OBD codes / P0340 / Toyota Corolla
P0340 on a Toyota Corolla
Camshaft Position Sensor A Circuit Malfunction (Bank 1)
1.8L 1ZZ-FE, 2ZR-FE/2ZR-FAE, and 2.0L M20A-FKS fours.
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 likely causes on this model
- 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 it costs 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. Get a diagnosis for your Corolla — it weighs these causes against your exact configuration and real complaint data.
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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.