Guide To P0391 OBD Error Code Solutions

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The P0391 error code would start indicating that the problem is on the side of the engine which does not contain cylinder #1 due to poor sensors as well as connectors. It is a generic OBD-II code which can be defined as Camshaft Position Sensor B Circuit Range/Performance Bank 2. The sensor B would refer to the exhaust camshaft side while on the other hand Bank 2 would indicate that the issue is on the side of the car engine which does not contain cylinder #1.

The PCM is being told by the camshaft position sensor that in what position the camshaft is in and it would help to facilitate the proper fuel delivery as well as ignition timing. The signal is then sent to the powertrain control module by the sensor in the form of a voltage reading. If the reading would deviate from the expected specifications, then the computer would detect that there is some issue with the camshaft position and it would trigger the P0391 error code.

What causes this problem with the Camshaft Position Sensor "B" Circuit Range/Performance (Bank 2)?

• The crankshaft position sensor might have some flaws
• An open or short in the sensor circuit
• There can be some bad connectors
• Faults in the starter motor
• There can be compromised battery function
• Quirks in the starting system circuitry

1. Camshaft Position Sensor - The P0391 code can also arise due to some issues in Camshaft Position Sensor. So, it is advised to replace them as soon as possible.
2. Crankshaft Position Sensor - Do you remember when was the last time you got your car Crankshaft Position Sensor checked up? A damaged Crankshaft Position Sensor can cause a lot of issues like displaying P0391 code.
3. Engine Control Module - Engine Control Module is an important car part which should never be neglected. May be there is some fault in it due to which P0391 code may start flashing.
4. Fuel Injector - Is your Fuel Injector damaged or broken? Don’t worry as we have solutions for all your problems.
5. Ignition Coil - Defective car Ignition Coil can be a major reason why P0391 code depicts. So, make sure to replace it online so that you don’t have to face any further issues.
6. Exhaust System Parts - Everything is okay with the Fuel Injector and still OBD code P0391 triggering? Then there must be some defects in Exhaust System Parts. Replace them as soon as possible.
7. Cylinder Head Gasket - P0391 code flashing? Get your Cylinder Head Gasket inspected from a mechanic.
8. Powertrain Control Module - Powertrain Control Module is an important auto part. Take care of it and you can rely on us to purchase best quality Powertrain Control Module online.

Willing to know some common symptoms of OBD Trouble Code P0391? Your wish is our demand. Have a look at them below:

Common Symptoms

• The car may not be able to start properly
• Vehicle cat start running roughly or may misfire
• Malfunction indicator lamp can start illuminating

If you wish to correct this fault code, then you have to follow certain steps. Correcting a problem needs your careful attention. Here are some ways with the help of which you will be able to correct the OBD Code P0391:

• Repairing the defected wiring or connectors
• The starter motor should be replaced
• If the battery is weak, then it should be charged or repaired properly
• You can always replace the crankshaft position sensor
• The camshaft position sensor harness should be repaired as per the need
• Repair the fluid leaks which may be damaging the sensor circuitry

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If you want to easily diagnose this fault code, then all you have to do is to follow the steps which are mentioned below:

• You must verify any existing diagnostic trouble codes using a scanner and recording relevant data, such as the order in which the codes occurred
• All the codes should be cleared and road testing the vehicle above 45mph in order to see if the codes return
• Diagnose and repair any errors which occurred prior to the camshaft sensor circuit problem
• You must visually inspect the relevant wiring and connectors to check for corrosion, shorts, opens, or loose connections
• Visually inspecting the circuitry for signs of engine oil or other fluids which may have spilled over, causing damage to the sensor or wiring
• Test the resistance and voltage of the camshaft position sensor and connector
• A digital volt/ohmmeter should be used to test the system continuity

You must keep in mind that some vehicles will set a camshaft sensor code when there is a faulty crankshaft sensor, so you may need to look into that possibility if none of the above diagnoses pan out.

Common Mistakes When Diagnosing The P0391 Code

• Most of the times errors would be made by automatically assuming that there is some issue with the sensor, rather than actually examining and replacing any faulty wiring or connectors
• The next mistake is that if a circuitry problem is being caused by a leak, then the issue won’t be fixed by replacing the faulty parts. Keep in mind to address other malfunctions in order to prevent the code coming back again