When your check engine light turns on and an OBD-II scanner displays a P1374, your car is telling you it has lost track of the engine's precise timing. Getting to the meaning of code P1374 matters right away because this specific fault can cause your engine to stall at a stoplight or refuse to start entirely. It points directly to a communication breakdown between the crankshaft position sensor and the engine control module.

What exactly does trouble code P1374 mean?

This diagnostic trouble code is primarily found in General Motors vehicles. It specifically indicates a crankshaft position high to low resolution frequency correlation issue. Inside the engine, the crankshaft position sensor sends two separate signals to the computer: a high-resolution 24X signal and a low-resolution 3X signal. The computer compares these two signals to manage ignition timing and fuel injection. If the signals do not match up, the system sets a fault. If you need more context on how these signals interact, understanding the deeper explanation of this vehicle code will clarify the mechanical relationship between the sensor and the reluctor wheel.

What symptoms will my car show?

You will not just see a dashboard warning light. The engine relies heavily on crankshaft data to run smoothly. When that data is corrupted, drivers typically experience several noticeable problems.

  • The engine stalls unexpectedly, especially at low speeds or idle.
  • The vehicle struggles to accelerate or feels sluggish.
  • The car cranks but will not start.
  • The tachometer might drop to zero or bounce erratically while driving.

Why did this code trigger in my engine?

The most frequent culprit is a failing crankshaft position sensor. Over time, the internal electronics in the sensor break down from constant heat and vibration. However, the sensor is not always to blame. Damaged wiring, corroded connector pins, or a cracked reluctor ring on the crankshaft can also distort the signal. Before buying replacement parts, looking up the official diagnostic trouble code definition helps confirm that you are testing the right components for your specific car model.

How do you test for this sensor fault?

A proper diagnosis starts with a visual inspection of the wiring harness leading to the crankshaft position sensor. Look for frayed wires, melted insulation near the exhaust, or loose plugs. Next, a mechanic will use a digital multimeter or an oscilloscope to check the sensor's voltage output while the engine cranks. If you are reading a digital factory service manual during this process, making sure the document uses a clear typeface like Open Sans can help reduce eye strain when tracing complex wiring diagrams. If the wiring checks out and the voltage is abnormal, the sensor itself usually needs to be replaced.

What are the most common mistakes when fixing this?

Many DIY mechanics immediately replace the engine control module when they see a correlation code, assuming the computer is broken. This is an expensive mistake. The computer is rarely the problem. Another common error is installing a cheap, aftermarket sensor that fails within a few months. It is also common to clear the code and drive the car without fixing anything, hoping the issue will go away. To avoid these pitfalls, reviewing the specific meaning of the P1374 fault reminds you to focus on the wiring and the physical condition of the sensor first.

What should you do right now?

If your car is currently showing this code, follow these immediate steps to get back on the road safely:

  1. Pull over safely if the engine begins to misfire or stall in traffic.
  2. Scan the vehicle again to see if any other codes, like camshaft position faults, are present alongside P1374.
  3. Pop the hood and trace the wiring from the crankshaft position sensor to the main harness, checking for rodent damage or heat burns.
  4. Test the electrical connector for a solid 12-volt reference and a clean ground.
  5. Replace the crankshaft position sensor with an original equipment manufacturer part if the wiring is perfectly intact but the signal remains out of range.