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Dodge Neon Sx 2.0 Engine Check Light On with P0340 Code: Camshaft Position Sensor Issues and Symptoms

Model: Dodge Sx 2.0 Fault Code: P0340 Posted: 2013-05-01 14:35

My Dodge Neon Sx 2.0 (2005 model) runs smoothly for extended periods, but suddenly the engine check light activates followed by a loss of power. The vehicle will then appear to stall or lose responsiveness on the highway, though it eventually recovers and resumes normal operation. After stopping and restarting the car, it runs fine again with the check engine light remaining on. I've confirmed the fault code P0340 using the ignition key — this indicates a camshaft position sensor circuit issue. The problem recurs periodically, sometimes after weeks of normal use. The sensor does not appear to be failing intermittently; instead, it seems to function normally at times and then fail again. I've inspected all connections and found no loose wires or corrosion. A spark plug cap on one cylinder appeared loose, but once replaced, the engine misfired continuously. I'm concerned about safety — driving on highways with sudden power loss could be dangerous. While I understand that camshaft position sensors can fail over time, it's unusual for them to cycle between working and failing without a clear cause. I've also noticed that disconnecting the battery clears the check engine light temporarily, but the underlying issue persists. I'm seeking advice on whether this is typically a sensor failure or wiring harness problem — especially given the location near the EGR tube. Are aftermarket sensors reliable? Should I replace with an OEM part? What diagnostic steps should I take to confirm the root cause?

Related fault codes
P0340
Comments (9)
Anonymous 2013-05-01 15:51

This is a 2005 Dodge Neon Sx 2.0 (sold as Dodge SX2.0 in Canada). P0340 indicates a camshaft position sensor circuit fault. Start by unplugging the sensor, cleaning the connector, and inspecting for damaged wiring or chaffed insulation. The sensor is relatively inexpensive — consider replacing it rather than just reseating connections. If you're comfortable with electrical troubleshooting, having a digital multimeter (DVOM) would help verify continuity and voltage. Note: clearing the DTC via battery disconnection removes not only the code but also valuable freeze frame data and emission test records.

Anonymous 2013-05-01 16:47

Yes, it's a 2005 Dodge Neon Sx 2.0 (sold as SX2.0 in Canada). How difficult is the sensor replacement? Is it worth replacing with an OEM part or can I use a reliable aftermarket sensor? Any recommendations on where to source one?

Anonymous 2013-05-01 17:16

A dedicated OBD2 scanner is essential to identify whether the issue is open circuit, high voltage, short to ground, or signal faults. The camshaft position sensor is located at the rear of the cylinder head. Check for damaged wiring harnesses — especially near the EGR tube where connectors can become pinched or corroded. Common fault codes include: - (K7) 5V Supply Circuit Shorted to Ground - (K7) 5V Supply Circuit Open - (K44) CMP Signal Circuit Shorted to Ground - (K4) Sensor Ground Circuit Open These issues can stem from wiring damage or poor grounding. The sensor itself is typically bolt-on and accessible, but proper diagnosis requires checking the signal and power circuits.

Anonymous 2013-05-04 08:53

P0340 is very common on Neon models — most cases are due to a faulty camshaft position sensor. Occasionally, the issue stems from a damaged wiring harness at the sensor connector, especially if it's near or in contact with the EGR tube. I recommend using an OEM sensor like those from Wells or the dealer. Many aftermarket sensors are of poor quality and may fail prematurely.

Anonymous 2013-05-04 17:49

Thanks for the advice — I've just replaced the camshaft position sensor with an OEM unit. I also cleaned the sensor, which had a small amount of oil residue. While the resistance readings between sensors were similar, I'm unsure if that oil was the root cause. The most concerning aspect is losing all power while driving on highways — it could lead to serious safety risks.

Anonymous 2013-05-06 08:19

For hall-effect sensors like cam or crank position sensors, an ohm test is generally ineffective in diagnosing failure unless the sensor shows a complete open circuit. A proper voltage and signal check using a DVOM is far more reliable for detecting faults.

Anonymous 2013-05-06 08:54

The car runs normally for long stretches before suddenly losing power — the engine remains running but power drops significantly, causing it to slow down or stop. After shutting off and restarting, the vehicle resumes normal operation with the check engine light still illuminated. This pattern repeats over time.

Anonymous 2013-05-06 18:09

The symptoms you're describing — sudden loss of power followed by recovery — are more typical of a crankshaft position sensor issue than a camshaft sensor failure, though both can present similar signs. It's worth investigating the crank sensor as well to rule out this possibility.

Anonymous 2013-05-08 10:41

Thanks for that insight — very helpful!