#OBD Codes
P0340 – Camshaft position sensor circuit malfunction
Technical definition
Camshaft position sensor circuit
What does P0340 mean?
When you see error code P0340, it means your vehicle has detected a problem with the camshaft position sensor circuit. This sensor, often called the cam sensor, works with the crankshaft position sensor to keep your engine running smoothly and in sync. A malfunction here could cause a cascade of problems, including reduced engine power and jerking.
Read more: What is camshaft?
But don’t rush to replace the sensor just yet – simply replacing the camshaft sensor will not always solve your problems. Sometimes, the issue lies with the wiring or an open circuit rather than the sensor itself.
What does the camshaft position sensor do?
Your camshaft position sensor monitors how fast your engine’s camshaft is spinning and its position. It sends this data to your engine control unit (ECU), which then calculates the perfect fuel injection and ignition timing. If this signal is interrupted, it throws off your engine's timing, leading to rough performance or even misfires.
When this happens, the ECU logs the P0340 code. This might also trigger related codes like P0340-P0344, P0011–P0019, or P0335–P0339, all of which can activate the check engine light.
Camshaft position sensor
How serious is the P0340?
It's important to address it promptly, as what starts as a minor problem can escalate into severe engine damage. The camshaft position sensor is crucial for your engine’s performance and neglecting it could lead to costly repairs.
Pro tip: A diagnostic scanner can help you catch issues like P0340 early and save money by identifying the problem before you visit a mechanic. Learn more about what a code reader is here.
Can I still drive with P0340?
Technically, yes, but it’s not a good idea. A malfunctioning camshaft position sensor can cause rough idling, poor acceleration, and sudden engine jerks while driving. These issues make your car unreliable and unsafe – especially when merging onto highways or navigating heavy traffic.
Sometimes, your car might enter limp mode, a safety feature that limits engine performance to protect it from further damage. While limp mode can help you get to a repair shop, it’s unsuitable for long drives.
Common symptoms of P0340
Watch for these warning signs:
- Check engine light
- Rough idle
- Increased fuel consumption
- Reduced engine power
- Sudden engine jerks
- Difficulties in starting the engine
- Engine stalling
- Limp mode
Common causes of P0340
Code P0340 appears due to:
- Faulty camshaft or crankshaft position sensor
- Wiring issues
- Loose connection
- Worn timing chain/belt or tensioner
- Damaged reluctor wheel for the camshaft position sensor
- Issues with powertrain control module or engine control unit
How to troubleshoot P0340
Use these tips to diagnose and fix a P0340 error code accurately:
Clear the codes and test drive
Firstly, use your scan tool to clear the P0340 fault code from your car.
- If the fault code immediately reappears: This indicates the issue is ongoing. Skip the test drive and continue troubleshooting other potential causes.
- If the codes clear successfully: Drive your car for about 15 minutes to fully warm up the engine and observe its behavior.
After the test drive, perform another scan to see if the code reappears. If it does, this confirms the problem persists and requires further investigation.
Pro tip: During the scan, pay attention to other trouble codes, which may help you identify the culprit. For example, P0014 indicates that an exhaust camshaft timing is off, causing the valves to open too early in the engine cycle.
Inspect camshaft and crankshaft position sensors and wiring
1. Locate the camshaft position sensor. Start by identifying the camshaft position sensor. You’ll typically find it behind the cylinder head, in the lifter valley, or next to the engine block.
2. Perform a visual inspection. Once you’ve found the sensor, visually inspect it, along with all the wiring and connectors. Sometimes, simply pushing loose connectors back into place might fix the P0340 error code.
3. Replace damaged wiring or connectors. If the connectors or wiring are in bad shape, it’s worth replacing them. Old, damaged connectors or worn-out wiring can mess with the circuit.
4. Test the circuit voltage. To make sure everything is working as it should, use a multimeter to test the circuit voltage to confirm solid connections and proper power flow.
Don’t forget about the crank sensor – it’s just as important. Since these two sensors work together, problems with one often mean issues with the other. Inspect the crankshaft sensor and its wiring for similar damage or faults.
After inspecting, repairing, or replacing faulty components, take your vehicle for a drive. Test the acceleration to make sure everything is running smoothly again.
Disclaimer: Advice, how-to guides, and car care tips on our blog are intended as helpful resources for general maintenance and repairs. While we strive for accuracy, the information is provided to the best of our knowledge and should be used at your own discretion and risk.
Always refer to your vehicle's owner's manual or consult a certified mechanic for specific repair details and safety procedures.
Always refer to your vehicle's owner's manual or consult a certified mechanic for specific repair details and safety procedures.
