Understand and fix P0339: Crankshaft Position Sensor A Circuit High Input

Definition of P0339

P0339 is an OBD-II trouble code that’s triggered when your vehicle’s Engine Control Module (ECM) detects a problem with the ‘A’ circuit of the Crankshaft Position Sensor.

In plain English, it signals a disruption or irregularity with a key component monitoring your engine’s speed and rotation.

The Role of the Crankshaft Position Sensor

Imagine you’re trying to juggle. You need to know where the balls are at all times to keep them in the air. The Crankshaft Position Sensor serves a similar purpose for your engine.

It keeps tabs on the crankshaft’s speed and position, providing essential data to the ECM. This helps manage fuel injection and ignition timing, crucial for efficient engine operation.

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What ‘Circuit High Input’ Means

‘Circuit High Input’ might sound like tech-jargon but think of it as a tap with too much water pressure – it’s more than the system is designed to handle.

In this context, it refers to an overly high voltage signal received by the ECM from the crankshaft position sensor.

Causes of P0339 Error Code

Damaged Crankshaft Sensor

The most common culprit behind P0339 is a faulty crankshaft position sensor. Just like a worn-out juggler can’t keep the balls in the air, a damaged sensor can’t provide accurate data, causing a disruption in engine management.

Faulty Electrical Connections

Sometimes, the problem isn’t the sensor itself but the wiring connected to it. Corrosion, wear, and tear, or poor connections can interrupt the signal between the sensor and the ECM, leading to the P0339 code.

Issues with the Engine Control Module

While less frequent, the ECM can also be the source of the issue. If the module misinterprets the sensor signals due to software glitches or hardware failure, it can trigger the P0339 code.

Symptoms of P0339 Error Code

Ignition and Starting Issues

Ever tried to start a conversation without knowing what to say?

That’s how your engine feels when it gets irregular data from the crankshaft position sensor. The ECM doesn’t know when to ignite the engine, leading to hard starting or no-start conditions.

Engine Misfire

Inconsistent sensor signals can throw off the ECM’s fuel injection and ignition timing, leading to engine misfires. This is like a drummer missing a beat – the engine loses its rhythm and efficiency.

Check Engine Light Activation

Your vehicle’s onboard diagnostic system is designed to light up the ‘Check Engine’ warning when it detects an issue like P0339. This is your car’s way of telling you that it needs attention.

Diagnosing P0339 Error Code

Diagnostic Tools

One way to diagnose the P0339 code is by using an OBD-II scanner, a tool that retrieves trouble codes from the vehicle’s ECM. It’s like a medical thermometer – it helps identify the issue, but doesn’t provide a comprehensive solution.

Professional Inspection

Since P0339 could be caused by various factors, it’s best to seek a professional diagnosis. An experienced mechanic can thoroughly inspect the system and pinpoint the exact issue, much like a detective solving a mystery.

Fixing P0339 Error Code

Replacing the Crankshaft Sensor

If the crankshaft sensor is damaged, replacement is typically the best course of action. It’s like replacing a faulty lightbulb – it restores the system’s functionality.

Repairing Electrical Issues

If the issue lies in the wiring or connections, repairing or replacing the faulty components can resolve the P0339 code. It’s akin to fixing a frayed charging cable for your phone.

Updating the Engine Control Module

In some cases, updating the software or replacing the ECM might be necessary, similar to updating your computer’s operating system to fix a persistent error.


Understanding and addressing the P0339 trouble code is crucial for maintaining your vehicle’s health. It’s akin to a physician diagnosing and treating a medical condition. By understanding the symptoms, possible causes, and solutions, you can ensure your vehicle remains in top shape and continues to serve you reliably.


1. Can I drive with the P0339 error code?

While it might be possible, it’s not recommended due to potential engine misfires or even failure. Think of it like playing with a sprained ankle – you might manage for a bit, but it could worsen the injury.

2. How much does it cost to fix a P0339 code?

The cost varies depending on the issue’s root cause. Imagine having a leaky faucet – it could be a cheap washer replacement, or you might need a new tap entirely.

3. Is a P0339 code serious?

Yes, it can lead to poor vehicle performance and potential engine damage if not addressed. Think of it as a fever – it’s a symptom of an underlying condition that needs attention.