When your check engine light turns on and an OBD-II scanner reads P1379, it usually points to a problem with your engine's variable valve timing system. For most Honda and Acura vehicles, this specific fault means the computer is detecting an issue with the VTEC oil pressure switch circuit. Knowing the meaning of code P1379 matters because ignoring it prevents your engine from switching to its high-performance cam profile, resulting in sluggish acceleration and poor fuel economy. More importantly, if the code is triggered by genuinely low oil pressure, driving the car could cause severe internal engine damage.

What exactly does this fault code mean?

In most modern applications, this diagnostic trouble code indicates that the powertrain control module sees a high voltage or open circuit in the VTEC oil pressure switch. The computer uses this switch to verify that there is enough oil pressure to safely engage the high-RPM valve lift mechanism. If the switch fails to send the correct signal, the system defaults to a safe, low-RPM mode. While this is primarily a Honda or Acura issue, taking the time to find the exact definition for your specific make is important, as some older General Motors vehicles use this same code for an ignition system failure.

What symptoms will you notice while driving?

You will almost always see an illuminated check engine light. Beyond the dashboard warning, the most noticeable symptom is a lack of power when you press the gas pedal hard. The engine will feel like it hits a wall around 4,000 to 5,000 RPM because the high-lift camshafts never engage. You might also experience a rough idle or slightly decreased gas mileage. Recognizing these physical symptoms helps confirm the issue when your scanner pulls this specific powertrain fault.

What causes the oil pressure switch circuit to fail?

The root cause is not always a broken electrical part. Often, the physical conditions inside the engine trigger the electrical warning. Here are the most frequent culprits:

  • Low engine oil level: This is the most common reason. If the oil is below the minimum mark on the dipstick, the pump cannot generate enough pressure to trigger the switch.
  • Dirty or degraded oil: Sludge and metal shavings can clog the small screen filter located just behind the VTEC solenoid, blocking oil flow to the pressure switch.
  • Faulty pressure switch: The switch itself can fail internally, sending a constant high-voltage signal to the computer even when oil pressure is perfectly fine.
  • Wiring damage: A frayed wire, corroded connector, or bad ground near the switch will break the circuit and trigger the code.

How do you diagnose and fix the problem?

Start with the simplest and cheapest solutions before replacing any parts. First, park the car on level ground, turn off the engine, and check the oil level with the dipstick. If it is low, top it off with the correct viscosity, clear the code with your scanner, and drive the car to see if the light returns. If the oil level is fine, inspect the wiring harness connected to the VTEC pressure switch, which is usually located near the oil filter or the VTEC solenoid on the cylinder head. Look for brittle insulation or green corrosion on the pins.

If the wiring looks good and the oil is full, the switch itself is likely dead. You can test it with a multimeter to check for continuity when the engine is running, but many mechanics simply replace it since the part is relatively inexpensive. If you want to read a deeper breakdown of this particular circuit malfunction, consulting a factory service manual will give you the exact pinout diagrams and voltage specifications for your exact engine.

What mistakes should you avoid during the repair?

The biggest mistake is throwing a new pressure switch at the car without checking the oil level first. If your engine is burning oil or leaking, the new switch will just trigger the same code a few days later. Another common error is ignoring the VTEC solenoid screen. When you remove the solenoid to access the area, check the small metal mesh screen. If it is packed with black sludge, clean it out. Otherwise, the new switch will still starve for oil pressure. Finally, never use the wrong oil weight. Using a thicker oil than the manufacturer recommends can alter the pressure readings and cause the valve timing system to act unpredictably.

If you prefer to print out your factory service manual or wiring diagrams to keep in the garage, formatting the document in a clean, highly legible typeface like Montserrat makes reading small text and complex schematics much easier under harsh lighting.

Practical next steps to get your car running right

Follow this quick checklist to resolve the issue safely and efficiently:

  1. Check your engine oil level immediately and top it off if it is low.
  2. Inspect the oil condition and change it if it looks dark, gritty, or smells burnt.
  3. Locate the VTEC oil pressure switch and visually inspect the connector for corrosion or broken wires.
  4. Remove the VTEC solenoid and clean the small mesh filter screen if it is clogged with debris.
  5. Test or replace the oil pressure switch if the mechanical and visual checks do not solve the problem.
  6. Clear the diagnostic code and take the car for a test drive, ensuring the engine revs past 5,000 RPM to verify the high-lift camshafts engage properly.