OBD-II trouble code
P0344: Camshaft Position Sensor "A" Circuit Intermittent (Bank 1)
The bank 1 camshaft signal is dropping out and recovering. The critical question is whether the sensor is failing to read the camshaft, or reading it correctly while the camshaft itself moves — because one is a $200 part and the other is a timing chain.
Quick facts
- System
- Powertrain
- Category
- Sensors / Timing
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $110 – $450
- DIY difficulty
- Intermediate DIY
Browse every code in P0300–P0394, or start from the full code library.
What does P0344 mean?
The camshaft position sensor answers one question for the controller: where in its rotation is the camshaft right now. That answer only has meaning next to the crankshaft signal, because what the controller actually cares about is the relationship between the two. Crank position alone tells it a piston is at the top of its travel; only the cam signal tells it whether that piston is finishing compression and needs a spark, or finishing exhaust and does not. Sequential injection and coil-on-plug ignition both depend on knowing the difference.
P0344 says that answer keeps going missing and coming back. Not absent, not implausible — intermittent. The engine runs normally, then the signal glitches, then it recovers, and the controller logs the interruption.
The distinction that matters most on this code is one that other cam sensor codes do not force you to make. A cam sensor reads teeth on a wheel attached to the camshaft, and on any engine with variable valve timing that camshaft is deliberately being rotated relative to the crankshaft while you drive. So there are two entirely different ways to produce an unstable cam-to-crank relationship. The sensor may be failing to read a shaft that is exactly where it should be. Or the sensor may be reading perfectly while the shaft genuinely wanders — because a timing chain has stretched, a tensioner has lost pressure, or a cam phaser is not holding position.
The stored code set tells you which. P0344 on its own, with nothing else, points at the sensor and its circuit. P0344 accompanied by a cam-crank correlation or timing-over-advanced code changes the meaning completely: the signal is probably honest and the mechanical timing is the fault. Replacing a sensor in that situation fixes nothing and leaves a chain problem to get worse.
Oil condition deserves a mention for the same reason. Variable valve timing actuators are hydraulic, driven by engine oil through narrow passages, and they behave badly on oil that is old, overdue or the wrong viscosity. A phaser that cannot hold position on degraded oil produces a wandering cam signal from otherwise sound hardware — which is why an oil change is a legitimate diagnostic step here rather than an upsell.
Because the fault is intermittent, static testing is close to useless. The sensor will measure fine on the bench and the wiring will pass a continuity check, because at that moment nothing is wrong. Everything on this code depends on catching it live.
Common causes
- Intermittent open or short in the sensor wiring, typically where the loom flexes or passes a heat source
- Connector terminals spread, corroded or not fully latched, making contact until vibration breaks it
- Sensor failing when hot and recovering as it cools — a classic thermal intermittent
- Stretched timing chain or a weak tensioner allowing the camshaft to wander relative to the crankshaft
- Variable valve timing phaser not holding position, often because engine oil is degraded, low or the wrong viscosity
- Metal debris on the sensor tip or a damaged reluctor wheel corrupting the signal at certain speeds
Symptoms
- Check engine light on, sometimes appearing and clearing over several days
- Occasional extended cranking before the engine catches
- Brief stumble, hesitation or momentary stall that clears by itself
- Intermittent rough running with no consistent pattern
- Reduced power for a few seconds before normal operation resumes
- Timing chain rattle on start-up if the mechanical side is the real cause
Diagnostic steps
- 1.Read all stored codes before touching anything. A cam-crank correlation or timing-over-advanced code alongside this one moves the diagnosis from the sensor to the timing chain and phasers.
- 2.Check engine oil level, condition and viscosity. Variable valve timing actuators are oil-driven, and degraded or incorrect oil produces a genuinely wandering camshaft that no sensor can smooth out.
- 3.Study the freeze frame for engine temperature and load at the moment the code set. A fault that only appears hot points at a thermally sensitive sensor or connector.
- 4.Graph the cam and crank signals together while wiggling the harness and connector with the engine running. An intermittent shows up here and nowhere else — static resistance checks pass because at that instant nothing is wrong.
- 5.Inspect the connector for spread terminals and confirm it is fully latched, then check the loom where it flexes or passes near the exhaust.
- 6.Remove the sensor and inspect the tip for metal debris and the reluctor wheel for damaged or contaminated teeth.
- 7.If the wiring and sensor prove sound and the signal still wanders, verify actual mechanical timing against the manufacturer's procedure before spending anything further.
Repair cost
$110 – $450
Camshaft position sensor replacement typically runs $110 to $450 fitted depending on access. Wiring or connector repair usually lands at $80 to $250. Both of those assume the sensor is the fault — if the cause turns out to be a stretched timing chain or a failing phaser, the repair is an entirely different scale, commonly $900 to $3,000 depending on engine layout. That gap is precisely why the accompanying codes and the oil condition are worth checking before a sensor is ordered.
Estimate your repair
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Open the Repair Cost Estimator with camshaft position sensor replacement preselected. Adjust labor rate and vehicle category to fit your situation.
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.