Fault code P0390 is called “Camshaft Position Sensor “B” Circuit Malfunction (Bank 2)” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P0390
This Diagnostic Trouble Code (DTC) is a general powertrain code. Error P0390 is considered a generic code because it applies to all makes and models of vehicles (1996 and newer). Although the specific repair steps may vary slightly depending on the model.
This code indicates that a problem has been detected in the camshaft position sensor “B” circuit (Bank 2). Since it is a circuit, it means that the problem can lie in any part of the circuit (the sensor itself, the wiring or the ECU). Therefore, the problem does not always lie in the camshaft position sensor itself.
Symptoms of vehicle malfunctions
The main signal that an error P0390 has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- Hard starting or no start.
- Hard starting with ignition skips.
- Loss of engine power.
The fault P0390 is quite serious, as its occurrence may cause problems with the engine. The car may start with difficulty or not start at all, also a loss of engine power is possible. If this code is detected, it is recommended to eliminate the problem as soon as possible.
Factors that can cause this error code
The error code P0390 can mean that one or more of the following problems have occurred:
- Wires or connectors in circuit may be grounded, shorted, or broken.
- The camshaft position sensor may have failed.
- There may have been a malfunction in the ECU.
- There is an open circuit.
- Crankshaft position sensor may be faulty.
How to fix or reset OBD-2 code P0390
Some suggested steps for troubleshooting and fix the error code P0390:
- Visual inspection of all wiring and connectors in the circuit.
- Check continuity of circuit wiring.
- Check operation (voltage) of camshaft position sensor.
- If necessary, replace “B” camshaft position sensor.
- Also check crankshaft position circuitry.
- Replace circuit wiring and/or connectors if necessary.
- Diagnose/replace ECU as necessary.
Diagnose and repair of problems
When starting to diagnose the P0390 fault, check the engine or look at the vehicle’s maintenance history for any recent repairs to the timing belt. Also check the camshaft sensor or crankshaft sensor.
With the ignition off, remove the plug from the camshaft sensor. Turn on the ignition and make sure the tester is lit between terminal 1 of the ignition voltage circuit and the ground.
Use the tester to check for a ground short or open/high resistance in the ignition voltage circuit. If the circuit check is passed and the ignition circuit fuse is open. Check all components connected to the ignition circuit and replace if necessary.
Connect a tester between ground terminal 2 and ignition voltage terminal 1. Verify that the tester lights up. If the tester does not light, check the ground circuit for open/high resistance.
Turn on ignition, check 4.2-5.2 V between terminal 3 of signal circuit and terminal 2 of ground circuit. If the signal range is lower than specified, check the signal circuit for a short to ground or open/high resistance. Make sure the circuit check is correct and replace the electronic module.
If above the specified range, check the signal circuit for a short to voltage. If the circuit check is correct, replace the electronic module.
Check the following conditions if repair work has been carried out before error P0390 appears:
- Correct installation of camshaft sensor.
- Correct installation of crankshaft sensor.
- Problem with the timing belt tensioner.
- Incorrectly installed timing belt.
- Jumped sprocket teeth through timing belt.
- Crankshaft cogwheel or camshaft rheumatic sensor is offset from the upper dead center position (TDC) on the crankshaft.
If any of the above conditions occur, make the necessary repairs.
On which vehicles does this problem occur most frequently
Fault code P0390 can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- BMW
- Dodge (Caravan, Journey)
- Ford (F-150)
- Lexus (GS300, IS250)
- Subaru (Forester)
- Toyota (Camry)
Fault code P0390 can sometimes be found with other errors. The most common are the following: P0335, P0340, P0345, P0349, P0394, P0420, P0606.