Timing Reference High Resolution Signal "B" No Pulses
The P0379 code means the vehicle's onboard diagnostic system has detected: Timing Reference High Resolution Signal "B" No Pulses. This is a critical severity code.
- Keep driving?
- No — stop driving
- DIY difficulty
- hard
- Estimated cost
- $200 - $2,000 (parts and labor)
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What Are the Symptoms of P0379?
- Check Engine Light on
- Possible no-start
- Stalling
- Reduced power if the computer falls back to its other position signal
What Causes P0379? (Most Likely First)
- Failed sensor that produces the high-resolution signal High
- Open circuit: broken wire or unplugged connector High
- Lost power or ground feed to the sensor Moderate
- Engine computer fault Low
Can I Still Drive with P0379?
No — stop driving. P0379 is rated critical severity. Continuing to drive in this state risks further damage — get it looked at before your next trip.
Frequently Asked Questions
What does P0379 mean?
P0379 means Timing Reference High Resolution Signal "B" No Pulses: the engine computer is seeing no pulses at all on this signal while the engine is turning.
What is a high-resolution timing reference?
Some engine computers track engine position with two signals: a low-resolution reference for basic timing and a high-resolution signal with many more pulses per revolution for precise spark and fuel timing. Which sensor produces the high-resolution signal depends on the engine.
Is it safe to drive with P0379?
Have it diagnosed before relying on the vehicle. A fault in an engine position signal can cause stalling or a no-start, sometimes without warning.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P0379?
-
Note any other stored codes. Crankshaft or camshaft position codes alongside this one often share the same wiring or sensor fault.
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Look up which sensor supplies high-resolution signal "B" on your engine. It differs by manufacturer, so the service information is the reliable source.
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Inspect that sensor's wiring and connector for chafing, corrosion, moisture or a loose pin.
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With a scope, compare the high-resolution signal against the low-resolution reference while the engine runs or cranks.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
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