P0370 critical

Timing Reference High Resolution Signal A Too Many Pulses

The P0370 code means the vehicle's onboard diagnostic system has detected: Timing Reference High Resolution Signal A Too Many Pulses. This is a critical severity code.

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Keep driving?
No -- stop driving
DIY difficulty
hard
Estimated cost
$100 - $600 (parts and labor)
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Common Symptoms

  • Check Engine Light on
  • Erratic engine operation
  • Engine stalls unexpectedly
  • RPM gauge jumps erratically

Probable Causes (Ranked by Likelihood)

  • Electromagnetic interference on crank sensor circuit Very High
  • Damaged reluctor wheel with debris causing extra pulses High
  • Faulty crankshaft position sensor Moderate
  • Loose crank sensor allowing vibration-induced false signals Low

Step-by-Step Diagnostic Procedure

  1. Check crank sensor mounting bolts for tightness.

  2. Inspect reluctor wheel for metallic debris stuck to the teeth.

  3. Check sensor wiring for routing near high-current wires that could cause EMI.

  4. View crank sensor waveform with oscilloscope. Look for extra pulses or noise.

Frequently Asked Questions

What causes too many pulses?

Extra pulses usually come from metallic debris on the reluctor wheel, a loose sensor vibrating, or electrical interference on the sensor wiring.

Can metal shavings cause P0370?

Yes, metal particles from engine wear can stick to the magnetic reluctor wheel teeth, creating extra signal pulses.

How do I check the reluctor wheel?

On some engines you can inspect it by removing the crank sensor and looking through the hole with a flashlight and inspection mirror.

Sources

This page is built from documented references. Verify against your own service info before repair work.

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