluctor Ring

  5. Replace the Sensor if Faulty

Parts You May Need

Timing reference B sensor
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Timing reference B sensor
Check Price on Amazon
Timing reference B sensor
Check Price on Amazon
Timing reference B sensor
Check Price on Amazon
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When to Call a Professional

If you have limited mechanical experience or the code persists after replacing the sensor and checking wiring, consult a professional mechanic. They can perform advanced diagnostics like oscilloscope testing and internal engine checks.

Frequently Asked Questions

Can I drive with error code P0377?
It is not recommended. The engine may run poorly, stall, or fail to start. It can also cause damage to the catalytic converter over time.
What does timing reference high resolution B mean?
It refers to a sensor that provides precise position data of the crankshaft or camshaft, used by the ECM to control ignition timing and fuel injection.
Will clearing the code fix P0377?
Clearing the code may temporarily turn off the check engine light, but the issue will return unless the underlying problem (faulty sensor, wiring, or reluctor ring) is fixed.
What tools do I need to diagnose P0377?
An OBD-II scanner, multimeter, and possibly an oscilloscope. Basic hand tools are needed for sensor replacement.
How much does it cost to fix P0377?
DIY cost is $50-$150 for a replacement sensor. Professional repair ranges from $150-$400 including diagnosis and labor.

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