P0339 Code: Crankshaft Position Sensor A Circuit Intermittent
The crank signal drops out for moments at a time. Classic sign: stalls when hot, restarts once it cools.
Stop driving
Treat the car as able to stall at any moment, including at highway speed or mid-turn. Avoid highways, left turns across traffic and long trips until it is fixed. If it stalls, coast to the shoulder: steering and brakes get heavy but still work.
At a glance
Severity: High
- Meaning
- Crankshaft Position Sensor A Circuit Intermittent
- System
- Ignition & Misfire · Powertrain
- Safe to drive?
- With caution
- Typical repair cost
- $0–$600
- DIY difficulty
- Moderate
P0339 means the crank sensor signal was working, disappeared briefly, and came back. The computer counts teeth continuously, and when pulses stop arriving for a moment while the engine is clearly still turning, or reappear out of step, it logs an intermittent fault. Because the signal is fine most of the time, a shop visit often finds nothing: the engine starts, idles and revs normally on the lift. The two usual culprits are a sensor whose internal windings or electronics open up as they get hot, and a wire or terminal that loses contact only when the harness moves or the engine vibrates at a certain speed. Catching the dropout while it happens is the whole diagnostic challenge.
How to read P0339
- P Powertrain
- 0 Generic (SAE)
- 3 Ignition / misfire
- 39 Specific fault
Symptoms
- Engine dies after 20 minutes or more of driving, typically in warm weather or stop-and-go traffic
- No restart for a while, then it starts normally once it has cooled for 15 to 45 minutes
- Tachometer briefly drops to zero while the engine keeps running, or a momentary stumble
- Stall over rough pavement or when the engine rocks during a hard shift
- Check-engine light that sometimes turns itself off after a few good trips
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Crank sensor failing when hot (internal crack or solder joint opening up with heat)
- Terminal fretting or a loose connector lock at the sensor
- Harness chafing that makes brief contact as the engine moves on its mounts
- Loose battery terminal or intermittent main engine ground causing voltage dips
- Metal debris on a magnetic tip that occasionally shorts out the pulse
- Worn engine mounts letting the harness stretch or the sensor rub
- Intermittent engine computer fault
Diagnosis step by step
Read the freeze frame
Note coolant temperature, rpm, vehicle speed and load when P0339 set. A coolant reading above about 190°F with the car stopped in traffic points toward a heat-sensitive sensor. A stall at a random temperature but always on rough roads points toward wiring.
Tools: OBD-II scanner
Record the dropout on a scan tool
Most scan tools can graph or record engine rpm. Drive with it recording until the engine stumbles or stalls. A clean rpm trace that suddenly falls to zero and returns while speed doesn't change is a crank signal dropout; a gradual rpm sag is more likely fuel or ignition.
Tools: OBD-II scanner
Try to reproduce it hot
When the engine has stalled and won't restart, measure the sensor right away before it cools: resistance on a two-wire sensor, or the switching signal on a three-wire Hall sensor while cranking. A reading that is open or flat hot but normal once cooled condemns the sensor. On the bench, warming the sensor gently with a hair dryer can provoke the same failure.
Tools: Multimeter
Wiggle test with the engine running
At idle with the scan tool showing rpm, flex the sensor connector and move the harness along its route, then rock the engine lightly by blipping the throttle in gear with the brakes held firmly. A stumble or rpm dropout at one spot pinpoints the fault.
Tools: OBD-II scanner, Flashlight
Check the battery connections and main grounds
Tighten and clean both battery terminals and the engine-to-body ground. A momentary voltage dip can drop the sensor supply and the computer's input for a split second, which also logs P0339 and sometimes P0562.
Tools: Multimeter, Pliers
Repair or replace, then confirm over several trips
Replace the sensor with an OE-quality part if it failed hot, or repair the terminal or harness. Because the fault is intermittent, confirm the fix by driving through the same conditions that caused stalls before and checking that no pending code returns.
Tools: OBD-II scanner
Where the parts are
- 1Ignition coil
- 2Spark plug
- 3Fuel injector
- 4Camshaft sensor
- 5Crankshaft sensor
- 6Engine computer (ECM)
- 7Intake manifold
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Replace crankshaft position sensor (OE-quality) | Yes | $150–$450 |
| Repair connector terminals or chafed harness | No | $100–$350 |
| Clean and tighten battery terminals and engine grounds | Yes | $0–$120 |
| Replace worn engine mount | No | $200–$600 |
| Diagnostic time to capture an intermittent fault | No | $100–$300 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Notes by brand
Nissan
Early-2000s Nissan models with the QR25DE and VQ35DE engines have a well-documented pattern of crank and cam position sensors that fail when hot, producing exactly the stall-hot, restart-cold behavior described here. Some were covered by a recall, so check the VIN on NHTSA's recall lookup first.
Field data
| Jeep | 6 | Compass, Patriot | |
|---|---|---|---|
| Dodge | 3 | Journey, Grand Caravan | |
| Ford | 3 | Escape |
Source: NHTSA Complaints API (US government open data), analyzed by DTC mention.
Emissions / smog test impact
Will fail
If the check-engine light is on with P0339 when you arrive, the car fails the OBD emissions test. An intermittent code may clear itself after several good trips, but fixing the cause is the only reliable way to pass and to keep the car from stalling.
Frequently asked questions
Why does the engine only stall when it's hot and then restart later?
Inside a failing sensor, a hairline crack in a winding or a solder joint separates as the part expands with heat, breaking the signal. As the engine cools, it closes up again and the signal returns. That repeating pattern is one of the most recognizable sensor failures in cars.
The shop found nothing wrong. What now?
Intermittent faults rarely show up on a cold engine in the service bay. Ask for a test drive with a scan tool recording rpm, or bring the car in right after it has stalled. Measuring the sensor while it is still hot and failing gives the definitive answer.
Is P0339 more dangerous than P0335?
In a way, yes. With P0335 the car often won't start at all, so you are stuck in a driveway. With P0339 it runs normally and then quits without warning, possibly in traffic or on the highway.
Could a loose battery cable cause this?
It can. A terminal that loses contact for a split second over bumps causes a voltage dip that the computer can see as a crank signal interruption. Tightening the battery clamps is free and worth doing first.