P0377: Timing Reference High Resolution Signal B Too Few Pulses
Do not keep driving
Expect reduced performance. A visual inspection of the sensor tip and reluctor is worth doing first.
What this code means
Too few pulses on the second high-resolution reference, implicating the physical signal source — reluctor damage, debris on the sensor tip, or an air gap that has opened.
Likely causes
Start here
- Damaged reluctor or tone ring · specialist
- Metal debris on the sensor tip · easy
- Incorrect sensor air gap · moderate
- Faulty crankshaft position sensor · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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