P0340 on a Toyota Corolla
P0340 means camshaft Position Sensor A Circuit Malfunction (Bank 1). On the Corolla, a few causes come up far more than others.
What P0340 usually means on a Corolla
P0340 is a camshaft position sensor circuit fault on the Corolla — the ECU has lost or can't trust the cam signal it uses for timing and sequential injection. On these engines it usually means a failed sensor, damaged wiring, or a connector issue, though contamination on the sensor tip from oil can also fool it. Symptoms range from a hard or no-start to stalling and a rough idle, since the ECU depends on this signal to fire the injectors correctly.
Most common causes on the Corolla
- Failed camshaft position sensor
The Denso cam sensor is the most common cause and a straightforward part on these fours.
- Wiring or connector fault
Chafed harness wires or a corroded connector interrupt the signal on older Corollas.
- Oil-contaminated sensor tip
A leaking cam-seal or oil on the sensor can distort the reading, common on oil-burning 1ZZ-FE cars.
- VVT timing out of range
A badly mis-set VVT phaser can throw the cam signal off enough to flag P0340.
What P0340 costs to fix on a Corolla
The camshaft position sensor is an inexpensive part and easy to reach on the Corolla's transverse four, so this is usually a cheap fix. If the trouble is in the wiring, diagnosis takes longer than the part swap. Inspect the connector and check for oil intrusion before ordering a sensor.
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 Toyota Corolla
Related symptoms
Toyota Corolla 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 Corolla?
Every problem becomes a Case. Tell Redline what your Corolla 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.