P0340 code meaning
Camshaft Position Sensor A Circuit Bank 1 or Single Sensor
Powertrain system Generic code P03xx codes Check engine light
What P0340 means
The camshaft position sensor, almost always a Hall sensor, tells the engine module which stroke cylinder 1 is in – one crank revolution alone is ambiguous – and measures the actual cam phase with variable timing. Sensor A is the intake camshaft, bank 1 the side with cylinder 1. P0340 means no or too few cam pulses arrive while the crankshaft turns in sync. GM sets it after 5.5 s (or 4 s) of cranking without a cam pulse or fewer than 4 pulses in 3 s running, gasoline engines after two trips. Ford checks the ratio of cam to crank events from 200 rpm. The engine usually keeps running but starts longer and loses power as cam timing is held. Bulletins: corroded connectors on GM V8s (PIP5335C), moisture in the oil on short trips in Ford hybrids (SSM 48598).
P0340 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of P0340
- Check engine light on
- Longer cranking before the engine starts
- Loss of power (cam timing held in its base position)
- Rough idle, occasionally stalling
Common causes of P0340
- Most likelyCamshaft position sensor faulty (heat, moisture)
- Most likelyConnector or wiring corroded or open, 5 V reference disturbed
- PossibleTone wheel on the camshaft or phaser damaged, loose or at the wrong distance
- PossibleTiming drive jumped or wrongly assembled
- Less likelyMoisture in the engine oil from short trips (Ford hybrids)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Camshaft position sensorCamshaft tone wheelSensor wiringEngine control moduleTiming chain
What each part of P0340 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 3 | Area: ignition system or misfire. |
| 40 | The exact fault in that area. |
What to do next
- Note P0340 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0340
What does P0340 mean?
P0340 means "Camshaft Position Sensor A Circuit Bank 1 or Single Sensor". The camshaft position sensor, almost always a Hall sensor, tells the engine module which stroke cylinder 1 is in – one crank revolution alone is ambiguous – and measures the actual cam phase with variable timing. It is a generic code, so it means the same on every make.
Is it safe to drive with P0340?
Drive gently and only to a workshop. With P0340 the car can go into limp mode (reduced power) to protect itself.
Will P0340 fail an emissions test?
Yes, it can. P0340 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0340 to fix?
Difficulty: easy. A typical repair takes 0.3 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0340 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.