P0343
Fix within a few daysYour engine's computer detects a high electrical signal from the Camshaft Position Sensor 'A' circuit. This sensor tells the computer the exact position of the camshaft, which is critical for engine timing.
Code P0343 means your engine's camshaft position sensor 'A' circuit has a high electrical signal. Common causes: Faulty camshaft position sensor (70%), wiring issues (25%). Drivability: Limit driving, fix within a few days. Repair cost: $50-$200 DIY, $150-$500 professional.
Can I Drive With P0343?
Limit driving, fix within a few days
Essential trips under 10 miles, avoid highways and situations where an unexpected stall would be dangerous.
Stop driving immediately if: Engine stalls repeatedly, flashing Check Engine Light, significant power loss, or engine makes unusual noises.
Symptoms of P0343
- 1Check Engine Light is on
- 2Engine is hard to start or won't start at all
- 3Engine stalls unexpectedly
- 4Engine runs rough or idles poorly
- 5Reduced engine power or poor acceleration
- 6Engine misfires
Common Causes of P0343
Parts most likely causing this code, ranked by probability
The sensor itself has failed internally, sending an incorrect high voltage signal to the engine computer.
70% of P0343 cases are fixed by replacing this part
Damaged, corroded, or loose wiring or a faulty connector can cause an intermittent or constant high voltage signal.
25% of P0343 cases are fixed by repairing wiring or connector
A rare internal fault within the engine computer can cause it to misinterpret the sensor signal or send an incorrect reference voltage.
5% of P0343 cases are fixed by replacing the ECM/PCM
Check These First (Before Buying Parts)
- Visually inspect the camshaft position sensor's electrical connector for any looseness, corrosion, or damage.
- Examine the wiring harness leading to the sensor for any cuts, fraying, or signs of rodent damage.
How to Diagnose P0343
- 1Visually inspect the camshaft position sensor and its electrical connector for any obvious damage, corrosion, or loose connections.
- 2Check the wiring harness leading to the sensor for frayed wires, shorts, or open circuits.
- 3Using a multimeter, test the voltage supply to the sensor and the signal output. Compare readings to your vehicle's service manual specifications.
- 4If wiring and voltage supply are good, remove and test the camshaft position sensor (if possible) or replace it as the most likely culprit.
- 5If the code persists after sensor replacement and wiring checks, further diagnosis of the ECM/PCM may be necessary by a professional.
P0343 on Popular Vehicles
Honda Accord
2003-2024Camshaft position sensor failures are common. The sensor is usually located on the cylinder head, making it a straightforward replacement. Always inspect the wiring harness for rodent damage.
75% fixed by replacing the sensor
Toyota Camry
2007-2024P0343 on a Camry often points directly to a faulty camshaft position sensor. Access can vary, but it's typically on the front or side of the cylinder head. Check the electrical connector for corrosion.
70% fixed by replacing the sensor
Ford F-150
2004-2024For F-150s, especially with V8 engines, the camshaft position sensor is a frequent cause of P0343. Ensure the sensor's O-ring is properly seated during replacement to prevent oil leaks.
65% fixed by replacing the sensor, 20% by wiring repair
Frequently Asked Questions
What does P0343 mean?
P0343 indicates that your vehicle's engine computer has detected a higher-than-expected voltage signal from the camshaft position sensor 'A' circuit. This sensor is crucial for determining engine timing and fuel injection.
Can I drive with P0343?
Limit driving, fix within a few days. Driving with P0343 can lead to unexpected engine stalling, hard starting, or a complete no-start condition. It's best to address this code promptly to avoid being stranded or causing further issues.
Will P0343 clear itself?
No, P0343 will not clear itself. The engine computer will store this code until the underlying issue is resolved and the system passes its self-tests. You will need to fix the problem and then clear the code with a scan tool.
How do I fix P0343 myself?
Start by inspecting the camshaft position sensor's wiring and connector for damage or corrosion. If they look good, the most common fix is replacing the camshaft position sensor itself. This often involves removing a bolt or two and unplugging the electrical connector.
How much does it cost to fix P0343?
The cost to fix P0343 yourself is typically $50-$200 for a new camshaft position sensor. If you take it to a shop, expect to pay $150-$500, which includes parts and labor.
P0343 keeps coming back - why?
If P0343 keeps returning, it usually means the initial diagnosis missed something. Double-check the wiring harness for hidden damage or intermittent shorts. Less commonly, a faulty Engine Control Module (ECM) could be the cause, or there might be an issue with the sensor's tone ring on the camshaft.
Will P0343 fail emissions/smog test?
Yes, P0343 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on is an automatic failure in most jurisdictions, and a faulty camshaft position sensor directly impacts engine timing and emissions control.
What's the difference between P0343 and P0340?
P0343 specifically indicates a 'high input' signal from the camshaft position sensor circuit, meaning the voltage is too high. P0340 is a more general 'circuit malfunction' code, which could mean no signal, an intermittent signal, or an incorrect signal, but not necessarily a high voltage.
P0343 on Honda Accord?
On many Honda Accord models, the camshaft position sensor is a common failure point. It's often located on the cylinder head, making it relatively accessible for DIY replacement. Always check for oil leaks around the sensor as well, as oil intrusion can damage the sensor.
Questions to Ask Your Mechanic
Did you test the voltage at the camshaft position sensor connector?
Good answer: Yes, I checked the 5-volt reference, ground, and signal wire. The signal wire was showing a constant high voltage even when the engine was cranking, indicating a sensor or wiring issue.
What did you find when you inspected the wiring harness for the camshaft position sensor?
Good answer: I thoroughly checked the harness from the sensor back to the ECM for any signs of fraying, shorts to power, or corrosion. Everything looked intact, so we moved on to testing the sensor itself.
Repair Cost Estimate
DIY Repair
Parts only
$50-$200
Shop Repair
Parts + labor
$150-$500
Save $100-$300 by doing it yourself
Difficulty
intermediate
Time
1-3 hours
Intermediate - requires basic hand tools, a multimeter for diagnosis, and careful attention to electrical connections. Access to the sensor can vary by vehicle.
Cost of Waiting
Ignoring P0343 can lead to your engine stalling unexpectedly, making driving unsafe. It can also cause a no-start condition, leaving you stranded. Continued incorrect timing from a faulty sensor can lead to poor fuel economy and potentially damage other engine components over time.
Tools You'll Need
- OBD-II Scan Tool
- Basic Socket Set
- Screwdrivers
- Multimeter
- Wire Strippers/Crimpers (if wiring repair is needed)
P0343 is a common sensor code. Most repairs involve replacing the camshaft position sensor, which is a straightforward job for many vehicles and will get your engine running smoothly 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, corrosion, or loose connections.
Step 2: If the visual inspection doesn't reveal the issue, use a multimeter to test the voltage supply and signal output from the sensor. Compare your readings to your vehicle's service manual specifications.
Step 3: If wiring and voltage checks are good, replace the camshaft position sensor. This is the most common fix for P0343. You'll likely need a new sensor and possibly a new O-ring or gasket.