What Does P0339 Mean?
The ECM has detected an intermittent signal from the crankshaft position sensor A. The CKP signal is cutting in and out or exhibiting brief dropouts rather than a complete failure. The driver may experience intermittent misfires, momentary engine stumble, brief stalling at idle, or occasional no-start conditions that resolve by retrying.
Safety Warning
Avoid driving, especially at highway speeds. Intermittent CKP failures can cause sudden, unexpected engine stalling without warning. This is particularly dangerous during highway driving where sudden loss of power also means loss of power steering and reduced brake assist. Have the vehicle diagnosed promptly.
Common Causes
30%
Loose or corroded CKP sensor electrical connector making and breaking contact with engine vibration
25%
Intermittent break in the CKP sensor wiring harness due to flexing, chafing, or heat damage
20%
CKP sensor loosely mounted and vibrating, causing variable air gap to the reluctor ring
15%
Cracked or delaminating reluctor ring with teeth that flex under heat and load
10%
Failing CKP sensor with temperature-sensitive internal component producing dropouts when hot
Diagnostic Steps
1
Monitor engine RPM on live data for dropouts — an intermittent CKP signal will show momentary RPM drops to zero even though the engine is still running; note conditions (hot/cold, idle/load) when dropouts occur.
2
Perform a thorough wiggle test on the CKP sensor connector and wiring harness while the engine idles, watching live RPM data for any disturbance — this quickly isolates connector or wiring faults.
3
Check the CKP sensor mounting bolt torque and sensor seating — many CKP sensors use an O-ring and can work loose over time, especially if the O-ring is deteriorated.
4
Inspect the CKP sensor connector pins for corrosion, oil contamination, or spread terminals that could cause intermittent contact — clean and apply dielectric grease.
5
If the issue is temperature-related (only occurs when hot), use a heat gun to warm the CKP sensor while monitoring the signal — a sensor that fails when heated has a thermal intermittent fault.
6
Check the harmonic balancer for rubber separation by marking the outer ring and inner hub, then observing relative movement while cranking — a slipped balancer causes inconsistent reluctor ring position.
Estimated Repair Cost
$80 - $450
Parts + labor, varies by vehicle and location
The ECM has detected an intermittent signal from the crankshaft position sensor A. The CKP signal is cutting in and out or exhibiting brief dropouts rather than a complete failure. The driver may experience intermittent misfires, momentary engine stumble, brief stalling at idle, or occasional no-sta...
The most common cause of P0339 (Crankshaft Position Sensor A Circuit Intermittent) is: Loose or corroded CKP sensor electrical connector making and breaking contact with engine vibration
Typical repair costs for P0339 range from $80 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Avoid driving, especially at highway speeds. Intermittent CKP failures can cause sudden, unexpected engine stalling without warning. This is particularly dangerous during highway driving where sudden loss of power also means loss of power steering and reduced brake assist. Have the vehicle diagnosed promptly.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0339 to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition System
Difficulty
Type
Generic (SAE)
Recommended Tools
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