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2003 Chrysler 300M P0016 and P0340 Fault: Hard Starting in Cold Weather, RPM Limitation at 4000 RPM

Model: 2003 Chrysler 300M Fault Code: P0016 Posted: 2014-04-01 20:57

My 2003 Chrysler 300M experiences difficulty starting when cold. The engine cranks for 5 to 10 seconds before finally starting, but only under cold conditions. Once running, it operates normally until the next cold start. Diagnostic trouble codes P0016 and P0340 appear intermittently—sometimes both, sometimes just one. I replaced the camshaft position sensor and cleared the codes, but the issue persists. The check engine light remained off for about a week before returning with the same codes. When the light comes back on, the engine briefly stumbles and cuts out before running smoothly again. After replacing the cam sensor with an OEM unit (and also installing a new crankshaft position sensor), I still experience a critical issue: the engine will not exceed 4000 RPM in park. It runs normally up to around 3800 RPM, then stalls or becomes erratic when attempting to go higher. When the cam sensor is unplugged, P0340 returns immediately—clearing it resolves the code, but the problem remains. This suggests the sensor may not be the root cause. I've done some research and now believe the issue might relate to a rev limiter in the engine control module (ECM). Since there's no load on the engine when parked, the ECM may intentionally limit RPMs to prevent over-revving—especially under idle or park conditions. This could explain why the engine refuses to go beyond 4000 RPM despite normal operation at lower speeds. I'm seeking confirmation: is this a known behavior in 2003 Chrysler 300M models with P0340 and P0016 codes? Could the rev limiter be the actual cause, or are there other underlying mechanical or sensor-related issues I should investigate?

Related fault codes

P0016P0340

Comments (7)

Anonymous 2014-04-02 05:55

Did you use an OEM camshaft position sensor or an aftermarket one? Check the wiring harness and connector for corrosion or damage. Perform a 'wiggle test' on the sensor wires to ensure secure connections.

Anonymous 2014-04-02 08:40

Aftermarket sensor

Anonymous 2014-04-02 21:58

What are the common issues with aftermarket camshaft sensors?

Anonymous 2014-04-03 06:13

Aftermarket sensors are typically designed for multiple vehicle models and applications. Their calibration parameters often don't match those required by specific vehicles like the 2003 Chrysler 300M. Even if they function initially, mismatched readings can lead to recurring codes such as P0016 or P0340. Many professionals recommend OEM sensors because of consistent performance and compatibility—especially in older models where sensor tolerances are critical. In many cases, you're left with a persistent code simply because the sensor isn't properly calibrated for your vehicle. It's often cheaper to pay more upfront for reliability.

Anonymous 2014-04-03 07:42

Thank you for the insight—this helps clarify my troubleshooting path.

Anonymous 2014-04-04 19:15

Updated symptom: The engine will not exceed 4000 RPM in park. It starts with a miss and runs erratically until about 3800 RPM, then stalls or behaves oddly when trying to go higher. I replaced the camshaft sensor with an OEM unit and checked the crankshaft sensor—no codes after replacement. However, if I unplug the cam sensor, P0340 returns immediately. After clearing it, the code stays off, suggesting the sensor is not faulty. Any advice would be greatly appreciated. — Bob (P.S.: Both cam and crank sensors are OEM.)

Anonymous 2014-04-04 19:38

After some research, I believe this may be related to a built-in rev limiter in the ECM. Since there's no load on the engine when parked, the computer restricts RPM to prevent over-revving—especially under idle or park conditions. This could explain why the engine refuses to go beyond 4000 RPM despite normal operation at lower speeds. It may not be a sensor issue after all.