P1397 Camshaft position sensor 2

P1397 Camshaft position sensor 2

A P1397 trouble code can have different meanings depending on the vehicle manufacturer, but it is often associated with the camshaft position (CMP) sensor for engine bank 2

. A bad or intermittent signal from this sensor can disrupt the engine's timing, causing performance issues. 

What the code means

• P1397 is a manufacturer-specific code, so its exact definition varies by make and model.
• For many vehicles, particularly those with a V-engine configuration, the P1397 code signifies an issue with the "B" camshaft position sensor on bank 1, which typically monitors the exhaust camshaft.
• The powertrain control module (PCM) uses the CMP sensor to track the camshaft's rotation relative to the crankshaft, which is critical for controlling spark timing and fuel injection.
• The code is set when the PCM detects an inconsistent or incorrect signal from the sensor. 

Common symptoms

A faulty camshaft position sensor can lead to a number of noticeable symptoms, including:

• An illuminated Check Engine Light on the dashboard.
• Rough idling, which may worsen when the engine is cold.
• Engine misfires, causing the engine to run roughly.
• Engine stalling, especially at low RPMs.
• Poor engine performance, including reduced power and acceleration.
• The engine may be hard to start or may not start at all. 

Common causes

Potential causes for this error code can include:

• Faulty CMP sensor: The sensor itself can fail due to age or high temperatures.
• Wiring and connection issues: Damaged, corroded, or loose wiring and connectors can cause an intermittent signal.
• Engine timing problems: Issues with the timing chain or timing belt, such as stretching or jumping a tooth, can cause a timing misalignment.
• Oil sludge: In some engines, sludge can build up and interfere with the sensor or the variable valve timing (VANOS in BMWs) system, causing the error.
• Faulty variable valve timing (VVT) actuator: Problems with the VVT system can affect camshaft timing and trigger the code. 

How to diagnose and fix it

To accurately diagnose and fix a P1397 code, follow these steps:

1. Inspect the wiring: Visually check the wiring harness and electrical connector for the camshaft position sensor on bank 2 for any signs of damage, corrosion, or looseness.
2. Test the sensor: A professional can use an oscilloscope to test the sensor's voltage and signal pattern. In some cases, a faulty sensor can be confirmed by swapping it with the sensor from bank 1 and seeing if the code follows.
3. Check for timing issues: An experienced mechanic can check the engine's timing chain or belt for wear or slack that could be causing timing inaccuracies.
4. Replace the sensor: If the sensor is found to be faulty, it should be replaced. For some vehicles, it is critical to use a high-quality, OEM sensor to ensure proper function.
5. Clear the code: After inspecting and repairing the issue, use an OBD-II scanner to clear the code and confirm the repair.