With the P0343 code showing up in your scanner, you know you need to figure out what’s wrong before anything else goes bad. The diagnosis and fix may not be as complicated as you are initially thinking.
In this guide, we cover the top causes of the P0343 trouble code and show you what it means. We also look at the symptoms, the average repair costs and discuss how to troubleshoot the problem. There’s also a section showing some common mistakes that are made and we answer a few of your top questions.
In This Article:
Code Definition
P0343 – Camshaft Position Sensor A Circuit High Input (Bank 1)
What Does the P0343 Code Mean?
P0343 indicates that there’s a voltage issue with the camshaft position sensor. This fixed electromagnetic sensor is connected to the rotating camshaft and it records the positioning of the teeth, letting the computer know every piston stroke, so the air-fuel ratio can be adjusted.
The camshaft position creates gaps that change the magnetic field to adjust the voltage from the sensor. With this trouble code present, it indicates that the voltage isn’t in the manufacturer-specified parameters. This code applies only to the Bank 1 sensor.
Most commonly, this code is found on Chevy, Ford, Toyota, Hyundai, Kia and Volkswagen models. However, because it’s a generic trouble code, it can occur on any vehicle.
What Are The Symptoms Of P0343?
If there’s no information coming from the camshaft position sensor, you are probably going to notice some performance issues. The top symptoms include:
- Check Engine Light
- Rough idle
- Surging and bucking
- Misfires
- No start condition
- Drop in fuel economy
There are times when the symptoms disappear temporarily, only to return again when you restart the engine. Additionally, these problems are going to get worse over time. You may find yourself in the middle of stop-and-go traffic when the car decides to surge, which can be dangerous.
What Are The Causes of P0343?
The camshaft position sensor can easily get contaminated by moisture or oil, causing it to malfunction. Here are the most likely causes of the P0343 trouble code.
- Faulty wiring/connection
- Defective camshaft position sensor
- Dying starter motor
- Weak car battery
- Faulty engine computer
How Serious is the P0343 Code?
Medium – Because the camshaft position sensor needs to be running normally for the engine to operate as intended, you can expect some drivability issues with this trouble code. The information coming from this sensor helps to determine how the fuel injection regulates the air-fuel mixture. Without the right data, there’s going to be an imbalance as the computer attempts to compensate.
Even if you don’t notice the symptoms right away, they will probably start soon. Your car could stall, and you could deal with engine surging or notice a rough idle. Either way, it could cause an accident if you are trying to control the vehicle in a congested area.
How Do I Fix the P0343 Code?
After you run through all of the diagnostic steps, you should have a better idea of how to fix it. Here are a few of the most common fixes.
- Repair wiring/connection
- Replace camshaft position sensor
- Replace starter motor
- Replace car battery
- Update/replace engine computer
Common P0343 Diagnosis Mistakes
If you choose to put a new sensor in, don’t skimp and buy the cheapest one you can find. Cheap or used sensors often don’t live up to the same performance and can fail prematurely.
You don’t need to spend that much more to get a decent sensor. If you buy online, read through customer reviews to see what other people think about the sensor.
How to Diagnose the P0343 Trouble Code?
Even if you aren’t a mechanic, you can figure out what’s wrong with the P0343 trouble code. Here are some basic steps we like to follow when working professionally. You can find more steps and further guidance in your car’s service manual.
- Check for other trouble codes. If other DTCs are present, research them with our online trouble code library to see if it offers any additional help.
- Perform a visual inspection of the sensor. If oil is leaking on the sensor, it could be fouled and may need to be replaced. You may be able to clean it off, depending on the situation. However, you shouldn’t clean or change the sensor without first fixing the offending leak.
- Check the battery condition with a multimeter. If it’s old and needs to be replaced, do that first. Otherwise, look at the connections to see if anything is loose. You can fix these connections and clean off battery corrosion for better conductivity.
- Use your multimeter to test the sensor to ensure it’s receiving enough voltage. If not, the sensor should be replaced.
- In some cases, the starter motor can also cause the problems. You can test this part with a multimeter as well to see if it needs to be replaced.
If all else fails or you are struggling with the repair, reach out to a professional mechanic in your area. It’s never worth trying to fix something if you aren’t sure of the proper procedures or you don’t have the right tools.
How Much Does It Cost To Fix Code P0343?
Here are a few of the most popular fixes for this trouble code with the average cost of parts and labor. If you can repair or replace the part yourself, you will spend even less.
- Repair wiring/connection – $50 to $550
- Replace camshaft position sensor – $175 to $375
- Replace starter motor – $550 to $850
- Replace car battery – $125 to $350
- Update/replace engine computer – $250 to $2,500
A Mechanic’s Tips About The P0343 Code
When the P0343 code sets, it may not be the only one to show up. It’s also possible to see these two codes:
- P0340 – Camshaft Position Sensor Circuit Malfunction
- P0341 – Camshaft Position Sensor Circuit Range/Performance
The difference between the three trouble codes is the type of electrical malfunction and how long the issue lasts.
On top of that, remember that oil leaks can cause the camshaft position sensor to fail. If you are struggling with an oil leak, you want to repair it quickly to avoid larger problems, such as this, from occurring.
FAQs
It can be moderately serious. The camshaft position sensor helps the engine determine how much fuel to inject to keep the mixture balanced. When this ratio is off, you are going to notice performance issues ranging from mild to severe. Get the problem fixed because things can go south at any time.
As long as the car is still running, you may be able to drive it, although we don’t recommend it. At any time, the performance issues can make it difficult to continue driving. If you are driving on a congested road, the inability to control the vehicle can lead to an accident, so it’s best to fix it right away.
Sometimes the problem is just a faulty wire or connection. It can also be due to a failing car battery. Otherwise, it could be due to a defective camshaft position sensor or a dying starter motor. At worst, there may be a problem with the engine computer, which can be an expensive repair.
If you aren’t having trouble getting the car started, you may be able to continue driving, but it’s not recommended. Because performance issues are bound to occur, you could be caught off guard trying to keep control of your vehicle. Instead, have the car diagnosed and repair the problem before driving.
The Check Engine Light will come on to alert you to the problem. Beyond that, there are many performance symptoms you may notice. A rough idle can occur, along with surging or bucking. You may also notice a misfiring engine, struggle to get the engine started or see a drop in fuel economy.
Conclusion
You may already recognize that something is wrong as the P0343 trouble code appears and the Check Engine Light comes on. This issue can lead to a lot of performance issues that are tough to ignore. Yet, many of these symptoms are also caused by other issues, which is why a proper diagnosis is needed.
Jump in with your basic tools and figure out what’s going on or take the car to a professional mechanic. Either way, you’ll want to have it fixed so the car runs better and to get the Check Engine Light to go away. With the Check Engine Light on and the drivability concerns, you won’t know if something else fails in the meantime.
Having trouble locating the Crankshaft Position Sensor on a 1993 Oldsmobile Cutlass Supreme with a 3.4 liter engine? I am experiencing issues of no power to the fuel injection harness as well as no spark coming from the spark plug?
HI
I have opel corsa 2005 3 piston engine (Engine starts good but no Ecceleration at all)
max rpm 2000
plzzz need help
Thanks for your advice. Here is my issue.
2002 BMW 540i (M62TU engine). I am not a mechanic but an enthusiast and do all the work on my cars.
Started with a p0011 code, opened up the engine and replaced the timing guides, timing chains, rebuilt VANOS gears. Put it all together and ran great for a week, then bad. Took it apart again and found the bank 1 oil guide seal (intake cam) snapped and were causing oil pressure issues in the VANOS. Replaced bank 1 intake cam (checked by pro machine shop and was good cam), replaced VANOS gear with another rebuilt one, replaced timing trigger wheel. Car runs good, but now it has a constant P0343. Opened it up a third time and rechecked timing and it was perfect. Still getting P0343.
Replaced sensors, swapped sides, etc with OE BMW sensors, no change
Replaced battery, no change
Replaced VANOS solenoids, no change
Pin 1 has continuity, both sides
Pin 2 has 12v, both sides, I know you say it should be 5V but both mine say 12 v. , is BMW different?
Pin 3 has 12v, both sides
Checked pins at DME and visually look good.
Measure frequencies at pin 2 and 3 with the car running and both sides were at approximately 800 Hz with the car at 500 rpm, with the numbers varying from 600-1000Hz, both sides.
Delete code and on the first start there is no code, no matter how long I drive it. At the second start the code appears.
Any other ideas? Thank You!
First, you should replace both bolts to the camshaft sensors to make sure they are not magnetic. Make sure the harness is ok. On the M62TU engine, there is a common problem with the thermostat housing heater is going bad and pushing coolant inside of the wires into the engine control unit. Check the engine control unit connector and make sure that there is no corrosion or coolant inside the connector and the control unit.
Then you have to measure the signals from the camshaft sensors both directly on them, and at the engine control unit connector, to see if you can see any differences in the signal.
Needing the location of camshaft sensor on 2006 vz commodore please.
I came across a 2010 VW Jetta 2.5 with a P0343 and all I get out of the 3 wire harness plug (using a power probe) is, 1) ground, 2) 4.8 volts and 3) nothing. This is unplugged by the way. Plugged up, it shows basically the same except there’s activity at the terminal (3) that had nothing at first, which would lead me to believe there’s some kind of activity going on there.
Charging system tests okay, I cleaned the throttle body assembly, I got 60 psi fuel pressure while running, This code is now “permanent” by the way. This vehicle will not rev over 3k also. I tried an aftermarket cam sensor, used VW brand cam sensors (2) to no avail. Can an “off” timing belt cause all of this? This is a neighbor’s car and I was just trying to help out. I’m no better than somebody that knows nothing when it comes to European cars.
@D.Hill
The P0343 code is a bit tricky yes, the high input can in rare cases, be caused by a faulty timing.
But for most of the times, it’s a faulty circuit either caused by a faulty camshaft sensor, a wiring issue or the engine control unit. You can also get problems if another sensor is faulty and making a short in the circuit.
Sometimes the crankshaft sensor can cause problems with the camshaft sensor also
But in this case, if you have checked the wirings and replaced the sensor to an OEM sensor, and checked the crankshaft sensor I would take a look at the timing.