Timing Reference High Resolution Signal B Too Many Pulses
The P0374 code means the vehicle's onboard diagnostic system has detected: Timing Reference High Resolution Signal B Too Many Pulses. This is a critical severity code.
- 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 performance
- Possible stalling
- Ignition timing errors
Probable Causes (Ranked by Likelihood)
- Metallic debris on camshaft reluctor Very High
- Faulty cam position sensor B High
- EMI on sensor wiring Moderate
- Loose sensor mounting Low
Step-by-Step Diagnostic Procedure
-
Inspect camshaft reluctor for debris.
-
Check sensor mounting torque.
-
Review wiring routing for EMI sources.
-
View sensor waveform on oscilloscope.
Frequently Asked Questions
What causes extra camshaft sensor pulses?
Usually metallic debris stuck to the sensor or reluctor, a loose sensor vibrating and creating noise, or electrical interference on the signal wire.
How do I clean the reluctor wheel?
Remove the sensor and carefully clean the reluctor teeth with a rag. Use a magnet to remove metal particles. Avoid damaging the teeth.
Can P0374 cause timing to be wrong?
Yes, extra pulses can confuse the PCM about camshaft position, leading to incorrect ignition and fuel injection timing.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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