Wondering what “Camshaft Position Sensor Bank 1” means? We’re guessing you have a P0017 trouble code in your car. This is just one of many trouble codes that indicates that you have a camshaft position sensor issue.
A camshaft position sensor—or CMP for short—trouble code is not to be taken lightly. It’s crucial for your engine’s smooth operation and can lead to severe damage if ignored. Here’s everything you need to know:
What’s A Camshaft?
If you’re unfamiliar with the camshaft and how an internal combustion engine works, stick around cause you need to know how it works and why it’s crucial. If you already have a good understanding, then you can skip the next section.
First, the basics: your car’s engine runs by burning fuel and air inside the cylinders. Once the fuel and air mixture combusts, it will force the piston inside the cylinder to move down and rotates a crankshaft underneath the engine.
The crankshaft converts the reciprocating motion of the pistons into a rotational motion. And then this force is transferred to the driven wheels through a series of gears and shafts. That’s essentially how a car works.
Back to that fuel and mixture, it needs to enter the cylinders at the right time. Specifically, during the intake stroke where the piston is moving down to allow space for the mixture before compressing it. The mixture enters the cylinder through valves, known as the intake valves.
The valves are closed by default, so how do you open them? With the help of the camshaft. The camshaft is a rotating shaft with lobes (cams) attached to it. These lobes rotate along with the shaft, and when the lobes come into contact with the intake valve, it will push the valve down to allow fuel and air to enter.
Note there are also exhaust valves in an engine. The exhaust valve works the same way as the intake valve—by using the camshaft to open them. But as the name suggests, the exhaust valves open when the engine needs to expel exhaust gases after combustion.
What’s The Camshaft Position Sensor For?
So, what does the camshaft position sensor do then? Before we explain further, what you should know is that the camshaft and crankshaft are connected via a timing belt or chain, depending on the car’s make and model.
The timing belt/chain is necessary because the camshaft and crankshaft need to be in rhythm. The crankshaft’s position determines the position of the pistons inside the engine, and what stroke of the combustion process each cylinder is in.
By timing the camshaft and crankshaft together with a timing belt/chain, the camshaft can open the correct valves at the correct time. For example, if cylinder 1 is in the exhaust stroke, then a correctly-timed camshaft will open the exhaust valves to allow the exhaust gases to escape.
The camshaft position sensor’s (CMP) role is to determine the camshaft’s position as it relates to the crankshaft. If the timing is off, the CMP will know and can throw a trouble code to alert the driver that something is wrong with the engine.
The CMP sensor also helps the Engine Control Unit (ECU) to control the fuel injectors and ignition timing. It helps to make sure that these devices work correctly at the right time.
If the timing is off or the CMP is faulty, then the ECU can’t control the engine correctly. This can also cause the camshaft to open the valves at the wrong time, which can lead to severe damage. In interference-type engines, this often leads to complete engine failure.
Camshaft Position Sensor Bank 1 Location
So, now you know how a camshaft and its position sensor work. Where exactly is that camshaft position sensor bank 1? Camshaft position sensor bank 1 refers to the sensor in bank 1 of your engine. Okay, that’s pretty self-explanatory, let us explain further:
If you have an inline engine such as an inline-four or inline-six engine, then there’s only one cylinder bank (one row of cylinders). You don’t need to identify the banks, and all you need to do now is find the exact location of the sensor which varies depending on your car’s make and model.
If you have a V-configuration engine, such as a V6, V8, and so on, then you have two cylinder banks or two rows of engine cylinders. This means that each bank has its own camshaft and camshaft position sensor. Bank 1 is always the bank that has cylinder number 1, and the location varies depending on the car’s make and model.
For example, most Ford V8 engines have cylinder number 1 on the passenger side (left side when viewed from the front of the car). This means that’s bank 1, and that’s where the CMP sensor the code is referring to is located.
Meanwhile, most Chevy V8s have cylinder number 1 on the driver’s side. This means that bank 1 is on the driver’s side, and that’s where the CMP sensor you’re looking for is. Note that since each bank has its own camshaft, so it has at least one sensor each.
Crankshaft Position Camshaft Position Correlation Bank 1 Sensor A
In addition to the cylinder bank location, many cars have two sensors on each bank of the engine. The car’s OBD system will refer to the two sensors as sensor “A” and sensor “B”.
This is because most engines nowadays use DOHC (Dual Overhead Cam) technology. As the name suggests, this technology utilizes two camshafts on the engine; one for the intake valves, and one for the exhaust valves.
Since there are two camshafts, the engine needs two CMP sensors to know the position of each camshaft. Sensor “A” usually refers to the camshaft for the intake valves. Meanwhile, sensor “B” is located on the exhaust side of the cylinder head. If the exhaust manifold is on the driver’s side of the engine, that’s where sensor B is.
The sensor is usually a black plastic plug that connects to the engine’s cylinder head (top part of the engine). You’ll see a connector and some wiring that connects it, usually to the car’s ECU.
Of course, the exact location of the sensor varies depending on your car’s make and model. So, we recommend checking your service manual to find the exact location of the sensor. But now you have a general idea of where the sensors are and where to find them.
Camshaft Position Sensor Symptoms
Regardless of what triggered the trouble code indicating your camshaft position sensor issue, it’s not to be taken lightly. Even if the cause isn’t too serious, an error with the CMP sensor can cause driving issues and severe damage in the long run. Here are the symptoms you have a CMP sensor problem:
1. Engine Misfires And Performance Issues
As mentioned, the CMP sensors help the ECU to control various engine components including the fuel injectors and ignition timing. If the CMP is faulty or isn’t in sync with the crankshaft position sensor (CKP), this will give the ECU erroneous readings.
As a result, the ECU won’t be able to inject fuel into the engine and/or ignite it at the correct timing. Resulting in performance issues such as engine misfires and poor acceleration.
This performance issue will often feel like the car is hesitating to accelerate. When you press the gas pedal, a good engine should accelerate and the RPM should climb with no problem whatsoever. But a faulty CMP sensor can cause the RPM to become unstable, or sometimes the car feels like it’s just not as fast as it usually is.
This can also manifest in the car being unable to start. Since it can ruin the ignition timing, the spark plugs will not fire and combust the fuel and air mixture at the right time, causing your car to crank but won’t start.
2. Engine Stalling
Your engine might also stall while you’re driving if you have a CMP sensor-related issue. This can be caused by a fuel injector that isn’t injecting fuel into the engine at the right time, or spark plugs not firing.
In severe cases, it might be because the engine has completely failed due to incorrect camshaft timing. In interference engines, incorrect timing between the camshaft and crankshaft can cause the pistons to come into contact with the valves.
Not only does this damage the pistons, but it will also bend the valves. Once this happens, the valves won’t’ be able to close properly and your engine will seize to work. This type of damage will often require a full engine rebuild.
3. Worse Fuel Consumption
Again, since the CMP sensor affects how the ECU controls the fuel injectors, it can result in bad fuel mileage. Erroneous readings may cause the ECU to inject more fuel into the engine, resulting in higher fuel consumption when it isn’t necessary.
Causes And Diagnosis
The most common trouble codes for CMP sensor issues include the P0016, P0017, and codes P0340 through P0349. For codes P0340 through P0347, the most likely causes are a faulty CMP sensor or damaged wiring. Meanwhile, the P0016, P0017, P0348, and P0349 codes likely mean your engine timing is off.
Note that a low engine oil or incorrect oil viscosity can also trigger these codes. Low engine oil or incorrect oil viscosity can affect the oil flow to the cam phasers (a part of the engine’s Variable Valve Timing system) and causes the camshaft to operate incorrectly.
Here are the steps that we recommend that you take to troubleshoot the problem:
1. Check The Engine Oil
Since a low engine oil can cause your troubles, we recommend checking the engine oil level first. It’s easy enough:
- Perform the test while the engine is cool to get an accurate reading. Wait at least 15 minutes after driving.
- Locate the engine oil dipstick in the engine bay, which usually has a yellow handle that says ‘Engine’.
- Take out the dipstick, and then wipe the oil from the dipstick.
- Reinsert the stick fully back into the slot.
- Pull it out, and inspect the oil. There’s a minimum and maximum marker on the stick, and the engine oil needs to be somewhere in-between the markers.
Most mechanics recommend that your engine oil should be at 3/4 between the minimum and maximum markers. If your engine oil is below the minimum marker, refill it, then reset the check engine light. Afterward, drive for about 10 – 15 minutes and see if the check engine light and trouble code returns.
You should also make sure that your last oil change was done properly with the correct oil viscosity. Putting in the wrong oil in your car can cause a low oil pressure, and this will affect lubrication on the camshaft. If the problem persists, let’s move on to the next step:
2. Scan For Trouble Codes
Always scan the OBD system with your OBD scan tool and see if there are any other codes present. Other codes that indicate a different issue in the car can be the source of your problem.
For example, even if you have enough oil, your car may have low engine oil pressure due to various reasons. Including a faulty oil pump, clogged oil filter, and incorrect oil viscosity. A low engine oil pressure will trigger the P0524 code. And if you see this—or any other trouble codes—you’ll need to rectify that as well.
3. Visually Inspect The Camshaft Position Sensor
If the trouble codes that you see are only CMP sensor-related, then it’s time to take a look at that sensor. Most cars will have the sensor accessible outside of the engine, so you don’t need to disassemble the engine. However, other engine components might get in the way.
In any case, once you locate and can gain access to the sensor, visually inspect it and the wiring. Look for any signs of physical damage to the sensor and the wiring. If the wires, connector, or the sensor itself has physical damage, this is likely the cause of your troubles.
If there’s no sign of damage, then it’s time to test the sensor itself:
4. Bench Test The Camshaft Position Sensor
To do this, you’ll need to disconnect the sensor from its electrical connector and unplug it from the engine. Don’t forget to disconnect the battery’s negative connection before you start working on the car.
Again, note that removing the sensor might require you to remove engine components to gain access, such as removing the air intake tube out of the way. Afterward, you’ll need a socket wrench to remove the sensor itself.
After you got the sensor out, inspect the connector for signs of damage or contaminants. This can cause the sensor to give false readings, but if there aren’t any, here’s how to bench test it with a multimeter:
- Set the multimeter to the Ohm setting. Check your owner’s manual to find out the resistance range for the sensor in your specific car. For example, if it’s between 2,000 and 2,500 Ohms, then set the multimeter to the 20,000 Ohm setting.
- Connect the leads to the sensor, and see if the multimeter is reading somewhere between the resistance specification. If it’s supposed to be 2,000 Ohms and you have a reading below that, then you have a bad sensor.
- You should also test the connector in the engine. Set the multimeter to the continuity test setting, and then connect the negative (black) lead of the multimeter to the battery’s negative terminal.
- Connect the positive (red) lead to the connector, and it should beep if it’s working normally.
The video above is a great visual guide on how to test the CMP sensor. You should also test the sensor for voltage by setting the multimeter on AC volts. Then clamp the leads to the sensor, and rotate a gear in front of the sensor. The reading should change if it’s working properly.
5. Inspect The Engine Timing
If everything seems to be working well so far, then you have good reason to suspect that your engine’s timing is off. Especially if you see the codes P0016, P0017, P0348, and P0349.
Unfortunately, checking the engine’s timing will require you to disassemble the timing belt/chain cover, and often the valve cover as well. This is not an easy job to do, so we recommend taking your car to a trusted auto repair shop instead for diagnosis.
However, there are some signs that you can look out for. If your car has a timing chain, bad engine timing will often produce a rattling noise when the engine is running. Meanwhile, a bad timing belt will usually produce a ticking noise instead.
Camshaft Position Sensor Bank 1 Repairs & Costs
Here are the repairs you need to do depending on your problem and the potential costs:
- Low engine oil pressure. Around $100 for an oil filter replacement. But a faulty oil pump can set you back up to $1,000 to replace depending on the car’s make and model.
- Camshaft sensor replacement cost is between $95 and $200 including labor.
- Wiring repairs are usually $200 – $300 on average depending on the extent of the damage.
- Timing belt/chain repairs depend on whether your car uses a belt or chain. Timing belts are usually around $500 including labor, while the timing chain can cost up to $800 due to the parts being more expensive.
Aside from replacing the oil filter and camshaft position sensor, we don’t recommend doing the job yourself. Replacing the oil pump and timing belt/chain isn’t easy since it requires quite a lot of disassembly. It’s best to leave these two jobs to professionals.
Wiring repairs are also difficult unless you have advanced knowledge and skills in electric engineering, in which case you probably don’t need our help anyway.
Camshaft Position Sensor Bank 1 Replacement
As for replacing an oil filter, you can learn more about how to do that in our guide. And if you have a faulty CMP sensor, here’s how you can replace it on your own:
- Disconnect the car’s negative battery terminal.
- Remove engine components that obstruct access to the sensor.
- Disconnect the sensor’s electrical connector, and then remove it with a socket wrench. Gently remove the sensor once loose.
- Inspect the sensor for signs of coolant or fuel leak, the sensor should be drenched only in oil. If there are other fluids, you’ll need to fix the leak first.
- Install the new camshaft position sensor and tighten it with a socket wrench. Check your service manual if the sensor needs to be torque wrenched, but in any case, don’t overtighten it.
- Reconnect the electrical connector.
- Reinstall engine components that you had to remove.
- Clear the trouble codes to reset the check engine light. Drive the car for about 15 minutes, and if the check engine light doesn’t return, you’ve successfully replaced the sensor.
The video above from O’Reilly Auto Parts shows how to replace it in a 2005 Jeep Liberty. Aside from removing the air filter box, the process is pretty straightforward and you should be able to do it at home with basic hand tools. This can save you between $75 and $100 in labor costs.
Camshaft Position Sensor Bank 1 FAQ
Here are the frequently asked questions about CMP sensors and the answers you might find useful:
What Is A Camshaft
A camshaft is a rotating shaft that sits on top of the engine’s cylinders and has lobes (cams) that attach to it. Hence the name ‘camshaft’. The lobes rotate along with the shaft, and these lobes push the engine’s valves to open at the correct time. The intake valves allow fuel and air to enter the engine, while the exhaust valves allow exhaust gases to escape after the combustion process.
What Do Do After Replacing A Camshaft Sensor
After replacing a camshaft sensor, all you need to do is clear the trouble codes in the car’s On-Board Diagnostic (OBD) system to get rid of the check engine light (if there was one in the first place). Afterward, drive the car for about 15 minutes to verify that the issue is now resolved. If the check engine light returns, you’ll need to check the engine further.
How To Reset Camshaft Position Sensor
A camshaft position sensor cannot be reset. Once it’s faulty, you’ll need to replace it. The only reset you need to do is after you’ve replaced the sensor, which you can do with an OBD scan tool. If the check engine light persists after replacing the sensor, you likely have engine timing issues.
Where Is Camshaft Position Sensor A Bank 1 Located
Bank 1 refers to the row of cylinders (cylinder bank) that contains cylinder 1, which is the cylinder that sits farthest from the engine. If you have a V-configuration engine, this can either be the driver’s side or the passenger side bank, you’ll need to check your car’s service manual to find it as it differs depending on make and model. As for sensor A, the location also differs, but it’s usually the sensor on the opposite side of the car’s exhaust manifold.
What Does Camshaft Position Sensor A Bank 1 Circuit Malfunction Mean
Circuit malfunction means that the ECU is getting a voltage reading from the sensor outside of the accepted value. This usually indicates an electrical problem, which could be caused by a faulty sensor, bad electrical connectors, and/or wiring damage.
Camshaft Position Sensor Bank 1: Wrap Up
Let’s recap: the camshaft position sensor monitors the camshaft’s position and feeds that data to the ECU. This helps the ECU to control fuel injection, ignition timing, and other aspects of the engine to run smoothly.
If you have an inline-configuration engine, then there’s only one bank. But a V-configuration engine has two banks (two rows of engine cylinders). And bank 1 is where cylinder number 1 is located, and each bank has at least one camshaft position sensor.
Any camshaft position sensor issues will cause noticeable symptoms and can make driving uncomfortable. If you’re unlucky, it can also cause severe engine damage that might require a full engine rebuild. So, it’s best not to postpone repairs.
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