P0340
Fix within a few daysThe engine computer isn't getting a proper signal from the camshaft position sensor on Bank 1.
Code P0340 means your engine computer isn't getting a proper signal from the camshaft position sensor. Common causes: Bad camshaft position sensor (70%), wiring issues (20%). Drivability: Limit driving, fix within a few days. Repair cost: $30-$200 DIY, $150-$500 professional.
Can I Drive With P0340?
Limit driving, fix within a few days
Essential trips under 10 miles, avoid highways and heavy acceleration. Be prepared for potential stalling or no-start conditions.
Stop driving immediately if: Engine will not start, engine stalls repeatedly, engine makes loud knocking noises, or the Check Engine Light is flashing.
Symptoms of P0340
- 1Engine cranks but won't start
- 2Engine stalls shortly after starting
- 3Rough idle or poor engine performance
- 4Reduced engine power
- 5Check Engine Light is on
Common Causes of P0340
Parts most likely causing this code, ranked by probability
A faulty camshaft position sensor fails to send the correct timing signal to the engine computer, disrupting engine operation.
70% of P0340 cases are fixed by replacing this part
Damaged, corroded, or loose wiring and connectors prevent the camshaft position sensor signal from reaching the engine computer.
20% of P0340 cases are fixed by repairing wiring or connectors
The engine computer compares camshaft and crankshaft signals, so a bad crankshaft sensor can sometimes cause a P0340 if the signals don't correlate.
5% of P0340 cases are fixed by replacing this part
A rare internal fault within the engine computer can prevent it from properly reading the camshaft position sensor signal.
3% of P0340 cases are fixed by replacing this part
A stretched timing chain/belt or a problem with the variable valve timing system can cause the camshaft position to be out of sync, triggering the sensor code.
2% of P0340 cases are fixed by repairing timing components
Check These First (Before Buying Parts)
- Inspect the camshaft position sensor's electrical connector for looseness, corrosion, or bent pins.
- Visually check the wiring harness leading to the sensor for any signs of damage, fraying, or rodent chew marks.
How to Diagnose P0340
- 1Visually inspect the camshaft position sensor and its wiring harness for any obvious damage, fraying, or loose connections.
- 2Check the sensor connector for corrosion or bent pins.
- 3Using a multimeter, test for proper voltage supply (typically 5V or 12V) and ground at the sensor connector with the ignition on.
- 4If power and ground are present, test the sensor's signal output using a multimeter or oscilloscope while cranking the engine.
- 5If the sensor tests bad or wiring is confirmed good, replace the camshaft position sensor.
- 6If the issue persists, consider checking the crankshaft position sensor and its circuit, as well as inspecting timing components.
P0340 on Popular Vehicles
Honda Accord
2003-2012P0340 is a common issue on these models, often due to a failing camshaft position sensor. The sensor can be located in various spots depending on the engine (e.g., near the cylinder head or timing cover).
75% fixed by replacing the camshaft position sensor
Nissan Altima
2002-2013Nissan vehicles, including the Altima, are known for camshaft and crankshaft position sensor failures. It's important to check both sensors and their wiring, as a bad crankshaft sensor can sometimes trigger cam sensor codes.
70% fixed by replacing the camshaft position sensor
Ford F-150
2004-2010On Ford F-150s with VVT (Variable Valve Timing) engines, P0340 can sometimes be related to VVT system issues or stretched timing chains, in addition to a faulty sensor. Always check for other VVT-related codes.
65% fixed by replacing the camshaft position sensor
Frequently Asked Questions
What does P0340 mean?
P0340 indicates that your vehicle's engine computer has detected an issue with the camshaft position sensor circuit on Bank 1. This sensor tells the computer the exact position of the camshaft, which is crucial for engine timing and fuel injection.
Can I drive with P0340?
Limit driving, fix within a few days. If your engine won't start or stalls frequently, do not drive it. If it starts but runs rough or has reduced power, drive only for essential, short trips and get it repaired quickly to prevent further issues.
Will P0340 clear itself?
No, P0340 will not clear itself. The engine computer stores this code because it detects a persistent fault in the camshaft position sensor circuit. You need to diagnose and fix the underlying problem, then clear the code with a scan tool.
How do I fix P0340 myself?
Start by inspecting the camshaft position sensor's wiring and connector for damage or corrosion. If they look good, test the sensor's electrical signals with a multimeter. If the sensor is faulty, replacing it is often a straightforward DIY job, requiring basic hand tools and sometimes a specific socket.
How much does it cost to fix P0340?
DIY repair costs for P0340 are typically $30-$200, mainly for the camshaft position sensor part. Professional repair costs range from $150-$500, covering parts and labor. Costs can be higher if the issue is with the ECM or timing components.
P0340 keeps coming back - why?
P0340 keeps coming back because the root cause hasn't been fully addressed. This often happens if you replaced the sensor but the actual problem was in the wiring, the connector, or even a related component like the crankshaft position sensor. Always perform thorough diagnostics.
Will P0340 fail emissions/smog test?
Yes, P0340 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on, regardless of the code, is an automatic failure in most states. Furthermore, a faulty camshaft position sensor directly impacts engine timing and emissions control.
What's the difference between P0340 and P0335?
P0340 indicates a problem with the camshaft position sensor circuit, which monitors the camshaft's rotation. P0335 indicates a problem with the crankshaft position sensor circuit, which monitors the crankshaft's rotation. Both are critical for engine timing, but they monitor different components.
P0340 on Honda Accord?
P0340 is a common code on Honda Accords, particularly older models. The camshaft position sensor itself is a frequent failure point. Accessing it can sometimes be tricky depending on the engine, but it's a common repair for these vehicles.
Questions to Ask Your Mechanic
Did you check the voltage supply and ground at the camshaft position sensor connector?
Good answer: Yes, I confirmed 5 volts (or 12 volts, depending on the vehicle) and a good ground at the connector. The circuit itself is solid.
What did the waveform look like from the camshaft position sensor on a scope?
Good answer: The waveform was erratic/flat/missing, confirming the sensor itself is not producing a proper signal. Or, the waveform was good, indicating a wiring issue further down the line or an ECM problem.
Repair Cost Estimate
DIY Repair
Parts only
$30-$200
Shop Repair
Parts + labor
$150-$500
Save $120-$300 by doing it yourself
Difficulty
intermediate
Time
1-3 hours
Intermediate - requires basic hand tools and a multimeter for proper diagnosis. Replacing the sensor itself is often simple, but electrical testing adds complexity.
Cost of Waiting
Ignoring P0340 can lead to your engine not starting at all, leaving you stranded. Continued poor engine timing can also cause misfires, which send unburned fuel into your catalytic converter, potentially destroying it. A $50 sensor job now prevents a $1,200-$2,500 converter replacement later.
While You're In There...
The engine computer relies on both camshaft and crankshaft sensor signals for timing. If the crankshaft sensor is easily accessible during the camshaft sensor replacement, it's a good idea to inspect or replace it, especially if symptoms are severe or intermittent.
Applying dielectric grease to electrical connectors helps prevent corrosion and ensures a good electrical connection, which is crucial for sensor signals.
Tools You'll Need
- Basic socket/wrench set
- Screwdriver set
- Multimeter
- Wire stripper/crimper (if wiring repair is needed)
- OBD-II scan tool (to clear codes)
P0340 is a very common engine code, and in most cases, it's a straightforward fix involving a relatively inexpensive sensor. Once repaired, your engine will run smoothly and reliably again.
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Your Next Steps
Step 1: Perform a thorough visual inspection of the camshaft position sensor and its wiring. Look for any obvious damage, loose connections, or corrosion.
Step 2: If the visual inspection doesn't reveal the issue, use a multimeter to test for proper voltage supply and ground at the sensor connector. Then, test the sensor's signal output.
Step 3: If the sensor tests faulty or the wiring is confirmed good, replace the camshaft position sensor. Clear the code with a scan tool and test drive the vehicle.