P0379: The computer gets no pulses on a second high-resolution engine position signal
Timing reference high resolution signal B no pulses
Severity: Severity not verified — if the car runs badly, have it inspected
The sources define the code and link it to no-start and misfires but do not rate its seriousness, so severity is not verified.
P0379 in short
P0379 means the engine computer sees no pulses on its high-resolution timing reference signal B, which comes from an engine position sensor. TroubleCodes.net links it to hard starting or no-start and lists damaged wiring, a bad crankshaft or camshaft sensor, a damaged reluctor wheel or sensor gap as causes.
The computer times spark and fuel from pulses sent by the crankshaft and camshaft position sensors. P0379 is set when the timing reference signal labelled B has no pulses at all. The Delaware DMV list and TroubleCodes.net give the same meaning.
TroubleCodes.net says the computer detects no signal from an engine position sensor and notes misfires, hard starting or no-start as possible symptoms. Which sensor is signal B depends on the maker, so the vehicle's manual identifies the circuit.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Damaged, corroded or disconnected wiring or connector
Possible — needs testing- Why it ranks here
- TroubleCodes.net lists wiring and connector damage first, and a broken circuit gives no pulses.
- What would change this
- Rises if wiring is damaged or a connector is loose or corroded. Falls if continuity and reference voltage are correct.
Cause 2: Failed crankshaft or camshaft position sensor
Possible — needs testing- Why it ranks here
- TroubleCodes.net names defective crank or cam sensors; a dead sensor sends no pulses.
- What would change this
- Rises if wiring tests good and the sensor output is missing while cranking. Falls if the sensor signal is present.
Cause 3: Damaged or clogged reluctor wheel, or too much sensor gap
Possible — needs testing- Why it ranks here
- TroubleCodes.net lists a clogged or damaged reluctor wheel and an excessive air gap between sensor and wheel.
- What would change this
- Rises if the wheel is damaged or packed with debris, or the gap is out of specification. Falls if both are fine.
Cause 4: Failed engine control module (rare)
Possible — needs testing- Why it ranks here
- TroubleCodes.net calls this rare.
- What would change this
- Rises only if wiring, sensor and reluctor all test good.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Record all stored codes and freeze-frame data with a scan tool, noting any misfire or other position-sensor codes.
IfMisfire or other crank/cam codes are stored too
It meansRecord them for the shop; they point to the same circuit.
IfOnly P0379 is stored
It meansInspect the wiring next.
Step 2: Inspect the wiring and connectors for the crank and cam sensors for visible damage, corrosion or looseness.
IfVisible damage found
It meansRepair it and retest.
Points to: Damaged, corroded or disconnected wiring or connector
IfNothing visible
It meansHave the sensor, air gap and reluctor wheel checked.
Step 3: Have a shop check the sensor air gap and reluctor wheel, then test sensor resistance, reference voltage and output against the manual.
Warning:The sensor sits next to the crank pulley, belts and hot engine parts; the engine must not be cranked while hands or tools are near them. Test with the ignition off first.
IfThe reluctor wheel is damaged or the gap is wrong
It meansClean or correct it.
Points to: Damaged or clogged reluctor wheel, or too much sensor gap
IfSensor output is missing with good wiring
It meansReplace the sensor.
IfEverything tests good and the code returns
It meansSuspect an intermittent fault or, rarely, the computer.
Symptoms
- Check engine light is on
- Hard starting or no start
- Misfires across the rev range
How to fix
Step 1: With the engine off and cool, look at the visible wiring and connectors near the crankshaft and camshaft sensors for damage, oil soaking or a loose plug.
Parts and cost context
- Crankshaft position sensor:Test the circuit and sensor before buying parts. Labour varies; get a quote.
Labor varies by vehicle and shop; get a quote before you approve a repair.
Compare used part prices on PartPriceGuideOn your vehicle
We don't have reviewed vehicle-specific evidence for P0379 yet. The causes and tests above apply across vehicles.
Related codes
No curated relationships for P0379 yet.
P0379 questions
Can I drive with P0379?
Not enough is sourced to rate it, but the sources link it to hard starting, no-start and misfires. If the car stalls or will not start reliably, have it checked before driving.
Sources and review
- TroubleCodes.net P0379: timing reference high resolution signal B no pulses
- On-Board Diagnostic Trouble Codes (generic code title list)
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error