Seeing a check engine light pop up on your dashboard is never a great feeling, especially when your car starts running rough. If your OBD2 scanner pulls a P1374 trouble code, you need to address it quickly. Ignoring this issue can lead to sudden engine stalling, terrible fuel economy, or a complete failure to start. The P1374 code generally points to a communication problem between the crankshaft position sensor and the camshaft position sensor, or an issue within the ignition coil control circuit. Figuring out exactly what is causing this mismatch will keep you from getting stranded on the side of the road.

What does a P1374 code mean for your engine?

Modern engines rely on precise timing to run smoothly. The crankshaft position sensor (CKP) and the camshaft position sensor (CMP) constantly send data to the powertrain control module (PCM). When the PCM detects that the frequency signals from these sensors do not align properly, it triggers the P1374 code. This issue is very common in General Motors vehicles, including older Buick, Chevrolet, and Pontiac models. If you are trying to figure out why the timing is off, getting familiar with how this specific engine fault operates will help you narrow down the electrical or mechanical failure.

What symptoms will you actually experience?

You will not always have just a check engine light. A P1374 code usually brings physical drivability issues that are hard to miss.

  • Engine stalling: The car might shut off unexpectedly at stoplights or while driving.
  • Hard starting: The engine cranks for a long time before finally catching, or it might not start at all.
  • Rough idle and misfires: You may feel the car shaking or vibrating when parked.
  • Loss of power: Acceleration feels sluggish, especially when trying to merge onto a highway.

Where should you start testing?

The biggest mistake you can make is immediately buying a new crankshaft sensor. Electrical gremlins often hide in the wiring. Start by visually inspecting the wiring harnesses connected to both the CKP and CMP sensors. Look for frayed wires, melted insulation near the exhaust, or corroded connector pins.

Next, use a digital multimeter to check the resistance and voltage of the sensors. Compare your readings to the factory specifications for your exact vehicle. Following a logical testing sequence for the P1374 code ensures you isolate the actual broken component instead of guessing. When printing out factory wiring diagrams to trace these circuits, using a clean, legible typeface like Montserrat can save your eyes from straining under dim garage lighting.

Are there other common causes besides bad sensors?

Sensors do fail, but they are not the only culprits. A damaged reluctor ring, which is the notched wheel the sensor reads, can easily cause a P1374 code. If the ring is cracked or has debris stuck in the teeth, the sensor will send erratic signals. Additionally, problems in the ignition coil primary circuit, such as a failing coil pack or worn spark plugs, can sometimes trigger related timing faults. Before ordering replacement parts, check our detailed breakdown of this vehicle code to see if your specific make and model has a known technical service bulletin regarding the wiring harness.

What should you avoid doing?

Do not just clear the code with a scanner and hope it stays away. The P1374 code will return as soon as the PCM runs its self-check and detects the signal mismatch again. Avoid using cheap, aftermarket sensors if possible. Original equipment manufacturer sensors are highly recommended for crankshaft and camshaft position circuits because cheap alternatives often have inconsistent internal resistance that confuses the PCM.

Practical next steps for your repair

Before you tear into the engine, work through this quick diagnostic checklist to save time and money:

  1. Scan the vehicle and write down all pending and stored codes to check for related ignition or sensor faults.
  2. Perform a visual inspection of the CKP and CMP sensor wiring harnesses, paying special attention to areas near hot exhaust components.
  3. Test the sensor resistance with a multimeter and compare it to the factory service manual specifications.
  4. Inspect the reluctor wheel through the sensor mounting hole using a small borescope camera to check for missing teeth or debris.
  5. Swap the ignition coils to see if a related misfire moves to a different cylinder before condemning the timing sensors.