Ignoring engine code P1374 causes can quickly turn a minor electrical glitch into a dangerous situation where your car stalls in the middle of an intersection. This diagnostic trouble code tells you that the powertrain control module is losing its signal from the 24X crankshaft position sensor. When the computer cannot accurately track how fast the engine is spinning, it struggles to time the spark plugs and fuel injectors correctly. Understanding these triggers helps you fix the car before it leaves you stranded on the side of the road.

Why did my check engine light come on with code P1374?

This code is most common on General Motors vehicles. The engine relies on two different crankshaft sensors to manage timing: a 7X sensor for low speeds and a 24X sensor for smoother idle and higher precision. Code P1374 means the computer is receiving an erratic or high-frequency signal from that 24X circuit. When you start looking into the specific engine code P1374 causes, you will usually find an interruption in this specific sensor loop rather than a catastrophic mechanical failure. You can verify this by checking the exact vehicle code P1374 definition for your specific make and model year.

What parts fail to trigger a P1374 code?

The problem usually stems from the electrical path between the sensor and the computer. Here are the most frequent culprits:

• A failing crankshaft position sensor: Internal components degrade over time due to engine heat and vibration, causing the sensor to drop its signal entirely.
• Damaged wiring or connectors: The wiring harness runs close to hot engine components. Melted insulation, chafed wires, or corroded plug terminals will interrupt the 24X reference voltage.
• Debris on the reluctor wheel: Metal shavings from normal engine wear can stick to the magnetic tip of the sensor, distorting the signal it sends back to the computer.
• A bad powertrain control module: While rare, the main computer itself can fail and misread perfectly good sensor data.

Figuring out which of these issues applies to your car requires a multimeter and some basic electrical testing. It is never a good idea to just replace parts blindly based on a single scan tool reading.

Can I keep driving with a P1374 engine code?

Driving with this code is risky. While the 7X sensor can take over if the 24X sensor fails, the engine will run poorly. You might experience a rough idle, hesitation when you press the gas pedal, or sudden stalling when coming to a stop. Because the engine loses its precise timing data, the check engine light will stay on, and your fuel economy will drop noticeably. It is best to find a safe place to park and review the complete diagnostic steps for this code before driving the car to a repair shop.

How do you test the 24X reference circuit?

Mechanics start by clearing the code and seeing if it returns immediately. If it does, they check the sensor's electrical connector for the proper 12-volt supply, ground, and signal return. An oscilloscope is the best tool for this, as it shows the actual wave pattern the sensor produces. If you plan to print the factory service manual to follow along with the wiring diagrams, make sure your PDF uses a highly legible typeface like Roboto so you can easily read the pinout numbers under the hood.

If the wiring has good continuity and proper voltage, the sensor itself is likely dead. However, you must also inspect the reluctor wheel on the crankshaft. If it is cracked or missing teeth, a new sensor will not fix the problem. Taking the time to isolate the electrical fault prevents you from wasting money on parts you do not need. Understanding the relationship between the sensor and the computer is the fastest way to narrow down all the reasons behind an engine code P1374.

What should you do next?

Follow this short checklist to address the issue safely and logically:

1. Scan the vehicle with an OBD2 reader to confirm P1374 is the only code present.
2. Visually inspect the wiring harness leading to the crankshaft position sensor for burns, cuts, or loose plugs.
3. Clean the tip of the sensor to remove any magnetic metal debris.
4. Use a digital multimeter to test the sensor resistance and circuit voltage against factory specifications.
5. Replace the crankshaft position sensor only if the wiring tests perfectly and the sensor fails the resistance check.