OBD codes / P0340
P0340
SeriousCamshaft Position Sensor A Circuit Malfunction (Bank 1)
Treat P0340 with some urgency. It often causes hard starting or stalling and can progress to a no-start. Driving carefully to a shop is usually fine, but don't ignore it — and if it stems from a timing-chain problem, continued driving risks engine damage.
What this code means
The camshaft position sensor tells the computer where the valves are in their cycle, which it uses (together with the crank sensor) to time fuel injection and spark precisely. P0340 means that camshaft signal is missing or erratic. Usually it's a failed sensor or a wiring/connector fault, but it can also reflect a real timing problem — a jumped or stretched timing chain/belt. A bad cam signal can cause hard starting, stalling, or a no-start, so it's worth sorting out promptly.
Symptoms you might notice
- Hard starting or extended cranking
- Stalling or rough running
- Hesitation and reduced power
- Occasional no-start
- Check-engine light
What it costs to fix
Typical range: $120–$500 · about ~0.3–2.5 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Camshaft position sensor | $30–$200 | ~0.3–2 hrs |
| Wiring / connector repair | $10–$120 | ~0.5–1.5 hrs |
The sensor is usually a low-hundreds job; labor depends on access. A genuine timing-chain or belt problem is a major repair that varies far too much to quote — get it diagnosed if the sensor and wiring check out.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0340 for my exact vehicle →
Frequently asked
Can I drive with P0340?
Short trips to get it diagnosed are usually okay, but it can cause stalling or a no-start, so don't rely on the car for important journeys. If the cause turns out to be timing-related, stop driving and have it checked.
Will P0340 cause a no-start?
It can. Many engines can still start using the crank sensor alone, but a missing cam signal often causes hard starting, long cranking, or stalling — and on some engines, a no-start.
Is P0340 the sensor or the timing chain?
Most often it's the sensor or its wiring, which is the cheaper fix. But it can also flag a jumped/stretched timing chain or belt — a serious repair — so it's worth confirming before assuming it's just a sensor.
How much does it cost to fix P0340?
The sensor is typically a low-hundreds repair depending on access. A timing-chain or belt repair is a major job and much more expensive, which is why diagnosis matters before buying parts.
Seeing P0340 on your car? Get a diagnosis specific to your exact year, make and model.
Diagnose P0340 for my vehicleGeneric OBD-II reference. Manufacturer-specific behavior varies — confirm with a scan tool and, for safety-related codes, a professional inspection.