P0340 vs. P0335: Why You Should Replace Camshaft and Crankshaft Sensors Together

If you are dealing with a Hyundai or Kia that struggles to start, you might see code P0335 (Crankshaft Position Sensor). But sometimes, you might also see P0340 (Camshaft Position Sensor).

Are they the same thing? No.
Should you replace both? Yes, and here is why.

1. The Dynamic Duo: How They Work

Your engine relies on timing.

• Crankshaft Sensor (CKP - P0335): Tells the computer how fast the engine is spinning (RPM).

• Camshaft Sensor (CMP - P0340): Tells the computer which cylinder is ready to fire (Timing).

They work in perfect sync. If the data from these two sensors doesn't match up, your ECU gets confused, leading to P0016 codes, rough idling, or a car that enters "Limp Mode."

2. Why Do They Fail Together?

It's not a coincidence.

1. Same Age: Both sensors were installed on the day your car was built. They have the same mileage.

2. Same Environment: Both sensors live on the engine block. They endure the same extreme heat cycles, vibration, and oil exposure.

3. Plastic Fatigue: The plastic housing on Hyundai/Kia sensors becomes brittle over time. If the Crank sensor cracked from heat, the Cam sensor is likely brittle too.

If you only replace one, you might find yourself back under the hood in 3 months replacing the other one.

3. Diagnostic Tips

• P0335 Symptoms: Tachometer stays at 0, car cranks but won't start.
  👉 [Read More: Symptoms of a Failing Crank Sensor] 

• P0340 Symptoms: Car starts but runs very rough, misfires, poor acceleration.

If you have high mileage (over 100,000 miles), treating these as "maintenance items" rather than "repair items" is a smart move.

4. Save Time and Money

You are already getting your hands dirty (or paying a mechanic labor costs).
The Camshaft sensor is usually located right on top of the engine (very easy to reach), while the Crankshaft sensor is lower down.

Buying a bundle or adding both to your cart ensures you restore your engine's timing system to 100% health in one go.

Need parts for your Hyundai i30 or Kia Ceed?
We have the high-quality replacement parts you need.

• Crank Sensor: [39265-2U100] 

• Cam Sensor: [Shop Camshaft Sensors]