P0340 Camshaft Position Sensor 'A' Circuit (Bank 1 or Single Sensor)

Common causes

• Failed camshaft position sensor
• Damaged wiring or connector
• Timing belt or chain problem
• Damaged cam reluctor

Symptoms

• Hard starting or no-start
• Stalling
• Rough running
• Poor fuel economy

Can I drive with it?

Often drivable, but the car may stall or not restart. Get it fixed before a long trip.

Tip: If the engine cranks but won't start and P0335 is also set, look at shared wiring or the timing belt before replacing both sensors.

Which scanner reads it?

Any OBD2 scanner reads it.

Budget tools like the ANCEL AD310 read it; tools with live data and graphing – like the BlueDriver or OBDLink MX+ – help you find the cause. Not sure which fits you? Try the Find My Scanner quiz.

In the data

Of the vehicle complaints owners filed with NHTSA from 2015 to 2025, 40 quote P0340 – most often from Nissan, Ford, Jeep owners. Complaints lean toward serious problems, so treat this as a sign of how often the code turns up in real reports, not how often cars get it.

Both sources are compared on the Trends page.

Related codes

• P0335 Crankshaft Position Sensor 'A' Circuit Malfunction
• P0016 Crankshaft Position – Camshaft Position Correlation (Bank 1 Sensor A)
• P0008 Engine Position System Performance (Bank 1)
• P0010 'A' Camshaft Position Actuator Circuit (Bank 1)
• P0011 'A' Camshaft Position – Timing Over-Advanced or System Performance (Bank 1)
• P0014 'B' Camshaft Position – Timing Over-Advanced or System Performance (Bank 1)

General information to help you understand a code – not a diagnosis. Your car’s service information or a qualified mechanic has the final word. See how we research.