P0340 on a Hyundai Elantra
P0340 means camshaft Position Sensor A Circuit Malfunction (Bank 1). On the Elantra, a few causes come up far more than others.
What P0340 usually means on a Elantra
P0340 on the Elantra means the PCM lost or could not read the camshaft position signal. The usual cause is the camshaft position sensor itself or its wiring and connector, and a failing sensor can cause hard starting, stalling, or an intermittent no-start, often worse when the engine is hot. On these CVVT engines it is also worth confirming the fault is the sensor and not a timing or oil-related issue skewing the cam signal. Checking the connector for oil contamination is a quick early step.
Most common causes on the Elantra
- Failing camshaft position sensor
The most common cause; the sensor drops out intermittently or fails outright, especially when hot.
- Wiring or connector fault
A corroded or oil-contaminated connector interrupts the signal and mimics a bad sensor.
- Oil contamination at the sensor
A leak letting oil reach the sensor or plug can disrupt the reading.
- Timing or CVVT-related issue
Less commonly, a timing-chain or cam-phasing problem shifts the signal enough to set the code.
What P0340 costs to fix on a Elantra
The camshaft position sensor is a modest part and labor is reasonable, typically a couple hundred dollars all in. Wiring repairs cost little beyond time. Confirm the sensor and its connector before replacing anything, since an oil leak at the connector can masquerade as a failed sensor and lead to needless parts.
Year, engine and mileage change the answer. Start a case and Redline weighs these causes against what your car shows, then names the check that would settle it.
Other codes on the Hyundai Elantra
Related symptoms
Hyundai Elantra problems & recalls by year
Based on widely reported patterns for this model; individual causes vary by year, engine and history. Generic P0340 behavior is covered on the main P0340 page. Confirm with a scan tool before buying parts.
P0340 on your Elantra?
Every problem becomes a Case. Tell Redline what your Elantra is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.