What does it mean?
This is a generic powertrain diagnostic trouble code (DTC), meaning it covers all makes/models from 2003 onward. The code appears more common on Kia, Hyundai, Chevrolet, Toyota, and Ford vehicles, but any brand vehicle may be affected. Specific troubleshooting steps vary by vehicle.
These vehicles may have a single camshaft in-block or a single overhead camshaft (SOHC) or dual (DOHC), but this code is strictly concerned with the incoming signal from the camshaft position sensor(s) in Bank 1 being missing, typically at engine startup. It is an electrical circuit fault. Bank #2 is the engine bank that does not contain cylinder #1.
The PCM uses the camshaft position sensor to tell it when the crankshaft sensor signal is correct, when a given crankshaft position sensor signal is timed to cylinder #1 for timing, and it is also used for fuel injector timing/injection start.
P0340 or P0341 codes may also be present alongside P0348. The only difference between these 3 codes is the duration of the issue and the type of electrical problem encountered by the sensor/circuit/engine controller. Troubleshooting steps can vary by manufacturer, camshaft position sensor type, and wire color.
Symptoms
Symptoms of a P0348 engine code may include:
Check Engine Light illuminated
Bucking or Surging
Stalls, but may restart if the issue is inconsistent
May run fine until restarted; will not restart
Potential Causes
Typically, causes for this code are:
Open in the ground circuit to the camshaft position sensor
Open in the signal circuit between the camshaft position sensor and the PCM
Short to 5 volts in the camshaft position sensor signal circuit
Faulty camshaft position sensor – internal short to voltage
Diagnostic and Repair Procedures
A good starting point is always searching for a Technical Service Bulletin (TSB) for your specific vehicle. The vehicle manufacturer may have a PCM flash/reprogram to cover this issue, and it’s worth checking before discovering you’ve taken a long/wrong path.
Next, locate the camshaft and crankshaft position sensors on your specific vehicle. Since they share common power and ground circuits, and this code focuses on the camshaft position sensor’s power and ground circuits, it makes sense to check them for any damage to either. Once located, visually inspect the connectors and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Separate the connectors and carefully inspect the terminals (the metal parts) inside the connectors. See if they look corroded, burnt, or perhaps greenish compared to the normal metal color you’re used to seeing. You can get electrical contact cleaner at any auto parts store if terminal cleaning is needed. If not possible, find 91% rubbing alcohol and a soft plastic-bristled brush to clean them. Then, let them air dry, get some dielectric silicone compound (same as used for light bulb sockets and spark plug wires), and apply it where the terminals make contact.
If you have a scan tool, clear the diagnostic codes from memory and see if this code returns. If not, the connections were likely your problem.
If the code returns, we’ll need to test the sensor and its associated circuits. There are generally 2 types of camshaft position sensors: Hall effect or magnetic sensor. You can usually tell which you have based on the number of wires from the sensor. If there are 3 wires from the sensor, it’s a Hall effect sensor. If it has 2 wires, it will be a magnetic pickup type sensor.
This code will only be set if the sensor is a Hall effect sensor. Disconnect the harness going to the camshaft position sensor. With a digital voltmeter (DVOM), test the 5V power circuit going to the sensor to ensure it’s powered (red wire to the 5V/12V power circuit, black wire to a good ground). Check with a wiring diagram or diagnostic chart if this sensor is supplied with 5 volts or 12 volts. If there are 12 volts at the sensor when there should be 5 volts, repair the wiring from the PCM to the sensor for a short to 12 volts, or possibly a faulty PCM.
If all is well, with a DVOM, check that the camshaft position sensor signal circuit is 5V (red wire to the sensor signal circuit, black wire to a good ground). If there is no 5 volts at the sensor, or if you see 12 volts at the sensor, repair the wiring from the PCM to the sensor, or again a faulty PCM.
If that checks out, verify you have a good ground at each sensor. Connect a test light to the positive 12V battery (red terminal) 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, that would indicate the circuit problem. If it lights up, wiggle the wire harness going to each sensor to see if the test light flickers, indicating an intermittent connection.