OBD-II Code P0349 — What It Means & How to Fix It

What Does This Error Mean?

P0349 means the camshaft position sensor circuit has an intermittent fault. The sensor is working some of the time, but the signal keeps dropping out unpredictably. This is the intermittent version of the camshaft position sensor codes. Your engine may run well for days or weeks, then suddenly stumble, hesitate, or stall. Because this fault comes and goes, it can be tricky to diagnose — but don't wait for a complete failure.

Affected Models

All vehicles 1996+
Common in Honda and Acura high-mileage vehicles
Common in Toyota and Lexus vehicles
Common in GM vehicles with VVT engines
Common in Ford vehicles with EcoBoost and modular engines

Common Causes

Camshaft position sensor failing due to heat — the sensor works when cold but drops out when hot
Intermittent break in the cam sensor signal wire at a flex point in the harness
Loose or corroded connector that loses contact under vibration while driving
Oil contamination in the sensor connector causing intermittent short-circuit conditions
Damaged camshaft reluctor ring with minor tooth irregularities causing occasional signal dropouts

How to Fix It

Track when the fault occurs and record all freeze frame data from your OBD-II scanner. Pay particular attention to engine coolant temperature when P0349 was set. A fault that only appears at 190-210°F (full operating temperature) is a classic sign of a heat-failing sensor.

Some scan tools can log data continuously — using one during a long drive can catch the dropout in real time.
Inspect the cam sensor connector carefully. Unplug it and look for oil contamination, corrosion on the pins, or a connector body that doesn't lock firmly. Clean with electrical contact cleaner and dry completely. Reseat the connector until it clicks and tug to confirm it's locked.

Oil leaking from a worn cam sensor O-ring is a very common cause of intermittent cam codes — the oil gets into the connector and causes sporadic faults.
Check the wiring harness from the sensor toward the ECM. Pay special attention to any areas where the harness flexes due to engine movement on its mounts. Wiggle the harness in different spots with the engine running and watch for any engine stumble that would indicate an intermittent break.

Finding the exact fault location this way is satisfying and saves the cost of component replacement guesswork.
If oil contamination is found around the sensor, replace the sensor O-ring and clean the connector thoroughly. On some vehicles, a worn O-ring allows oil to wick up the wiring harness and migrate into the connector plug over time — simply replacing the sensor without cleaning the connector may not solve the problem.

Cam sensor O-rings are available separately on many vehicles for a few dollars.
If the fault only appears after prolonged driving and no wiring issues are found, replace the camshaft position sensor. Heat-induced intermittent failure is the most common cause of P0349 on high-mileage vehicles. Use an OEM or brand-name aftermarket sensor for durability.

On Toyota, Honda, and GM vehicles especially, brand-name cam sensors last significantly longer than no-name alternatives.

When to Call a Professional

Intermittent cam sensor faults are among the harder problems to catch in a shop setting. If the car is running normally when you bring it in, the fault won't be present. A mechanic who can monitor live cam sensor data during a road test — especially after the engine reaches full operating temperature — has the best chance of confirming the fault. Expect $100-$150 for diagnosis and $100-$250 for replacement.

Frequently Asked Questions

How is P0349 different from P0344?

Both P0344 and P0349 are intermittent camshaft position sensor codes. P0344 covers Bank 1 (the bank with cylinder 1, usually driver's side). P0349 covers a different sensor position — either Bank 2 or an alternate cam sensor depending on manufacturer. The diagnosis and repair process is essentially the same for both. The key difference is which cam sensor is causing the problem.

What happens to the engine when the cam sensor signal drops out?

When the cam signal drops out momentarily, the ECM loses part of its engine position reference. On most vehicles, the ECM can compensate temporarily using only the crankshaft sensor signal. This compensation works well enough to keep the engine running, but fuel injection timing may be slightly off. You'll notice this as a brief hesitation, stumble, or RPM fluctuation. If the dropout is longer, the engine may stall.

Should I replace the cam sensor or wait to see if it gets worse?

Don't wait. Intermittent faults always progress to permanent failures eventually. A cam sensor that fails completely can cause a no-start condition at the most inconvenient time. Since the sensor is not expensive and the labor to replace it is modest, it makes much more sense to replace it proactively when you have the code — before it leaves you stranded.