Technical Description of OBD-II Trouble Code
The Camshaft Position Sensor B Circuit High Input (Bank 2)
What does that signify?
This is a generic powertrain diagnostic trouble code (DTC) that applies to all makes and models starting from around 2003. While this code is more commonly found in Kia, Hyundai, Chevrolet, Toyota, and Ford vehicles, it can affect any make of vehicle.
The specific troubleshooting steps will vary depending on the vehicle.
These vehicles may have a single camshaft in block, or a single (SOHC) or dual (DOHC) overhead camshafts. However, this code specifically refers to the absence of the incoming signal from the camshaft position sensor(s) “B” from Bank 1, typically during engine start-up. This indicates an electrical circuit fault. Bank #2 refers to the bank of the engine that does not contain cylinder #1.
The PCM utilizes the Camshaft Position Sensor to determine the accuracy of the Crankshaft Sensor signal, the timing of a given Crankshaft Position Sensor signal to Cylinder #1, and for fuel injector synchronization and start of injection.
Codes P0390 or P0391 may also be present simultaneously with the P0393. The only difference between these three codes is the duration of the problem and the type of electrical issue that the sensor/circuit/engine controller is experiencing. Troubleshooting steps may vary depending on the manufacturer, type of camshaft position sensor, and wire colors.
Symptoms
The symptoms associated with a P0393 engine code may include:
Potential Causes
The typical causes for this code are:
Diagnostic and Repair Procedures
A good starting point is always to search for any technical service bulletins (TSBs) related to your specific vehicle. The vehicle manufacturer may have a PCM flash/reprogram available to address this issue, so it is worth checking before pursuing other troubleshooting steps.
Next, locate both the Camshaft and Crankshaft Position Sensors on your particular vehicle. Since they share common power and ground circuits, and this code focuses on the power and ground circuits of the Camshaft Position Sensor, it is logical to inspect them for any damage. Once located, visually inspect the connectors and wiring for any signs of chafing, rubbing, bare wires, burn spots, or melted plastic. Separate the connectors and carefully examine the terminals inside. Look for signs of corrosion, burning, or a green color instead of the normal metal color. If necessary, use Electrical Contact cleaner or rubbing alcohol and a light plastic bristle brush to clean the terminals. After cleaning, let them air dry and apply some dielectric silicone compound where the terminals make contact.
If you have a scan tool, clear the diagnostic trouble codes from memory and see if this code reappears. If it does not, then the issue was likely related to the connections.
If the code does return, further testing of the sensor and its associated circuits is necessary. Typically, there are two types of Camshaft Position Sensors: Hall Effect or Magnetic Pick up. You can determine which type you have by the number of wires coming from the sensor. If there are three wires, it is a Hall Effect sensor. If there are two wires, it is a Magnetic Pick up style sensor.
This code will only be triggered if the sensor is a Hall Effect sensor. Disconnect the harness going to the Camshaft Position Sensor and use a Digital Volt Ohm Meter (DVOM) to test the 5V power supply circuit to ensure it is receiving power (Red lead to the 5V/12V power supply circuit, black lead to a good ground). Refer to a wiring diagram or diagnostic chart to determine if this sensor should be powered with 5 volts or 12 volts. If there is 12 volts instead of 5 volts, repair the wiring from the PCM to the sensor for a short to 12 volts or consider a possible issue with the PCM.
If that checks out, use a DVOM to verify that there is 5V on the Camshaft Position Sensor signal circuit (Red lead to the sensor signal circuit, black lead to a good ground). If there is no 5 volts or if you see 12 volts instead, repair the wiring from the PCM to the sensor or consider a possible issue with the PCM.
If that is also fine, check for a good ground at each sensor. Connect a test light to the positive terminal of a 12V battery and touch the other end of the test light to the ground circuit going to the Camshaft Sensor circuit ground. If the test light does not illuminate, it indicates a problem with the circuit. If the test light does illuminate, wiggle the wiring harness going to each sensor to see if the test light flickers, indicating an intermittent connection.
Related Camshaft Trouble Codes: P0340, P0341, P0342, P0343, P0345, P0346, P0347, P0348, P0349, P0365, P0366, P0367, P0368, P0369, P0390, P0391, P0392, P0394.
