Nissan Almera N16 is a popular sedan, but as its owners age, they encounter problems with the engine management system. One of the most common malfunctions is failure camshaft position (CMP) sensor, which is responsible for synchronizing the operation of injectors and ignition. If you see errors P0340 or P0343, and the engine stalls or doesn’t start well - this sensor may be the culprit.

In this article you will find exact location of the camshaft sensor on Almera N16 with engines QG15DE And QG18DE, as well as step-by-step instructions for checking and replacing it. We will look at how to distinguish a CMP malfunction from problems with the crankshaft sensor, and give advice on choosing spare parts. No fuss - only specific data with photos, diagrams and error codes.

Where is the camshaft sensor on Nissan Almera N16: photo and diagram

On Nissan Almera N16 camshaft position sensor (CMP sensor) installed in top of the cylinder head, next to the first cylinder. It is easy to identify by its plastic connector with three wires (signal, power, ground) and fastening with one bolt.

The specific location depends on the engine type:

  • 🔧 QG15DE (1.5 l): sensor is located right (in the direction of travel) at the end of the cylinder head, above the camshaft toothed pulley. Access to it is open after removing the decorative engine cover.
  • 🔧 QG18DE (1.8 l): Similar location, but due to the larger engine size, the duct may need to be removed for convenience.

The photo below shows the sensor on QG15DE (red arrow) and its connector (yellow arrow):

Visual references:

  • 📍 Next to the sensor there is a wiring harness going to the ignition coils.
  • 📍 Mounting bolt - turnkey 10 mm.
  • 📍 The sensor body is usually marked 23731-4M200 or similar (for original spare parts Nissan).
📊 What engine does your Almera N16 have?
  • QG15DE (1.5 l)
  • QG18DE (1.8 l)
  • Other
  • I don't know

Symptoms of a Malfunctioning Camshaft Sensor

Faulty CMP sensor manifests itself in different ways, but there is 5 Key Symptomsthat should alert you:

  1. Errors P0340 or P0343 - the most obvious sign. P0340 means a complete absence of signal, and P0343 — signal level is too high (often due to a short circuit).
  2. Poor engine starting, especially when it’s hot. The starter turns, but the engine does not “catch” or starts only after several attempts.
  3. Dips during acceleration and unstable idle speed. The ECU goes into emergency mode using data only from the crankshaft sensor.
  4. Increased fuel consumption (by 10–15%) due to incorrect injection.
  5. "Check Engine" light comes on with errors in valve timing.

⚠️ Attention: The same symptoms can cause crankshaft sensor (CKP), broken timing belt or ECU malfunction. Before replacing the CMP, be sure to check:

  • 🔌 Condition of the sensor connector (oxidation, wire breaks).
  • 🔧 The integrity of the toothed disc on the camshaft (sometimes the teeth get knocked together).
  • 📊 The presence of other errors in the ECU memory (for example, P0335 — crankshaft sensor).
💡

If the error P0340 appears only on a cold engine, the problem may be in the oxidized contacts of the connector. Try to clear them WD-40 and check again.

How to check the camshaft sensor on Almera N16 with a multimeter

Sensor check CMP takes 10–15 minutes and requires a minimum set of tools: a multimeter (in voltmeter and ohmmeter mode) and a screwdriver. Algorithm of actions:

  1. Removing the sensor:
    • Disconnect the negative terminal of the battery.
    • Press the latch and disconnect the sensor connector.
    • Unscrew the fastening bolt (wrench on 10 mm) and remove the sensor.
  • Resistance test:

    Connect the multimeter probes to the sensor terminals (polarity is not important). The resistance of a working sensor should be within the range 550–750 Ohm. If the readings tend to 0 (short circuit) or ∞ (break) - the sensor is faulty.

  • Voltage check:

    Set the multimeter to mode DC 20V. Connect the red probe to the signal wire (usually the middle pin), the black one to ground. When the camshaft rotates (can be cranked with a starter), the voltage should fluctuate in the range 0.3–4.7 V. Lack of change is a sign of a malfunction.

    • ⚠️ Attention: On some sensors Nissan The signal wire can be shielded. If, when checking the voltage, the readings “float” even without rotating the shaft, this is a sign of damage to the shielding braid.

    Disconnect the battery|Remove the sensor connector|Check the resistance (550–750 ohms)|Check the cranking voltage (0.3–4.7 V)|Inspect the camshaft toothed disc-->

    Step-by-step replacement of the camshaft sensor on Nissan Almera N16

    Replacing the sensor CMP on Almera N16 does not require special skills, but there are nuances that will help you avoid mistakes. The complete process takes about 30 minutes.

    Required tools and spare parts

    Name Article (original/analogue) Note
    Camshaft sensor 23731-4M200 (original)
    SMP CAM-106 (analog)    		 For QG15DE/QG18DE
    O-ring 13270-4M000 Comes complete with original sensor
    10 mm wrench — Socket or open-end wrench
    Flat blade screwdriver — To remove the connector lock

    Replacement instructions

    1. Preparation:

      Disconnect the negative terminal of the battery. Remove the decorative engine cover (if equipped) and the air duct to access the sensor.

    2. Removing the old sensor:

      Squeeze the plastic connector retainer and disconnect the connector. Unscrew the fastening bolt (the key is on 10 mm) and carefully remove the sensor. Be careful - there may be an O-ring left inside.

    3. Installing a new sensor:

      Check the integrity of the O-ring on the new sensor. Insert the sensor into the seat until it stops and tighten the bolt to a torque 8–10 Nm (do not overtighten!). Connect the connector.

    4. Check:

      Connect the battery and start the engine. If the error P0340 disappeared, and the engine runs smoothly - the replacement was successful. If the error persists, check the wiring or ECU.

    What happens if a faulty CMP sensor is not replaced?

    Driving for a long time with a faulty camshaft sensor leads to:

    1. Damage to the catalyst due to incorrect fuel mixture.

    2. Accelerated wear of spark plugs and coils.

    3. Engine overheating due to violation of valve timing.

    4. ECU failure (in rare cases) due to persistent errors.

    Mistakes when replacing a sensor and how to avoid them

    Even a simple sensor replacement CMP can lead to new problems if you make new mistakes. Here TOP-5 misses and how to prevent them:

    • 🔧 Damage to the O-ring. If the ring remains in the seat or breaks during installation, the sensor will not fit tightly, which will lead to oil penetration and repeated failure. Solution: Always check the integrity of the ring and lubricate it with engine oil before installation.
    • 🔧 Retightening the mounting bolt. Excessive force may deform the sensor housing or strip the threads in the cylinder head. Solution: Tighten the bolt to torque 8–10 Nm (use a torque wrench).
    • 🔧 Connect the connector before fixing the sensor. If the sensor is not fully inserted into the seat, the connector may deform its housing. Solution: First fix the sensor with a bolt, then connect the connector.
    • 🔧 Ignoring ECU errors. If after replacing the sensor the error P0340 remains, the problem may be in the wiring or the ECU itself. Solution: Ring the wires from the sensor to the ECU (contacts 24 And 47 on the ECU connector).
    • 🔧 Buying a low-quality analogue. Cheap sensors (for example, unnamed Chinese ones) often fail after 10–20 thousand km. Solution: Choose trusted brands: SMP, Bosch, Denso or original Nissan.
    💡

    If after replacing the sensor the engine starts only after 2-3 attempts, check gap between sensor and toothed disk. He must be 0.5–1.5 mm. If necessary, place a washer.

    How to distinguish a faulty camshaft sensor from a crankshaft sensor

    Symptoms of malfunction crankshaft sensor (CKP) And camshaft sensor (CMP) are often the same, but there are key differences that will help make an accurate diagnosis.

    Sign Camshaft sensor (CMP) Crankshaft sensor (CKP)
    Starting the engine Difficult to start, especially when hot Doesn't start at all or starts and stalls immediately
    Errors in the ECU P0340, P0343 P0335, P0336
    Idle behavior Floating speed, dips The engine stalls or runs extremely unstable
    Reaction to gas Difficulties during acceleration, loss of power The engine “does not pull”, twitches

    🔍 How to accurately determine the culprit?

    1. Treat errors as a scanner. If there is only P0340 - the problem is in the CMP. If P0335 — in CKP. If both errors occur, check both sensors.
    2. Check for spark. With a faulty CKP there will be no spark at all, with a faulty CMP there is a spark, but it is unstable.
    3. Inspect the toothed discs. On the CKP the disc is located on the crankshaft (under the flywheel), on the CMP it is located on the camshaft (under the cylinder head cover).

    FAQ: Frequently asked questions about the camshaft sensor on Nissan Almera N16

    Is it possible to drive with a faulty camshaft sensor?

    Technically possible, but not recommended. The ECU goes into limp mode using only data from the crankshaft sensor, which leads to:

    • Increased fuel consumption (up to +20%).
    • Loss of power (especially at high speeds).
    • Risk of catalyst damage due to incorrect fuel mixture.

    If the sensor fails completely, the engine may suddenly stall.

    Which camshaft sensor is better to choose for Almera N16: original or analogue?

    Original sensor (23731-4M200) reliable, but expensive (from 3000 rubles). Good analogues:

    • SMP CAM-106 — the best option in terms of price/quality (about 1,500 rubles).
    • Bosch 0 261 210 115 - high quality, but may not fit the connector (check before purchasing).
    • Denso 550-0104 - reliable, but rarely found on sale.

    🚫 Avoid sensors without a brand or with a suspiciously low price (less than 800 rubles) - they often fail after 5-10 thousand km.

    Do I need to reset errors after replacing the sensor?

    Yes, but not right away. After replacement:

    1. Start the engine and let it run for 2-3 minutes.
    2. If the error P0340 has not disappeared, reset it with a scanner or by disconnecting the battery for 10 minutes.
    3. If the error appears again, check the wiring or ECU.

    ⚠️ Do not reset errors before replacing the sensor - this will complicate diagnostics!

    Is it possible to check the camshaft sensor without a multimeter?

    Yes, but with restrictions. Alternative methods:

    • Replace with a known good one. Borrow a sensor from a friend or buy a used one in good condition.
    • Visual inspection. Check the sensor for cracks, contact corrosion, or traces of oil (indicates seal damage).
    • Checking with an oscilloscope. The services use an oscilloscope to analyze the signal - this is more accurate than a multimeter.

    Without tools, you can only indirectly judge the malfunction by symptoms (poor startup, errors).

    What should I do if the P0340 error remains after replacing the sensor?

    The reasons may be as follows (check in order):

    1. Wiring. Ring the wires from the sensor to the ECU (contacts 24 And 47 on the ECU connector). Look for opens or shorts.
    2. ECU. The control unit may be faulty (check by replacing it with a known working one).
    3. Camshaft toothed disc. If the teeth are chipped or the disc has turned, the sensor will not read the signal.
    4. Incorrect installation. Make sure that the sensor is inserted all the way and that the O-ring is intact.

    If the problem is not resolved, contact a diagnostician with an oscilloscope.