P1399 Honda: Understanding, Diagnosing, and Fixing This Trouble Code

The P1399 Honda code is a generic error code related to the engine management system. More specifically, it indicates an intermittent problem in the Camshaft Position (CMP) Sensor ‘B’ circuit. This code is often accompanied by the check engine light illuminating on your dashboard. Understanding the meaning of this code, its potential causes, and possible solutions is essential for any owner of a Honda Civic, Accord, CR-V, or any other model from the brand, to avoid more serious performance issues.

What does the P1399 code mean on a Honda?

The P1399 Honda code relates directly to the engine’s timing and synchronization system. The Camshaft Position Sensor ‘B’ (usually the one for the second camshaft on a multi-cam engine) sends a signal to the Powertrain Control Module (ECM/PCM). This signal allows the computer to determine the exact position of the pistons and perfectly synchronize fuel injection and spark plug ignition. When the PCM detects an irregular, intermittent, or missing signal from this sensor, it records the P1399 Honda trouble code and turns on the check engine light to alert the driver.

Common Symptoms of the P1399 Code

It is crucial to recognize the warning signs associated with this fault. Symptoms can vary in intensity:

• Check Engine Light Illumination: This is the most obvious sign.
• Starting Problems: The engine may take longer to start or may stall immediately after starting.
• Irregular Idle: The engine may shake or have a rough and unstable idle.
• Loss of Power and Poor Acceleration: The car lacks responsiveness and seems to be down on power.
• Increased Fuel Consumption: Poor timing leads to inefficient combustion.
• Jerking and Hesitation during acceleration.

Main Causes of the P1399 Honda Code

Several components can be the source of this trouble code. An accurate diagnosis is necessary to avoid replacing parts unnecessarily.

• Faulty Camshaft Position (CMP) Sensor: This is the most common cause. The sensor itself may be faulty.
• Damaged Wiring or Loose Connector: Engine vibrations can damage the wiring or loosen a connector, creating an intermittent signal interruption.
• Problem with the Timing Belt: A worn, loose, or jumped timing belt can disrupt the synchronization between the camshaft and crankshaft, misleading the sensor.
• Problem with the Sensor Target (Rotor or Reluctor Wheel): On the camshaft, the target that the sensor reads can be damaged or dirty.
• Problem with the PCM: Although rarer, the engine control module itself may be faulty.

How to Diagnose and Repair the P1399 Fault?

It is recommended to consult a professional mechanic with an advanced diagnostic tool. However, here are the general steps to investigate the P1399 Honda code:

1. Visual Inspection: Start with a thorough inspection of the wiring and connector of the ‘B’ camshaft position sensor. Look for any signs of wear, burning, corrosion, or damage. Make sure the connector is fully seated.

2. Sensor and Circuit Testing: Using a multimeter, a technician can check the sensor’s supply voltage and ground. They can also test the sensor’s resistance and check the output signal using an oscilloscope while the engine is running. An irregular signal will confirm the fault.

3. Checking the Timing: It is imperative to check the alignment of the timing belt marks to ensure the synchronization between the crankshaft and camshaft is correct.

4. Replacement or Repair: Depending on the identified cause, the repair will involve: tightening a connector, repairing or replacing a damaged wiring harness, or most commonly, replacing the faulty camshaft position sensor. After any repair, the trouble code must be cleared with the diagnostic tool, and a road test should be performed to confirm the problem does not return.

Conclusion: Don’t Ignore the P1399 Code

Although your Honda may seem to run almost normally with a P1399 Honda code, you should not ignore this problem. A bad signal from the camshaft position sensor can lead to incorrect combustion, eventually damaging the catalytic converter and significantly increasing repair costs. Furthermore, in rare cases, a timing issue could potentially cause serious internal engine damage if the timing belt is involved. Prompt diagnosis and repair by a qualified professional are key to ensuring the longevity and optimal performance of your Honda vehicle.