Where is the coolant temperature sensor on the Nissan Sunny FB15: photo, signs of malfunction and replacement

Coolant temperature sensor (DTOZH) on Nissan Sunny FB15 - a critical element of the engine management system, on which the correct operation of the ECU, the fuel mixture, and even starting the engine in cold weather depends. Many owners encounter problems: floating speed, difficult starting "hot" or a light coming on CHECK ENGINE - all this may indicate a malfunction of this particular sensor. But before replacing, you need to know exactly where it is located, how to check it, and what nuances to consider when dismantling.

In this article you will find detailed layout diagram of the DTOZH on Sunny FB15 with engines GA15DE And GA16DE, as well as step-by-step instructions for diagnosis and replacement. We will analyze common mistakes when installing a new sensor, tell you how to distinguish it from the temperature indicator sensor on the dashboard, and give recommendations for choosing analogues. If you are planning a DIY repair, there is everything here to avoid common problems and save money at a service station.

Where is the coolant temperature sensor on the Nissan Sunny FB15: photo and diagram

On Nissan Sunny FB15 (1990–1999) coolant temperature sensor installed in the thermostat housing or on the top of the cylinder block - depending on the engine modification. On most versions with motors GA15DE/GA16DE it is located to the right of the thermostat (in the direction of travel of the car), next to the pipe going to the radiator. The sensor has two-pin connector (usually green or black) and is screwed into the body using a thread.

To accurately identify it, pay attention to the following visual signs:

• 🔍 Two wire connector (most often green or black, less often gray). The temperature indicator sensor on the dashboard, on the contrary, has one wire.
• 📍 Location: on GA15DE — closer to the oil filter, on GA16DE - just above the thermostat.
• 🔧 carving: standard M12x1.25, but some versions may require an adapter.

For clarity, the location diagram is shown below (view from the battery side):

element	Location	Note
DTOZH (for ECU)	Thermostat housing/cylinder block top	Two-pin connector, next to the radiator hose
Temperature indicator sensor	Cylinder head (cylinder head)	One wire goes to the dashboard
Thermostat	Below the DTOZH, under the pipes	Lid with spring valve

⚠️ Attention: Do not confuse DTOZH with radiator fan sensor (if it is installed separately) - the latter is usually located on the lower radiator pipe and has a connector with 3-4 contacts.

Signs of a faulty DVT on a Nissan Sunny FB15: how to recognize the problem

A faulty coolant temperature sensor can manifest itself in different ways, but there is 5 Key Symptomsthat should alert you:

1. Floating speed at idle speed (especially after the engine has warmed up). The ECU receives incorrect data and adjusts the fuel mixture incorrectly.
2. Difficult to start "hot". The engine may stall or be cranked for a long time by the starter because the ECU “thinks” that the engine is cold.
3. Lamp CHECK ENGINE with errors P0115 (DTOZh circuit malfunction), P0116 (signal out of range) or P0117 (low signal level).
4. Engine overheating for no apparent reason (the fan does not turn on, the temperature arrow goes off scale).
5. Increased fuel consumption. The ECU enriches the mixture, "thinking" the engine is cold.

🔧 Diagnostic lifehack: If you have a scanner (for example, ELM327), check the parameter Engine Coolant Temperature (ECT) in real time. If the sensor is faulty, the readings will be:

• 🌡️ Always 0°C (open circuit).
• 🔥 Instant jump to 120–140°C at startup (short circuit).
• ❄️ Stuck on one value (e.g. 80°C regardless of actual temperature).

⚠️ Attention: If the sensor “lies” in the direction of lowering the temperature (shows 40–50°C when the engine is warm), the ECU will constantly enrich the mixture. This leads to pouring candles And rapid failure of the catalyst.

How to check the coolant temperature sensor on a Nissan Sunny FB15 with a multimeter

Checking the DTOZH takes 10–15 minutes and requires a minimum set of tools: a multimeter (in ohmmeter mode), a thermometer and a container of hot water. Algorithm of actions:

1. Remove the sensor from the car (disconnect the connector, unscrew it with a 19 or 21 key).
2. Prepare your test environment: Pour water into a kettle or saucepan, heat to boiling (100°C) and let cool, measuring the temperature with a thermometer.
3. Connect the multimeter to the sensor contacts in resistance measurement mode (Ω).
4. Compare readings with reference values (see table below).

Temperature (°C)	DTOZh resistance (Ohm)	Note
0 (ice)	7000–10000	Maximum resistance
20 (room)	2500–3000	Normal for a cold engine
80 (working)	270–380	Optimal range
100 (boiling)	170–200	Minimum resistance

🔍 What to do if the readings do not match?

• 📉 Resistance is higher than normal → break in the internal spiral of the sensor.
• 📈 Resistance below normal → short circuit inside the housing.
• ⚡ Readings jump → the connector is damaged or the contacts are oxidized.

Disconnect the negative terminal of the battery|Drain some of the coolant (if the sensor is screwed into the block)|Disconnect the connector without damaging the latch|Check the integrity of the wires from the sensor to the computer-->

Step-by-step instructions for replacing the coolant temperature sensor on a Nissan Sunny FB15

Replacing DTOZH with Sunny FB15 does not require special skills, but there is 3 critical momentsthat are often missed:

1. Coolant drain (not necessarily completely, but the level must be below the sensor).
2. Correct tightening torque (15–20 Nm) - overtightening leads to damage to the threads in the aluminum block.
3. Using sealant only on the thread (not on the contact part!).

🛠 Required tools:

• 🔧 Head or key for 19/21 (depending on the year of manufacture).
• 🔩 Screwdriver for connector lock.
• 🧴 Thread sealant (for example, Loctite 577).
• 🧤 Gloves (coolant is toxic!).

What happens if you don't drain the coolant before replacing it?

When unscrewing the sensor, liquid under pressure will spray out of the hole, which can lead to burns (if the engine is hot) or coolant entering the generator/electronics. In addition, after replacement, the air in the system will have to be “dispelled” for a long time.

Step-by-step algorithm:

1. Disconnect the battery (remove the negative terminal).
2. Drain the coolant to a level below the sensor (or completely if you plan to change the fluid).
3. Disconnect the connector from the sensor by pressing the latch.
4. Unscrew the sensor counterclockwise. If it doesn't work, spray it WD-40 and wait 5 minutes.
5. Install a new sensor, after applying sealant to the threads. Tighten to 15–20 Nm.
6. Connect the connector and add coolant to the level.
7. Warm up the engine and check for leaks.

Which coolant temperature sensor to choose for Nissan Sunny FB15: original vs analogues

Original sensor from Nissan has an article number 22630-4M000 (for GA15DE/GA16DE), but its price is often overpriced (from 1500 rubles). Fortunately, there are proven analogues:

Manufacturer	Article	Price (RUB)	Note
Nissan (original)	22630-4M000	1500–2200	100% compatibility guarantee
Denso	550301-0920	800–1200	Japanese quality, often installed on the assembly line
Bosch	0 280 130 017	600–900	Universal, fits many models
Hella	6PT 009 103-041	500–700	Budget option, but the quality is worse than the original

⚠️ Attention: When purchasing an analogue, pay attention to thread length - it must match the original (usually 20–25 mm). Sensors with shortened threads may not reach the coolant, which will lead to incorrect readings.

🔍 Where to buy? Optimal options:

• 🛒 Official dealers Nissan - guarantee of originality, but high price.
• 🌍 Online stores (Exist.ru, Autodoc) - a wide selection of analogues.
• 🏗️ Showdown — you can find a used sensor for 200–400 rubles, but the risk of defects is high.

Common mistakes when replacing DVT on a Nissan Sunny FB15 and how to avoid them

Even experienced car owners sometimes make mistakes that lead to repeated breakdowns or new problems. Here TOP-5 misses and how to prevent them:

1. Sensor re-stretching → crack in the cylinder block. Solution: use a torque wrench (max. 20 Nm).
2. Lack of sealant → coolant leakage. Solution: apply Loctite 577 or similar thread sealant.
3. Dirt getting into the hole → channel blockage, incorrect readings. Solution: Before installing a new sensor, clean the hole with compressed air.
4. Using incompatible coolant → sensor corrosion. Solution: for Sunny FB15 fits Nissan L248 or analogues (CoolStream A-110).
5. Incorrect connector connection → broken contacts. Solution: The latch should click.

💡

The most common mistake is not checking the sensor before replacing it. In 30% of cases, the problem lies not in the DTOZH itself, but in the wiring or ECU. Always diagnose the circuit with a multimeter!

🔧 How to check the DTOZH chain?

• 🔌 Food: on the connector (with the ignition on) there should be 5 V between the contacts.
• 🔄 Weight: check the resistance between the negative contact of the sensor and the body - it should be close to 0 Ohm.
• 📊 Signal: when the engine is warm, the voltage on the signal wire should drop from 3–4 V to 0.5–1 V.

FAQ: Frequently asked questions about the coolant temperature sensor on the Nissan Sunny FB15

Is it possible to drive with a faulty DVT?

Technically possible, but highly undesirable. The ECU will operate in emergency mode, enriching the mixture, which will lead to:

• ⚡ Increased fuel consumption (up to 20–30%).
• 🔥 Engine overheating (risk of jamming).
• 💥 Rapid wear of the catalyst and spark plugs.

If the sensor “dies” on the road, try to get to the service station without sudden acceleration or prolonged idling.

How to distinguish DTOZH from a temperature indicator sensor?

On Sunny FB15 installed two sensors:

• 🔧 DTOZH (for ECU): two-pin connector, goes to the control unit.
• 🌡️ Pointer sensor: single contact, goes to the dashboard.

They may look the same but they cannot be swapped - this will lead to incorrect operation of the engine.

What to do if the engine overheats after replacing the DTOZ?

The reasons may be as follows:

1. Air lock in the cooling system → you need to “drive” it by opening the expansion tank cap on a warm engine.
2. Faulty thermostat → check if it opens at 85–90°C.
3. Defective new sensor → check it with a multimeter (see section above).
4. Coolant leak → inspect the sensor installation site for leaks.

Is it possible to clean the old sensor instead of replacing it?

Cleaning is possible, but not always effective. If the problem is oxidized contacts, they can be cleaned with sandpaper. If the thermistor coil inside the sensor is damaged, cleaning will not help. To clean:

1. Wash the sensor in isopropyl alcohol (not in the water!).
2. Clean the contacts fine sandpaper (1000+ grit).
3. Blow with compressed air.

If after cleaning the resistance does not correspond to the norm (see table), the sensor must be replaced.

What error is displayed when the DTOZh malfunctions?

On Nissan Sunny FB15 The following codes appear most often:

• P0115 — faulty coolant temperature sensor circuit.
• P0116 — the sensor signal is outside the permissible range.
• P0117 — low signal level (break or short to ground).
• P0118 — high signal level (short to +5 V).

For accurate diagnosis, use a scanner (ELM327, Launch CReader) or contact a service station.