OBD-II trouble code
P0339: Crankshaft Position Sensor "A" Circuit Intermittent
The crankshaft position signal cuts out momentarily and then returns. Because the crank sensor is the engine's master timing reference, even a brief dropout can cause a sudden stall, a no-start, or a hard-to-reproduce hesitation — treat it as a stranding risk.
Quick facts
- System
- Powertrain
- Category
- Sensors / Timing
- Severity
- High severity
- Drivable
- No — stop driving until repaired
- Repair cost range
- $200 – $400 (crankshaft position sensor replacement)
- DIY difficulty
- Intermediate DIY
Browse every code in P0300–P0394, or start from the full code library.
What does P0339 mean?
The crankshaft position (CKP) sensor reads a toothed reluctor wheel on the crankshaft and tells the powertrain control module (PCM) exactly where the pistons are and how fast the engine is turning. Every ignition event and every injector pulse is scheduled off that signal, and misfire detection depends on it as well. There is no graceful fallback: when the crank signal disappears, the PCM has nothing to time against, and the engine simply stops.
P0339 is the intermittent member of the CKP-A family. P0335 is a general circuit fault — no usable signal at all. P0336 is a range/performance complaint, where the pulse pattern exists but is implausible. P0337 and P0338 cover a signal stuck too low or too high. P0339 says the signal was present and correct, dropped out or went erratic for a moment, and then came back. The PCM captured the event and logged it.
That intermittent character is what makes this code both frustrating and genuinely serious. A static measurement in the shop can look normal because the dropout is not present at that moment. When the dropout happens at speed the engine can quit without warning. Drivers typically describe an engine that dies at a stoplight or on the highway, then restarts fine a few minutes later, or a no-start that resolves itself after the car sits.
Heat is one pattern worth testing. A sensor with a failing element can work cold and drop out once it is hot, then return after a cool-down. There is no published minute count that defines that pattern. Connector and wiring problems produce the same symptom: corroded terminals, a partially seated connector, or insulation chafed against a bracket that only makes or breaks contact under vibration or thermal expansion. Mechanical causes are on the same list as electrical ones. A reluctor wheel with a chipped, worn, or debris-packed tooth glitches at the same point in every revolution, and an air gap that has opened up — from a loose sensor mount, a shifted bracket, or metal debris on the sensor tip — weakens the signal until it drops out under vibration.
Because the consequence of the next dropout is a stall, this code should be treated as do-not-rely-on-the-vehicle. It is not a code to drive on for weeks while you think about it.
Common causes
- A crankshaft position sensor that works cold and drops out once hot — one failure mode to test, not a ranked majority
- Corroded, partially seated, or damaged sensor connector
- Chafed or broken sensor wiring, particularly where the harness passes near the exhaust or a bracket
- Damaged, worn, or debris-packed teeth on the reluctor / tone wheel
- Excessive or inconsistent air gap between the sensor and the reluctor wheel
- Metal debris clinging to the magnetic sensor tip, distorting the waveform
- Loose sensor mounting bolt or a shifted mounting bracket
- Electrical noise from ignition components, a failing alternator, or aftermarket wiring bleeding onto the signal circuit
- Timing chain or belt wear letting the crank-to-cam relationship drift enough to corrupt sync
Symptoms
- Check engine light on, sometimes intermittently
- Sudden stall with no warning, often followed by a normal restart minutes later
- Intermittent no-start — the engine cranks but won't fire, then starts fine after it sits
- Extended cranking before the engine catches
- Random hesitation, stumble, or brief loss of power while driving
- Tachometer needle dropping to zero or flickering while the engine is still running
- Symptoms that appear only when the engine is fully warmed up
- Companion misfire codes logged at the same timestamp as the dropout
Diagnostic steps
- 1.Scan and record all codes and freeze-frame data. Engine temperature and RPM at the moment of the fault tell you whether this is a heat-related dropout or a vibration-related one.
- 2.Graph the engine speed PID on a scan tool during a road test that reproduces the conditions from the freeze frame. A momentary drop to zero RPM with the engine still turning confirms a signal dropout. Have a second person read the tool, or log the data and review it afterward — this is not a graph to watch from the driver's seat.
- 3.Better still, put a scope on the CKP signal wire and capture the waveform while driving or while the engine heat-soaks. A glitch that repeats at the same point in every revolution points at the reluctor wheel rather than the sensor.
- 4.Inspect the sensor connector for corrosion, moisture, spread pins, and full seating. Wiggle-test the connector and harness with the waveform on screen.
- 5.Follow the harness from the sensor to the PCM looking for chafe points, especially near exhaust components and mounting brackets where heat and vibration are worst.
- 6.Remove the sensor and inspect the tip for metal debris and for cracks or heat damage to the body. Clean any debris off a magnetic tip.
- 7.Check the air gap and confirm the sensor mounting bolt is present and torqued to specification, and that the bracket has not shifted.
- 8.Inspect the reluctor wheel where it is visible for chipped, worn, or missing teeth and for packed debris between teeth.
- 9.If the vehicle stalls when hot, a targeted heat-or-cool test can confirm it, carefully. This sensor sits low on the engine near the exhaust and often within reach of the belt and crank pulley, so do as much as possible with the engine off and keep hands, hoses and aerosol cans clear of anything rotating when it has to run. Warm the engine, then apply a heat gun on its lowest setting in short bursts aimed at the sensor body alone — never at fuel lines, wiring, or plastic — or chill the sensor with freeze spray when it misbehaves, keeping the propellant off hot exhaust since most are flammable. A signal that recovers when cooled confirms a heat-sensitive sensor. Do not push the sensor past the temperature the engine itself reaches: a heat gun will cook a good one.
- 10.Replace the crank sensor only after the connector, harness, air gap, and reluctor wheel have been checked — a new sensor in a bad connector fails the same way.
Repair cost
$200 – $400 (crankshaft position sensor replacement)
Crankshaft position sensor replacement, parts plus labor. This $200–$400 range is that sensor replacement. RepairPal's national average for the crankshaft position sensor is about $230–$335, with vehicle examples about $205–$375. Wiring, a connector, a reluctor or tone wheel, and a timing chain or belt are discussed on this page and are not included in this range. Those jobs are quoted from the labor time in the service information.
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DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.