Engine Code P1374 Causes and Solutions

Seeing a check engine light is frustrating, but it becomes a real problem when your vehicle suddenly stalls or refuses to start. If your OBD2 scanner pulls a P1374 code, your car's computer is receiving conflicting signals about the engine's timing. Understanding the exact engine code P1374 causes is the first step to fixing the issue before it leaves you stranded. If you want to dig deeper into the technical definition, reading up on the meaning behind this specific fault can give you a better idea of how the sensors communicate.

What exactly is triggering the P1374 code?

Most often, this trouble code pops up in General Motors vehicles equipped with the 3.8L V6 engine. The crankshaft position sensor (CKP) sends two different signals to the ignition control module: a 3X signal and a 24X signal. When the computer detects a mismatch between the high and low frequency signals, it triggers the code. Getting a proper breakdown of how the CKP system works helps clarify why the engine control module gets confused.

What are the most common engine code P1374 causes?

You might assume you just need a new sensor, but jumping to conclusions can waste money. Reviewing a detailed list of specific component failures that trigger this code will save you from buying unnecessary parts. Here is what typically goes wrong:

Failing Crankshaft Position Sensor: The internal components wear out over time and stop reading the reluctor wheel accurately.
Damaged Wiring or Connectors: Heat and vibration from the engine block can cause wires leading to the sensor to melt, chafe, or break entirely.
Faulty Ignition Control Module (ICM): Since the ICM processes the CKP signals, a bad module can easily create a false mismatch error.
Worn Harmonic Balancer: If the rubber in the balancer separates, the outer ring slips. This throws off the timing marks the sensor reads.

How do you know if it's the sensor or the wiring?

Before replacing parts, grab a digital multimeter. Check the reference voltage and ground at the sensor connector while the key is in the ON position. If you have the correct voltage, the wiring is likely fine, pointing to a bad sensor. If the voltage drops or fluctuates, you have a wiring harness issue. It often helps to print out the wiring diagram for your specific model year. Make sure your document is set to a clear, readable typeface like Open Sans so you can easily trace the circuits in the garage.

What mistakes do people make when fixing this?

The biggest error is clearing the code with a scanner and hoping it stays away. The P1374 code will return because the underlying electrical or mechanical fault still exists. Another frequent mistake is buying the cheapest aftermarket crankshaft position sensor available. Engine management sensors are highly sensitive, and cheap alternatives often fail within a few months or provide erratic readings right out of the box. Finally, mechanics sometimes forget to inspect the reluctor ring on the harmonic balancer. If the metal teeth are damaged or covered in heavy metallic debris, a brand new sensor will still fail to read the signal.

What should you do next to get your car running right?

Taking a systematic approach prevents wasted time and money. Follow this practical checklist to resolve the issue:

Scan the vehicle to confirm P1374 is the only active code. If you also see misfire codes, the ignition control module is a prime suspect.
Visually inspect the wiring harness running from the crankshaft sensor to the ICM. Look for melted insulation near the exhaust manifold.
Test the sensor's resistance with a multimeter and compare the reading to factory specifications.
Check the harmonic balancer for any signs of wobbling while the engine is running.
Replace the faulty component, clear the codes, and take the car for a test drive to ensure the engine timing signals remain stable.