Camshaft Position Sensor A Circuit Bank 1 or Single Sensor
What it means
P0340 means the engine control module lost or couldn't make sense of the signal from the camshaft position sensor. That sensor tells the ECM where the camshaft is so it can time fuel injection and spark; without a reliable signal the engine can be hard to start, stall, or refuse to start at all.
Can I keep driving? Risky — a lost camshaft signal can cause hard starting, stalling, or a no-start, so drive as little as possible and be ready for it to quit.
Real-world scan data
Appears alongside · share of P0340 scans
Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.
Common symptoms
What you'll notice
- Check-engine light on
- Hard starting, long cranking, or intermittent no-start
- Stalling or cutting out while driving
- Misfire, hesitation, or reduced power
Common causes
Most likely first
- Failed camshaft position sensor (the most common cause)Likely
- Damaged wiring or a poor/corroded connector at the sensorCommon
- Metal debris or oil contamination on the sensor tipCommon
- Damaged reluctor/tone ring or timing chain issue affecting the signalLess often
- Failed engine control module (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check the camshaft sensor connector for oil, corrosion, or looseness.
- Inspect the sensor wiring for chafing or breaks back to the ECM.
- Test the sensor signal (and its power/ground) with the engine cranking; replace the sensor if it drops out.
- If the signal is erratic, inspect the reluctor ring and verify timing components.
- Clear the code and confirm the car starts and runs without the fault returning.
P0340 by make
Based on commonly reported failure patterns across owner and repair communities, not on our scan data.
Chevrolet
On Chevrolet trucks and cars, the camshaft sensor and its connector are a common cause of hard starting. Check wiring first.
Dodge
On Chrysler-built vehicles such as Dodge models, cam position sensors on 3.7L and 4.7L engines are a commonly reported failure. Check wiring first.
Ford
Commonly reported on Ford V8 trucks such as those with the 4.6L and 5.4L, where a cam sensor or its connector causes hard starting or poor idle. Check the connector and wiring first.
GMC
On GMC trucks and SUVs, the camshaft sensor and its connector are a common cause of hard starting. Check wiring first.
Jeep
On Jeeps, cam position sensors are a commonly reported failure and can cause hard starting. Check wiring first.
Nissan
On Nissans, cam position sensors are a commonly reported cause of hard starting or stalling, particularly on V6 models. Check the connector and wiring first.
FAQ
Quick answers
Is it safe to drive with P0340?+
Can I just clear P0340?+
Related codes
Read more about this code
Read & clear P0340 yourself
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