Faulty crankshaft position sensor. Open or shorted wiring to the crank sensor. Corroded or fluid-soaked connector at the sensor (listed by OBD-Codes.com). Broken or damaged tone (reluctor) ring, or metal debris on the sensor tip. Faulty PCM or PCM programming error (less likely).

Repair damaged, oil-soaked or corroded crank sensor wiring or connectors. Replace the crankshaft position sensor (RepairPal lists this as the common repair; OBD-Codes.com notes some manufacturers recommend replacing the crank and cam sensors as a set). Clean metal debris off the sensor tip, or repair a broken or worn reluctor ring. PCM repair, reprogramming or replacement only after everything else checks out.

P0339🔧 Engine timing / cam and crank sensorsStop and fix promptly

P0339: Crankshaft Position Sensor A Circuit Intermittent (Meaning, Causes, Fixes)

Q: What does P0339 mean?

P0339 means the engine computer (PCM) is seeing an intermittent, irregular or missing signal from the crankshaft position (CKP) sensor. The usual causes are a failing crank sensor, damaged or oil-soaked wiring and connectors, or a broken tone (reluctor) ring. Because the fault comes and goes, careful wiring checks matter before replacing parts. The crankshaft position sensor reads the teeth of a toothed ring (the reluctor or tone ring) on the crankshaft, so the PCM knows engine speed and crank position. The PCM uses that signal to time the spark and fuel delivery. RepairPal says P0339 sets when the PCM detects an irregular signal or no signal, and notes the sensor may be built into the distributor on older vehicles. OBD-Codes.com says it sets when the PCM detects an intermittent or erratic voltage signal from the sensor, and elsewhere in the same article that it stores when the input voltage is too low over a set period. The sources disagree on which sensor: RepairPal names sensor "A", while OBD-Codes.com's P0339 article says sensor "B" (a secondary sensor). OBD-Codes.com's own P0385 article is titled Crankshaft Position Sensor B, and both sources list P0335 to P0338 alongside P0339, so on most vehicles P0339 refers to the main (A) crank sensor circuit. Check your vehicle's service information to be sure.

Q: Can I keep driving with P0339?

Stop and fix promptly. Get this diagnosed promptly. RepairPal rates P0339 Urgent, and OBD-Codes.com says a no-start condition will likely come with it, so it could be called severe. Because the signal drops out intermittently, the engine may hesitate, stall or refuse to start without warning. Avoid relying on the car, especially in traffic or on the highway, until it's checked.

Reviewed 2026-10-23 · Based on 3 cited source(s)

What P0339 means

The crankshaft position sensor reads the teeth of a toothed ring (the reluctor or tone ring) on the crankshaft, so the PCM knows engine speed and crank position. The PCM uses that signal to time the spark and fuel delivery. RepairPal says P0339 sets when the PCM detects an irregular signal or no signal, and notes the sensor may be built into the distributor on older vehicles. OBD-Codes.com says it sets when the PCM detects an intermittent or erratic voltage signal from the sensor, and elsewhere in the same article that it stores when the input voltage is too low over a set period. The sources disagree on which sensor: RepairPal names sensor "A", while OBD-Codes.com's P0339 article says sensor "B" (a secondary sensor). OBD-Codes.com's own P0385 article is titled Crankshaft Position Sensor B, and both sources list P0335 to P0338 alongside P0339, so on most vehicles P0339 refers to the main (A) crank sensor circuit. Check your vehicle's service information to be sure.

Severity: can I keep driving?

Stop and fix promptly

Get this diagnosed promptly. RepairPal rates P0339 Urgent, and OBD-Codes.com says a no-start condition will likely come with it, so it could be called severe. Because the signal drops out intermittently, the engine may hesitate, stall or refuse to start without warning. Avoid relying on the car, especially in traffic or on the highway, until it's checked.

Common symptoms

Check engine light on
Engine won't start, or stalls and won't restart
Tachometer doesn't move while cranking (listed by OBD-Codes.com)
Hesitation on acceleration or decreased engine performance
Worse fuel economy

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

Faulty crankshaft position sensor
Open or shorted wiring to the crank sensor
Corroded or fluid-soaked connector at the sensor (listed by OBD-Codes.com)
Broken or damaged tone (reluctor) ring, or metal debris on the sensor tip
Faulty PCM or PCM programming error (less likely)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

Write down the freeze frame data and any other stored codes before clearing anything. OBD-Codes.com notes this helps a lot when the code is intermittent.
Inspect the crank sensor wiring and connector for chafing, breaks and corrosion. OBD-Codes.com says to look carefully for engine oil, coolant or power steering fluid on the wiring, since those can break down the insulation.
Wiggle the harness and connector with the engine running (or while watching RPM on a scan tool) to see if the problem shows up.
If you have a multimeter and a wiring diagram, check for the reference voltage (often 5 V, but check the factory spec) and ground at the sensor connector, and test the sensor's resistance against the factory spec.
Look up technical service bulletins (TSBs) for your vehicle, as OBD-Codes.com suggests.

Typical fixes

Repair damaged, oil-soaked or corroded crank sensor wiring or connectors
Replace the crankshaft position sensor (RepairPal lists this as the common repair; OBD-Codes.com notes some manufacturers recommend replacing the crank and cam sensors as a set)
Clean metal debris off the sensor tip, or repair a broken or worn reluctor ring
PCM repair, reprogramming or replacement only after everything else checks out

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

The engine stalls or won't start
The fault is intermittent and the wiring looks fine; OBD-Codes.com's procedure uses an oscilloscope to watch the sensor waveform for glitches at the sensor and again at the PCM connector
The code comes back after replacing the sensor, which can point to a reluctor ring problem or a wiring fault between the sensor and the PCM

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Can I drive with P0339?

It's risky. RepairPal rates it Urgent, and because the crank signal drops out intermittently the engine can stall or not restart. Get it checked before relying on the car.

Is P0339 sensor A or sensor B?

The sources disagree. RepairPal calls it sensor "A". OBD-Codes.com's P0339 article says sensor "B", but its own P0385 article is the sensor B code and both sources group P0339 with P0335 to P0338. Your vehicle's service information will say which sensor it means.

What's the difference between P0335 and P0339?

P0335 is a general fault in the crank sensor circuit. P0339 is specifically an intermittent or erratic signal, so wiring, connectors and the reluctor ring deserve extra attention.

Should I just replace the crank sensor?

Not before checking the wiring and connector. Both sources list wiring faults, and RepairPal also lists a broken tone ring, which a new sensor won't fix.

Sources

Last reviewed 2026-10-23. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.