There are many answers to one of the most popular questions on car Internet forums. Of course, without being able to diagnose or at least visually inspect the car, it is often impossible to get to the bottom of the problem and identify its cause. However, malfunctions due to which Renault may not start can be roughly divided into several categories depending on the "symptoms":

Doesn't turn the starter:

Battery does not supply sufficient voltage

This can usually be understood by the dashboard dying out during an attempt to start, or when there is no power to all the car's devices at all. Solved by replacing or charging the battery;

Open circuit of the starter power supply

There are times when the wiring from the control unit to the starter is damaged, or there is poor contact at the terminals of the starter solenoid relay. To solve the problem, wiring repair or cleaning / tightening the terminals is required;

Starter defective

After making sure that the starter power is normal, you can come to the conclusion that the starter itself is damaged. In this case, repair or overhaul (cleaning / lubrication) of the starter is required;

the starter motor may not be powered. This can be due to both a blown fuse and a serious breakdown of the car's electronic system. If the fuse has nothing to do with it, it is better to contact a qualified service;

Engine jammed

The most “sad” of the possible options is when the starter does not turn simply because it cannot turn the crankshaft due to a mechanical engine failure. Usually solved by overhauling or replacing the engine (or cylinder head);

Fuel does not flow:

The fuel in the tank has run out

If the fuel level sensor fails, it can mislead the driver by showing a sufficient fuel level when it is actually absent.

Solved by refueling;

Damaged fuel line

It happens especially after driving off-road. The fuel pipe can be ripped off or broken. In this case, fuel flows out without reaching the injectors. Solved by replacing or repairing the damaged part;

Fuel injectors do not work(for gasoline engines)

Usually associated with a lack of power to the injectors from the control unit, since it is practically unrealistic for all fuel injectors to fail at the same time. May require repair or replacement of the engine control unit (“brains”);

Fuel pump is not powered(for gasoline engines)

As in the case of a lack of power to the starter, it can be solved by replacing the fuse. Otherwise, qualified diagnostics by the scanner is required;

Fuel pump defective(for gasoline engines)

No spark:

Ignition module (coil) does not work

Spark plugs require replacement (cleaning)

Malfunction of one of the sensors responsible for the correct operation of the engine or engine control unit

Electrical sensors transmitting parameters to the engine control unit can directly affect the start of the car, namely, block the spark or fuel supply when trying to start. The problem requires a competent diagnosis with a scanner;

Violations in the intake or exhaust systems of the engine:

Intake tract problems

Due to worn intake manifold or throttle gaskets, as well as general contamination of components such as the throttle valve, idle speed regulator, gas recirculation valve, etc. - starting the engine may be difficult or impossible. It is solved by cleaning the listed parts and replacing the necessary gaskets with new ones, after which it may be necessary to reset the adaptive settings of the ECU with a scanner;

Clogged catalyst

If the catalyst has collapsed and clogged the exhaust pipe, the engine may not start. the exhaust gases will have nowhere to go. In this case, the catalyst is removed from the exhaust system and either changed to a new one (which is very expensive), or the engine control unit is reflashed for operation without a catalyst;

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Asks: Mozart Valery.
Essence of the question: Renault Logan will not start on a cold one, but Renault Logan will not start on a hot one.

Bought Logan from a former owner, a Phase 1 car. The mileage is small, but recently a defect has appeared: when starting "cold" everything works, but when "hot start" the motor does not start. It turns out that you have to wait 5-6 minutes until the engine cools down. The starter turns, but the motor does not pick up. This was not the case before.

Still, why doesn't my Renault Logan start as it should?

Main reasons

The reason for the defect indicated in the question may be one - a faulty DTOZH sensor. This sensor itself will need to be replaced, but one test can be done first.

Coolant temperature sensor

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I own a Renault Megan 2 car, before that there were Citroens and Peugeots. I work in the service area of \u200b\u200ba dealership, so I know the car's structure "inside and out." You can always ask me for advice.

So, we will simulate a problematic situation:

1. We start "cold", warm up the engine;
2. It is necessary to ensure that the motor stops starting. There is no need to wait 5 minutes;
3. If the engine cannot be started, open the hood and turn off the DTOZH sensor. Try to start up immediately.

Conclusions: if at "step 3" the motor starts up again, then the reason is in a faulty sensor. Further comments are unnecessary.

Another likely reason

The connector that causes problems

Disconnect the connector with the ignition off. Do not forget to collect everything as it was.

Line B8 in R212 is connected to the ignition switch. If it is broken, the starter will work, but the engine start is blocked.

Let's consider the reasons when Renault Logan does not start "on cold". They look trite:

• The battery is frozen or discharged;
• Water has entered the tank;
• Defective fuel pump;
• Etc.

But there is another reason, typical only for the Logan family.

Defect in the ECU program on an engine with Euro-3

If the engine complies with Euro-3 standards, then the ECU controller may need to be updated. At one time, a review was carried out, but not all responded to Renault's request.

The only "letter of happiness" from Renault

Logan sedans, which are subject to recall, were produced from December 2007 exactly before the restyling. We are talking about the transition to "phase 2" (to Euro-4 standards).

Renault Logan won't start? We ourselves check the DTOZH sensor - an example in the video

The situation when the car refuses to start or immediately stalls after starting is one of the most unpleasant surprises in the life of a car owner. What can be the cause of such problems with Renault Sandero Stepway and how to fix it, we will tell you in our today's article.

Starter does not work

Open circuit in the power supply. A power failure may be caused by poor contact at the battery terminals or damaged wiring from the starter to the control unit. Tightening the terminals and replacing damaged wiring will completely eliminate the problem.

Lack of battery voltage

A weak battery charge can be easily identified by the dimming instrument lighting during an attempt to start the engine. If the battery is completely discharged, the devices will not light up at all. In this case, it is enough to change the battery, charge the old one from another car, or connect it to a special charger. In stores, you can also find portable launchers that will come to the rescue away from home.

Electricity may not be supplied to the starter even after one of the fuses has blown. They are very inexpensive, but they can burn out due to a short circuit in the circuit. If the new fuse fails again, it is worth contacting a professional auto electrician.

Starter malfunction

If everything is in order with the starter power supply, but it does not respond to the turn of the key, the reason may be a breakdown of the mechanism itself. Cleaning, repair or replacement will be required.

Mechanical engine failure

This is perhaps the most negative scenario. In this case, the starter does not work simply because it is not able to turn the crankshaft. There is no simple solution here, the motor will have to be repaired or changed to a serviceable one, but in the beginning, in any case, you will need to make a thorough diagnosis.

Fuel does not flow

No matter how trite it may sound, but first of all it is worth checking whether the gasoline in the tank has run out. The fuel level sensor may well break down and display false information on the dashboard. However, this is a rather rare case.

Fuel pump has no power

As with the starter situation, checking the appropriate fuse and wiring will be required.

Fuel pump malfunction

The Sandero Stepway gasoline pump can fail for various reasons. For example, due to poor quality gasoline or overheating when working in an empty tank. The problem is solved by replacing the pump motor, or the entire structure as an assembly.

Damage to the fuel pipe

When driving off-road or simply on a poor surface with stones, there is a risk of damaging the fuel line. Gasoline in this case will flow to the ground and will not reach the engine. Repairing the damaged area will return the car to service.

Failure of fuel injectors

Since it is unlikely that all injectors will fail simultaneously, the problem is most likely in the engine control unit. It will need to be replaced or repaired.

Spark plug

The spark plugs can produce insufficient spark to start; cleaning the spark plugs or replacing them can remove the issue.

Ignition coil breakage

In addition to the failure of the module itself, the reason is often hidden in poor contact at the connector. The solution is to clean the contacts or replace the coil.

Problem with sensors

Numerous sensors that send information to the engine control unit sometimes do not work correctly. Here you need a competent specialist with special equipment for diagnostics.

Other common causes

Clogged exhaust pipe. If the destroyed catalyst clogs the exhaust pipe, the exhaust gases will have nowhere to go and the car will not start. In such a situation, the catalyst is removed from the exhaust system and either the engine is reconfigured to work without it, or a new one is installed.

Compression disorder. Compression in a combustion engine is its ability to maintain operating pressure in the combustion chamber. The parameter is measured with a special device. The presence of problems with compression is indicated by unstable idle speed, increased gasoline and oil consumption, and blue exhaust smoke.

Immobilizer problems. A dead battery in the ignition key will prevent the engine from starting, as well as a malfunction of the chip inside the key. You can use a spare key to check the version.

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In the article, we will consider possible malfunctions that may arise during the operation of a Renault / Dacia Sandero car.

The engine will not start

Starting the engine with the fuel injection system is the same at all ambient temperatures and the liquid in the engine cooling system.

To start the engine, you just need to turn on the starter without pressing the gas pedal, and the system will automatically adjust to the necessary parameters of fuel supply and ignition timing.

If the engine fails to start after three attempts:

Open the hood by pulling the drive handle towards you

We measure the oil level with a dipstick

In the K4M engine, the oil level should be between the upper and lower border of the shaded area

In the K7J and K7M engines - between the lower and upper marks on the dipstick

Checking the coolant level

It should be between the MIN and MAX marks on the expansion tank.

We examine the engine. Pay attention to the drips of gasoline, oil and coolant.

We check the integrity of the wiring.

We check the fit of the pads of the wiring harnesses in the connectors of the ignition coils.

After inspecting the engine and systems, we try to start the engine again.

If the engine does not start on the first attempt, then press the gas pedal all the way and turn on the starter for two to three seconds.

In this mode, the cylinders are purged, no fuel is supplied through the injectors and no voltage is supplied to the spark plugs.

After purging the cylinders, we try to start the engine in normal mode, without pressing the gas pedal.

If, nevertheless, the engine does not start, then:

The power supply system does not work;

The ignition system does not work;

The starting system does not work.

Start faults

Starter does not turn on.

This could be caused by broken contacts and connections.

Open or short circuit in the starter switching circuits, traction relay malfunction.

If clicks are heard when the starter is turned on, then the reason is in a discharged battery, oxidized or weak contacts on the battery or starter.

Also, the reason may be a malfunction of the holding winding of the traction relay.

If the starter turns on, but the armature either does not rotate or rotates slowly.

The reason is that the battery is discharged, the contact connections are broken, the contacts of the traction relay are burned, the collector is dirty or the brushes are worn out, interturn or short circuit in the starter windings.

If the starter is engaged, its armature rotates, but the flywheel is stationary.

The cause may be a weakening of the fastening of the starter to the clutch housing, damage to the teeth of the flywheel or drive gear, slipping of the drive freewheel clutch, breakage of the lever, drive ring or buffer spring of the starter drive.

If the starter does not turn off after starting the engine.

The reason is a malfunction of the starter freewheel clutch, sintering of the traction relay contacts. If such a malfunction occurs, the engine must be stopped immediately.