Symptoms of a Bad Position Sensor

Your vehicle relies on crankshaft and camshaft position sensors to help the engine computer coordinate ignition, fuel delivery, and engine timing. When one of these sensors begins sending inaccurate or intermittent signals, you may notice anything from hard starting and rough running to unexpected stalling.

Understanding the symptoms can help you determine when your vehicle needs a diagnostic inspection.

What Does a Crankshaft or Camshaft Position Sensor Do?

The crankshaft position sensor monitors the crankshaft’s position and rotational speed, while the camshaft position sensor tracks the camshaft’s position. The engine computer uses information from both sensors to coordinate ignition and fuel-injection timing.

Because these components work together, a problem with either sensor can produce similar symptoms.

What are the Symptoms of a Bad Position Sensor?

Common warning signs can include:

• Hard Starting or No Start: A failing crankshaft sensor can prevent the engine computer from receiving the position information needed to properly coordinate ignition and fuel injection. A bad camshaft sensor can also cause extended cranking or a no-start condition in some vehicles.
• Engine Stalling: An intermittent sensor signal can cause the engine to stall while idling or driving. Unexpected stalling can create a safety concern and should be diagnosed promptly.
• Misfires or Rough Running: Incorrect position data can disrupt engine timing, resulting in misfires, rough idling, hesitation, or inconsistent performance.
• Poor Acceleration: You may notice sluggish response, hesitation, or reduced engine performance when accelerating.
• Reduced Fuel Economy: Incorrect timing or fueling can cause the engine to operate less efficiently, potentially reducing fuel economy.
• Check Engine Light: A sensor or related circuit problem may trigger the Check Engine Light and store a diagnostic trouble code.

Not every vehicle will experience all of these symptoms, and other engine problems can produce similar signs. A diagnostic test is the best way to identify the underlying cause.

Can You Drive With a Bad Position Sensor?

Driving with a suspected bad crankshaft or camshaft position sensor is not recommended if the vehicle is stalling, difficult to start, misfiring, or losing power. A sensor problem may cause the engine to shut off unexpectedly, potentially leaving you stranded or creating a hazard in traffic.

If the Check Engine Light is on but the vehicle is otherwise operating normally, have the issue diagnosed as soon as practical rather than assuming the sensor itself needs replacement.

What Causes Failure?

Position sensors can eventually fail from age, heat, moisture, oil contamination, damaged wiring, or connector problems. A damaged reluctor or timing-related component can also create symptoms or trouble codes that resemble a sensor failure.

This is why replacing the sensor immediately isn’t always the right first step. The sensor, wiring, connectors, and related timing components should be inspected before determining the repair.

How Is a Bad Position Sensor Diagnosed?

Technicians can use an OBD-II scan tool to check stored trouble codes and monitor engine data. Common codes associated with crankshaft or camshaft position circuits include P0335 for a crankshaft position sensor circuit malfunction and P0340 for a camshaft position sensor circuit malfunction. Correlation codes such as P0016–P0019 can indicate a problem with the relationship between crankshaft and camshaft position signals.

A code does not automatically prove that the sensor itself has failed. Wiring, connectors, reluctor components, or mechanical timing problems can produce similar codes, so further testing may be necessary.

Cost To Replace Position Sensor

Replacing a position sensor typically costs a few hundred dollars, but the final price varies by vehicle, sensor location, parts, and labor. A vehicle-specific diagnosis is needed to identify the cause and provide an accurate repair estimate, so the ranges below should be treated as general cost estimates rather than a guaranteed quote.

• Crankshaft Position Sensor: About $230–$335
• Camshaft Position Sensor: About $225–$325

If you’re experiencing hard starting, stalling, misfires, or a Check Engine Light, have the issue diagnosed before replacing a sensor. Contact our service team at Five Star Ford Stone Mountain to identify the cause and determine the right repair.