In winter or after a long period of inactivity Renault Logan 2 may fail: the engine cranks with difficulty, the starter turns sluggishly, and sometimes even refuses to start. If your car has trouble starting when cold, this does not always mean a serious breakdown - often the problem lies in small things that you can fix yourself. However, the symptom cannot be ignored: over time, the malfunction progresses, and repairs are more expensive.

In this article we will look at 7 main reasonswhy Logan 2 (including modifications with engines K7M, K4M and H4M) does not start well when cold, and we will also give step by step instructions for diagnosing and troubleshooting. From simple checks (battery, spark plugs) to complex ones (sensors, fuel system), you will learn where to start and when to call for service.

We will pay special attention the specifics of Renault gasoline engines, where the problem is often related to the operation of the throttle valve and coolant temperature sensor. We will also consider cases when it is not the engine that is to blame, but the electronics - for example, the immobilizer or control unit.

1. Discharged or faulty battery

The most obvious reason for a difficult startup is weak battery. When the battery is cold, it loses up to 30% of its capacity, and the starter requires more energy to turn over the thickened oil. If you hear relay clicks when you turn the key or the starter barely turns, the battery is to blame.

How to check:

  • 🔋 Terminal voltage no load: should be 12.6–12.9 V. If below 12.4 V - battery low, below 11.9 V - deep discharge.
  • 🔧 Electrolyte density (for serviced batteries): normal 1.27–1.29 g/cm³. If below 1.25 - requires charging.
  • 🔌 Leakage current: disconnect all consumers, remove the negative terminal and connect an ammeter. Norm - up to 50 mA.

If the battery is old (more than 4-5 years), its capacity could drop critically. In this case, even after charging the problem will return. The solution is to replace it with a new battery with the following parameters:

Parameter Recommended value for Renault Logan 2
Capacity 60–70 Ah
Starting current (EN) 540–600 A
Polarity Reverse (0)
Dimensions (L×W×H) 242×175×190 mm
⚠️ Attention: If the problem persists after replacing the battery, check generator. A faulty alternator does not charge the battery during a trip, and it quickly runs out. Signs: dim headlights, flashing battery light on the dashboard.

2. Problems with the starter or solenoid relay

If the battery is ok but the starter turns tight or doesn't work, the problem may be in himself. On Logan 2 The brushes often wear out, the contacts of the solenoid relay burn out, or the bendix jams.

How to diagnose:

  • 🔊 Characteristic sound: click without rotation - the solenoid relay is faulty; The grinding noise is wear on the bendix.
  • 🔧 Voltage check: Connect a voltmeter to the terminal 50 solenoid relay. When turning the key there should be 12 V.
  • 🛠️ Visual inspection: remove the starter and check the wear of the brushes (length less 5 mm - replacement required).

On Renault Logan 2 with engine K4M (1.6 l) the starter often “dies” after 150–200 thousand km. If it has already been repaired, it is cheaper to replace it entirely. Average cost of a new starter - 8–12 thousand rubles., used - 3–5 thousand rubles..

📊 How often do you check the starter?
Once a year
Only in case of breakdown
Never checked
I repair it myself

3. Faulty spark plugs or high voltage wires

Worn spark plugs or broken wires lead to misfires, especially when cold, when the fuel mixture ignites less easily. On Logan 2 recommended spark plug replacement interval - 30 thousand km (regular) or 90 thousand km (iridium).

Signs of malfunction:

  • ⚡ Engine tripping after launch.
  • 🔥 Black soot on the spark plug electrodes (rich mixture) or white (lean mixture).
  • 📉 Power drop and increased fuel consumption.

How to check:

  1. Unscrew the spark plugs and inspect the gap: the norm is for Renault Logan 2 — 0.9–1.1 mm.
  2. Check the resistance of the high-voltage wires: it should be within 3–10 kOhm (depending on length).
  3. Start the engine in the dark: if visible sparks on the wires, they need to be replaced.

For Logan 2 suitable candles: NGK (BKR6E), Bosch (FR7DCX), Denso (K20PR-U11). The cost of the set is from 800 rub..

Unscrew all spark plugs (use a 16 mm wrench)

Inspect carbon deposits and clearance (normal 0.9–1.1 mm)

Check the resistance of high-voltage wires with a multimeter

Replace the spark plugs as a set (even if one is faulty) -->

4. Dirty throttle body or faulty idle speed sensor

On Renault Logan 2 with engines K7M/K4M the throttle valve often gets dirty oil coating from the crankcase ventilation system. This leads to:

  • 🌀 Unstable speed to cold.
  • 🚗 Difficulty starting (the engine catches speed and stalls).
  • ⚠️ Check Engine with an error P0505 (idling system malfunction).

How to clean the throttle:

  1. Remove the air duct pipe and unscrew the throttle assembly (4 bolts).
  2. Wash the valve and channels carburetor cleaner (for example, LIQUI MOLY Pro-Line Drosselklappen-Reiniger).
  3. Be sure to clean throttle position sensor (DPDZ).
  4. After installation, run throttle adaptation:
1. Turn on the ignition for 10 seconds.

2. Turn off, wait 10 seconds.


3. Start the engine and let it idle for 2-3 minutes.

If the problem persists after cleaning, check Idle air regulator (IAC). On Logan 2 it often fails after 100 thousand km. The cost of a new one is approx. 1.5 thousand rub..

5. Problems with the fuel system

If the engine doesn't grasp or starts only after a long rotation of the starter, the fuel system is to blame. On Renault Logan 2 typical problems:

  • 🛢️ Clogged injectors (especially if you refuel at dubious gas stations).
  • ⚙️ Faulty fuel pump (low pressure in the ramp).
  • 🔥 Air leak through cracked hoses or gaskets.

How to diagnose:

Symptom Possible reason Solution
The engine does not start, the starter turns No pressure in the fuel rail Check the pump fuse (F3, 15 A), relay (K5), pressure with a pressure gauge (standard: 3.5–4 bar)
The engine shakes and jerks Injectors clogged Washing with ultrasound or liquid (Wynn's Injection System Purge)
Smell of gasoline in the cabin Fuel leak or air leak Inspect the hoses and clamps, check the ramp gasket

On Logan 2 with engine H4M (1.6 l, 16 valves) often fails fuel pressure sensor. Replacing it costs 2–3 thousand rubles..

⚠️ Attention: If the problem remains after flushing the injectors, check compression in cylinders. Low compression (below 10 bar) indicates wear on the piston rings or valves.

6. Sensor malfunctions: DTOZH, mass air flow sensor, lambda probe

Electronic sensors directly affect engine starting. If they produce incorrect data, the ECU (Electronic Control Unit) incorrectly prepares the fuel mixture. On Renault Logan 2 Most often they fail:

  • 🌡️ Coolant temperature sensor (DTOZH): if he is lying, the ECU “thinks” that the engine is hot and delivers a lean mixture.
  • 💨 Mass air flow sensor (MAF): Contamination or damage leads to incorrect load calculation.
  • 🔄 Lambda probe: affects the mixture, but usually appears after warming up.

How to check DTOZH:

  1. Remove the connector from the sensor (located on the thermostat).
  2. Measure the resistance between the contacts at different temperatures:
Temperature (°C) Resistance (kOhm)
0 (ice) 7–9
20 (room) 2.5–3
80 (hot engine) 0.3–0.5

If the values do not correspond to the norm, the sensor must be replaced. The cost of a new DTOZH for Logan 2 - about 500 rub..

How to deceive the ECU if the DTOZH breaks down on the road?

If the temperature sensor fails and you need to drive urgently, you can temporarily disconnect its connector. The ECU will go into emergency mode and use a fixed temperature value (usually 20°C). The engine will run worse, but you will get to the service station.

7. Problems with the immobilizer or alarm

If Renault Logan 2 won't start, but the starter turns, but there is fuel and a spark, it could be the culprit immobilizer system. On these cars, the communication between the key, immobilizer and ECU often fails.

Signs:

  • 🔑 The immobilizer lamp is flashing (yellow key on the panel).
  • 🚫 Engine stalls after 3–5 seconds after launch.
  • 📛 Error U1000 or DF006 during diagnosis.

How to fix:

  1. Try it second key — if it starts, the problem is in the chip of the first one.
  2. Reset errors by disconnecting the battery for 10 minutes.
  3. If it doesn't help, you need to immobilizer flashing or replacing the antenna around the ignition switch.

On Logan 2 with alarm StarLine or Pandora the problem may be ignition lock. Check to see if auto-start works when you turn the key.

💡

If the immobilizer has blocked the engine and there is no spare key, you can temporarily disable it by closing the contacts 1 and 2 in the antenna connector. But this will only work on older versions of the ECU. Siemens SID301 (until 2014).

FAQ: Frequently asked questions about launching Renault Logan 2 when cold

Is it possible to start Logan 2 from the pushrod if the starter does not turn?

Yes, but only on a manual transmission. Algorithm:

  1. Turn on the ignition.
  2. Depress the clutch and turn on 2nd gear.
  3. Accelerate the car to 10–15 km/h and slowly release the clutch.

⚠️ Do not try it on injection engines with automatic transmission - it will damage the gearbox!

How often should you change your oil to avoid cold starting problems?

For Renault Logan 2 recommended interval - 15 thousand km or once a year. But if the car is operated in difficult conditions (short trips, frost), reduce the interval to 10 thousand km. Use oil with viscosity 5W-40 or 5W-30 (for example, Elf Evolution 900 NF).

Why does Logan 2 start only with the gas pedal pressed?

This is a sign:

  • Polluted throttle assembly.
  • faulty Mass air flow sensor or DTOZH.
  • Air leak through cracked pipe after the flow meter.

Start by cleaning the throttle body and checking the sensors.

How much does a service diagnostic cost if I can’t find the cause myself?

Diagnostic cost Renault Logan 2 in the service:

  • Computer diagnostics (reading errors) - 800–1500 rub.
  • Checking the fuel system — 1000–2000 rub.
  • Comprehensive diagnostics (engine + electronics) — 2500–4000 rub.
Can bad gasoline cause difficult starting?

Yes! If you refuel with low-quality fuel, you may:

  • The injectors are clogged.
  • The fuel pump fails (due to impurities).
  • The catalyst will be damaged (if there is a lot of sulfur in gasoline).

Solution: drain the bad gasoline, flush the fuel system, replace the filter.