Trouble codes · P0340

P0340 meaning

Camshaft Position Sensor A Circuit Bank 1 or Single Sensor

The same first verdict Car Assist shows from this code alone, before a diagnosis. The code does not tell the app whether the warning light is flashing.

What this code doesn’t tell you

A code says where the car noticed a problem. It does not prove which part failed, whether the fault is still present, or what repair this car needs. The engine, other codes, freeze frame and live readings matter.

Usual causes, most likely first

The order is a starting point across cars; the exact engine and its readings can change it.

1. Failed camshaft position sensor
2. Damaged wiring or poor connector contact
3. Valve timing or trigger wheel fault

What you can check

Note starting difficulty and recent timing work. With the engine off and cold, look for an obviously loose connector; have the signal and timing checked before buying a sensor.

Words the car uses

Stored codes

Faults the car has confirmed and saved. They help explain a check-engine light, but a code alone does not prove which part needs replacing.

Freeze frame

A snapshot of the engine's readings when a fault was recorded. It helps show the conditions that caused the fault, even if the car now seems fine.

Readiness monitors

The car's own checks of its emissions systems. An unfinished check means the car has not tested that system yet, so a clean code scan may miss a fault.

Timing advance

When the spark fires, or when fuel is injected, in relation to the piston's movement. The computer adjusts timing as you drive, so it needs to be read alongside engine speed and load.

Engine speed (RPM)

How fast the engine turns, in revolutions per minute. It helps compare readings at idle and while the engine is working.

Find out what’s causing yours

Car Assist reads your car through an OBD-II adapter and your iPhone. Its assistant uses the codes, freeze frame and live readings to work through the likely cause with you.

Find out what’s causing yours