OBD-II Code P0339 — What It Means & How to Fix It

What Does This Error Mean?

P0339 means the crankshaft position sensor circuit has an intermittent fault. The sensor is connected and generating a signal, but that signal keeps dropping out randomly. This is different from P0337 or P0338 — those are consistent faults. With P0339, the car may run fine for hours and then suddenly stumble, stall, or fail to restart. Intermittent crankshaft position sensor faults are among the most frustrating codes to diagnose.

Affected Models

All vehicles 1996+
Common in GM vehicles (Chevrolet, Buick, Pontiac, Cadillac)
Common in Ford and Lincoln vehicles
Common in Honda and Acura vehicles
Common in Toyota and Lexus vehicles

Common Causes

Crankshaft position sensor that fails under heat — works cold but drops out when hot
Intermittent break in the CKP sensor wiring — a wire that opens and closes under vibration or heat
Loose or partially corroded sensor connector that makes poor contact while driving
Damaged reluctor ring with one or two missing teeth causing brief periodic dropouts
Sensor mounting that is slightly loose, allowing the air gap to change under load

How to Fix It

Gather as much information as possible about when the fault occurs. Does the engine stall at operating temperature but not when cold? Does it happen at idle, or at highway speed? Does it happen every day or randomly? The more detail you can provide, the faster the diagnosis.

Check freeze frame data from the scanner — it captures the exact conditions when P0339 last set.
Inspect the crankshaft position sensor connector. Unplug it and examine the pins closely for any corrosion or slight bending. Reconnect it firmly and ensure the locking tab clicks. Sometimes a connector that isn't fully locked will disconnect under vibration at highway speed.

A new connector pigtail is inexpensive and may fix an intermittent connection problem permanently.
Inspect the sensor wiring harness from the sensor to the ECM. Look for any areas where the wire moves or flexes during engine movement. Wiggle the harness with the engine running and watch for any reaction from the engine. An intermittent break will reveal itself if you find the right spot.

Engine mounts can allow significant engine movement — wiring near the mounts gets flexed constantly.
Check the reluctor ring for damage. Use a flashlight to inspect the toothed ring as it's visible through the bottom of the engine. Look for missing, chipped, or bent teeth. Even one damaged tooth causes a brief signal dropout each revolution that the ECM can detect as an intermittent fault.

Damaged reluctor rings are rare but not unheard of — they can be damaged by debris or road impacts.
If the fault only appears after the engine reaches full operating temperature, replace the crankshaft position sensor. Heat-induced failures are common in older sensors. Use an OEM or high-quality brand sensor — this is not the place to save $10 on a cheap part.

On GM vehicles especially, using a Delphi or ACDelco sensor is strongly recommended over generic aftermarket alternatives.

When to Call a Professional

Intermittent crankshaft position sensor faults are notoriously difficult to catch. The car may run perfectly at the shop — the fault only appears under specific conditions. A mechanic who can connect a recording scan tool and drive the vehicle until the symptom occurs has the best chance of catching it. Given the critical nature of this sensor, don't wait for a complete failure — that usually happens at the worst possible moment. Expect $150-$300 for sensor replacement, more if wiring repair is needed.

Frequently Asked Questions

Why does the crankshaft position sensor often fail when hot?

The sensor sits close to the engine block, which gets very hot during operation. Heat causes materials to expand and contract over thousands of heat cycles. This thermal stress can cause micro-cracks in the sensor's internal coil wire or in the wiring insulation. When cold, everything contracts and makes contact. When hot, things expand just enough to open the circuit. This is why the sensor seems to 'work fine' when the engine is cold.

Can I get stranded from P0339?

Yes — this is one of the codes that can leave you stranded without warning. The engine may run fine for weeks, then suddenly stall at an intersection or refuse to restart after a short stop. Because the crankshaft position sensor is so critical, a complete failure means the engine won't start at all. If you're getting P0339, prioritize replacing the sensor before it fails completely.

Does replacing the crankshaft position sensor require any relearning or reset?

On some vehicles — particularly older GM models — the ECM needs a crankshaft variation learn procedure after replacing the sensor. This procedure is done with a scan tool and takes about 10-15 minutes. Your mechanic should perform this automatically. If the learn procedure is skipped, you may get poor idle quality or even a P0315 code.