Parts for your 2009 Nissan Serena-Camshaft sensor

2009 Nissan Serena Camshaft Sensor — What it does and how to look after it

Yes, the 2009 Nissan Serena (C25) is fitted with a camshaft position sensor. This is confirmed in Nissan’s C25 Serena Service Manual (EC/Engine Control section) where DTCs P0340/P0345 cover the Camshaft Position Sensor (PHASE), and in Nissan’s parts catalogues listing the sensor for MR20DE-equipped Serena models. Common genuine part references include the Nissan camshaft position sensor under 23731-EN20A for the MR20DE engine.

On the 2009 Serena, the camshaft sensor keeps the engine management on the same page as the camshafts. It tells the ECU exactly where the cam is in its rotation, so the car can fire the spark and inject fuel at the right moment and properly run the CVTC (variable valve timing). That means clean starts, smooth idle, good power, and better fuel economy. If the signal goes missing or messy, the ECU can lose phase information and the van may crank longer, misfire, or even stall.

It’s not a routine replacement item, but it’s smart to keep an eye on it during scheduled services—especially past 100,000 kilometres. A visual once-over for oil wicking into the connector, cracked wiring loom insulation, or a loose retaining bolt is worthwhile. Fresh, correct-grade engine oil also matters because varnish and sludge around the timing area can affect both CVTC operation and the sensor’s signal quality.

Typical giveaway signs of a crook cam sensor include:

• Hard starting when warm or intermittent no-start
• Rough idle, flat spots, or reduced power
• Higher fuel use and a Check Engine light (often P0340/P0345)
• Occasional stalling when coming to a stop

Replacement on the MR20DE is usually straightforward: it’s mounted at the cylinder head near the timing cover and held by a small bolt. Disconnect the battery, unclip the connector, swap the sensor, lightly oil the O-ring on the new unit, and refit. Don’t overtighten the bolt, follow the workshop manual torque spec. After replacement, clear any codes and road test, the ECU will typically relearn phasing on its own. Always confirm wiring integrity before blaming the sensor, as damaged looms can mimic a failed unit. Choosing a reputable OEM or OE-equivalent sensor helps avoid repeat faults and weird intermittent behaviour.

Popular questions about the 2009 Nissan Serena camshaft sensor

How can someone tell if the camshaft sensor is failing on a 2009 Serena?
They’ll usually notice longer cranking, rough idle, a flat feeling off the line, or sudden stalls. The Check Engine light may pop up with codes like P0340 or P0345. If symptoms are on-and-off with no obvious pattern, wiggling the connector and loom during a scan can uncover an intermittent wiring fault.

Is it OK to keep driving with a dodgy camshaft sensor?
It might still run using fallback strategies, but it can be hard to start, down on power, and may stall—hardly ideal for school runs or motorway merges. Driving like this can also mask other issues. Best bet is to diagnose and repair promptly.

What does replacement usually cost in Australia or New Zealand?
As a ballpark, quality aftermarket sensors often land around $80–$160, with genuine typically higher. Labour is commonly 0.5–1.0 hour. Add diagnostic time if fault-finding is needed. Prices vary by brand and workshop rates.