Error 1602 on VAZ 2114: reasons, explanation, how to fix it?

Modern cars are equipped with quite effective on-board controllers, which are able to identify and indicate a particular problem that has arisen in the main systems and components.

In the event of a breakdown, a specific code consisting of letters and numbers is displayed on the computer screen, confirming the presence of an error. In earlier models of the Volzhsky Automobile Plant, in this situation, a light flashes, prompting you to check the engine and one of the few main codes is displayed, even if the breakdown is insignificant. Modern ECUs are already capable of informing the owner about the nature of the problem with maximum accuracy.

In this article we will talk about what kind of malfunction in the VAZ-2114 should be suspected if error 1602 appears.

What does the error code mean?

Error P1602 is diagnosed on cars when one of the on-board voltages is not supplied to the engine control unit (ECU). Various options are possible: both permanent absence and short-term outages (one-time or periodic).

As a rule, the control unit receives voltage via several buses:

30 bus – on-board network voltage, which operates constantly, parallel to the positive terminal of the battery;
15 bus – on-board network voltage through the ignition switch (relay);
50 bus – on-board network voltage supplied when the “engine START” key is turned on.

In this case, the engine control unit can receive direct power from various contacts of the ECU connector. Thus, monitoring the voltages supplied to the engine control unit is difficult in the absence of a circuit diagram. Depending on which power supply is missing, the vehicle may behave differently with the same P1602 error.

The most characteristic symptoms:

the ignition does not turn on;
the ignition turns on, the starter does not start;
the ignition turns on, the starter operates when the engine starts, the engine does not start;
the ignition turns on, the engine starts, does not respond to the accelerator pedal or other controls;
the ignition is turned on, the engine starts, there is color music on the dashboard (indicator lights blink, dial gauges deviate chaotically);
The car is operating normally, the error is diagnosed.

Error P1602 does not necessarily indicate a complete lack of voltage at one of the power inputs. The battery may have been discharged to a critical level or was temporarily disconnected from the terminals. After connecting the battery, error P1602 remains in the memory of the control unit, and it is enough to delete it (erase from memory) for the engine ECU to exit the emergency mode.

Decoding P1602

Low voltage supply to the engine control unit (AUDI, ISUZU, SAAB, VOLKSWAGEN).
Knock Sensor Module Performance (BUICK, CADILLAC, CHEVROLET, GMC).
Speed Control Solenoid (DODGE) Circuit.
Problem with the wiring of the engine control unit (HYUNDAI, KIA).
Engine control unit immobilizer error (MAZDA).

Where is the P1602 sensor located?

The image above shows the ECU connector of an Audi Q7, terminal 30 is circled.

It should be noted that this code does not refer to the voltage at terminal #30 as shown here, but to the various and multiple terminals in the connector that should have a certain voltage across them when the ignition is turned off. Therefore, the presence or absence of power at terminal No. 30 (as shown here) when the ignition is turned OFF should NOT be taken as evidence of failure or malfunction unless the manual for the vehicle in question explicitly states that the specified voltage should or should not (depending on depending on the circumstances) be present at this terminal when the ignition is turned off.

Operating principles of the on-board computer

The electronic control unit of the VAZ 2114, as on other cars, is primarily designed to monitor the condition of various components and assemblies, as well as for subsequent indication of breakdowns if they occur. The introduction of the concept of self-diagnosis is a sound decision designed to facilitate both the operation of the car for the driver and possible repairs for the car service center.

The system works simply: if a unit breaks down or there is no signal from it, the ECU displays a coded message on a small display, which can be deciphered using the appropriate car manual.

Alas, as often happens with the domestic auto industry, the electronic brains of the ECU may begin to fail for one reason or another, giving the VAZ 2114 error 1602 in situations where there is no real breakdown. At the same time, the problem cannot be ignored under any circumstances, because once out of ten the control unit can signal that there are actually problems in the system.

Instead of immediately going to a service center and paying money for diagnostics, experts recommend trying to find out the cause of error 1602 on your own - it is quite possible that even an inexperienced car owner will be able to solve the problem.

It is important to remember that first of all, you should exclude the possibility of an error in the operation of the ECU itself and sensors if any error is detected on the screen. It will be useful to buy only original electronics parts in advance when operating a car, and not install cheap analogues (the same is true for unlicensed firmware).

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As for the general list of reasons that can alert the ECU with a problem message, the most common factors are:

Changing the type of fuel system without flashing the controller.
Low quality fuel, which has a complex effect on the entire energy system.
Clogged air or fuel filter.
Inept attempts to reconfigure the “brains” of the controller.
System failure of the ECU or failure of one of the sensors.

Do not forget that any intervention in the factory settings of the computer or replacement of sensors (as well as cables and connectors) with unofficial ones, not produced by AvtoVAZ, is fraught with frequent errors in the operation of the ECU - as a result, this means lost nerves and money in the future.

How to check the generator and replace the brushes on it

If you have tried all possible troubleshooting options on your VAZ-2114, but nothing worked, check the generator. To do this you will have to dismantle it:

Remove the negative terminal from the battery and disconnect the wire leading to the generator casing.
Remove the nuts from the upper and lower alternator mountings, then loosen the tension bolt and remove the alternator belt.
Remove the clamping bar.
Remove the generator along with the casing.

There are several ways to check the generator. One of them is to use a stand, but it is only available in car services. Ordinary car enthusiasts will have to disassemble the generator, check its coil with a multimeter and inspect the components. Particular attention should be paid to the brushes, which need to be replaced if necessary. Often a coil or bearing wears out its life, in which case you will need to purchase these components and install them in place of the failed ones.

Source

Possible reasons

When diagnosing error P1602, the engine control unit is insufficiently powered from the on-board network. What could be the reasons:

temporary disconnection of the battery terminals (terminals) from the on-board network for the period of repair or maintenance;
critically low battery charge;
voltage dips in the on-board network during engine startup with low residual battery capacity (for example, during engine startup at extremely low ambient temperatures);
fuse blown in the power supply circuit;
fraying of contacts or malfunction of relays servicing the engine control unit;
contact failure of the control unit connector;
abnormal operation of car alarms;
error on the CAN bus (communication bus between control systems);
problems with the generator;
violation of the common wire (ground) of the car;
control unit malfunction;
previous polarity reversal when installing the battery.

The intellectual capabilities of such a computer

Even though the on-board computer for the Lada Priora does not have any special brains, the device can significantly make life easier for the car owner. Each manufacturer has its own characteristics and features, so anyone can choose an assistant to suit their taste. Various displays, functions, controls, designs. What benefits can this device provide?

Monitoring and controlling vehicle sensors.
Quite long battery life.
Displays the quality of fuel entering the gas tank.
Monitoring the temperature of antifreeze and the ability to control the cooling system.
Engine speed sensors.
When the gas system is installed, the computer can switch the “gas/gasoline” mode.
Many different diagnostic protocols.
Control of parking radars and headlight modes.
Built-in tachometer, external and engine temperature sensor, econometer and other amenities.

Error 1602 on VAZ cars: what is the reason

If you look through the VAZ manuals that came with the car, you will find information in them that this malfunction can only occur under the following conditions:

With the ignition off;
If the controller notices that some data has been lost.

This problem occurs on almost all relatively new VAZ models, for example:

Priora;
Grant;
VAZ 2110;
VAZ 2112;
VAZ 2114;
Kalina;
Niva Chevrolet;

It’s difficult for me to immediately see all the reasons for error P1602. I will try to talk about the main ones. I will describe the problem using the example of individual units in which an error can most often occur:

Battery. It may be discharged or you have poor terminal contact. I once had a problem due to a large number of electrical appliances (I connected an electric winch and plugged in a few more lamps). The system couldn't cope. Also, P1602 may appear if you change the battery or when starting the engine on a discharged battery.
Generator. The reason may be its power or the fact that the contact disappears. The problem often occurs on Priors, Kalinas and VAZ 2114

Signaling. There are modern car protection systems that turn off the battery when the alarm is turned on. It is assumed that if thieves get into the cabin, they will not start the engine. However, the system may generate this exact error.
Minor power loss. For example, you start your car in cold weather. A large flow of energy went from the battery to the starter. The controller was left without power for a short time. As a result, the system issued P1602.
“Mass” of the controller. The reason is quite common. Your car contact is simply oxidized, and the system thinks that it has been left without power and generates an error.
"Mass" between the body and the engine. This happens if your engine is damaged (for example, after an accident), contacts are oxidized, or wire insulation is damaged.
Safety block. The wires in them can also periodically oxidize. As a result, the voltage may also drop. Although the block itself is also worth checking, the reason may be in itself.
Control electrical unit. The error may also appear due to hardware problems. Then I recommend that you contact the service; if you don’t understand it, then it’s better not to get into the firmware yourself.

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How to properly clean contacts

Often the voltage in the on-board network of the VAZ-2114 disappears due to oxidation of the contacts. In this case, you need to clean them, and then try to start the engine again and check the on-board computer readings. Contact cleaning is carried out according to the following rules:

First check the condition of the negative terminal of the battery. If oxide is visible on it, it must be removed using a stiff wire brush or file. Similar work needs to be done with other contacts.
Repeat this work with the positive terminal of the battery.
Another node that must be checked when error 1602 appears is the side of the generator. There is also a wire leading to it, which often oxidizes. It is attached to the generator casing using a nut. If you see oxide on it, that should also be cleaned off.

The remaining conductors can simply be inspected for breaks and winding damage. Heavily worn wires need to be replaced.

Elimination methods

Methods for eliminating error p1602 directly depend on the reason why it was formed in the memory of the electronic control unit. However, before performing the steps listed below, it makes sense to programmatically reset the error. If there are no visible breakdowns, then it is quite possible that the error “Court Controller, loss of supply voltage” was generated accidentally.

We list possible solutions to the problem in the same sequence as the reasons that caused them:

Battery. Use a normally charged battery that holds a charge well and also has the appropriate capacity suitable for a particular vehicle (this is especially true for winter, when difficult engine starts are expected). Periodically check the charge level, electrolyte density, the quality of the terminal contacts on the battery, and if necessary, clean and lubricate them. Clean the contacts on the wires in the same way. If possible, you can check the battery leakage current. Sometimes an action that helps get rid of the error is to remove the negative wire from the battery for about 5 minutes (a few seconds are not enough!!!), and then quickly put it on and set it in such a way as to ensure tight contact between the wire and the terminal battery It is also advisable to first clean and lubricate the contact.
Generator. It makes sense to double-check the operation of the diode bridge, check the voltage at the terminals (on most modern passenger cars the corresponding value should be about 13.7...14.0 V). Check the ground of the generator and, if necessary, inspect the wire and corresponding contacts. Similarly, clean all accessible contacts on the generator, as well as tighten them. You can also re-stripe the wires and make new contacts to improve their quality. Clean the base of the generator mount and the engine block at the point of contact. In some cases, tightening the alternator belt helps (especially if it slips and whistles); if the belt is significantly worn, it is better to replace it with a new one. In rare cases, the generator is completely replaced.
Signaling. Regarding the alarm system, it is advisable to consult with the employees who installed the alarm system on the car, or find documentation for it on the Internet and find out whether it disconnects the battery from the system as protection or not. If yes, then you will have to come to terms with this error, or, as a last resort, change the alarm system to another one without a similar function.
Short-term voltage drop. Usually in this case, this error is simply reset programmatically from the ECU memory. It should not be restored in the future.
"Mass" of the ECU. Check the quality of the ground; if it is damaged, restore the integrity of the contact and/or wire. The chip may be damaged.
Ground connection between the body and the engine. Inspect the wires and contact connections; the tips (if any) may be damaged. If necessary, test the wire with a multimeter to check for continuity or damage to the insulation. If the wire is broken or damaged, it must be replaced with a new one. In this case, it is advisable to use tips.
Fuse box. Check the contacts in the block. Moreover, both coming from the battery and internal ones, directly on the fuses themselves. If necessary, tighten the contacts, remove oxides, and lubricate. It is especially necessary to check the fuse that goes to the electronic control unit, as well as its seat, the quality and cleanliness of the contact, and if necessary, inspect and clean it. It is also advisable to check the condition of the contacts in a special block under the hood. To do this, it is better to use a special contact cleaner.
Electronic control unit. If there is such a possibility, it is advisable to install an ECU of the same model with the same firmware version on the car. At the same time, check whether voltage is coming to the supply terminal of the control unit and what its value is. However, it is best to seek help from official dealers or a car service that repairs electronic “brains,” since reflashing or changing settings yourself can be fraught with big problems.

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As practice shows, error 1602 itself is in most cases harmless, and the car owner finds out about it only when he uses a scanner to remove information from the ECU along with other errors or there is an on-board computer with a screen on which the relevant information is displayed. Therefore, if it does not affect the behavior of the machine (and in most cases this is the case), then the machine can be used and “bothered” about it. As for elimination, the cause is usually poor ground or battery contact.

How to fix the problem?

To fix error P1602, you need to determine the cause of its occurrence. Even during normal operation of the car, simply deleting it from the memory of the electronic control unit, as many VAZ owners do, is wrong. The problem may be more serious than it seems. The only exception is that the code appears after removing the terminal from the battery or in frosty weather.

The first step when an error is detected is to check the battery charge, the condition of its terminals and wires. It is also necessary to test with a multimeter and visually inspect the contacts on the ECU, generator and sensors, ring and evaluate the condition of the wiring by eye. It is often very easy to find the location of broken or oxidized terminals. You can fix these problems yourself.

If the generator or battery is not working properly, it is often possible to restore its functionality. The battery often just needs to be charged with a charger and the terminals cleaned. But many owners also repair the generator themselves. Sometimes it is better to replace these devices.

Other automaker definitions for P1602

Engine Control Module (ECM) Anti-lock Braking System (ABS) / Traction Control System (TCS), CAN Data Bus - Communication Failure (GM).
Battery Voltage Monitor - Malfunction (Toyota).
Engine Control Module (ECM) - Low Battery Voltage (Volkswagen).
Engine control module (ECM) - low battery voltage (Audi).
CAN Data Bus - Anti-lock Braking System (ABS) / Traction Control System (TCS) (Buick).
CAN Data Bus - Anti-lock Braking System (ABS) / Traction Control System (TCS) (Cadillac).
CAN Data Bus - Anti-lock Brake System (ASS) / Traction Control System (TCS) (Chevrolet).
Engine Control Module (ECM) Unprogrammed (Chrysler).
Engine Control Module (ECM) Unprogrammed (Dodge).
Transmission Control Module (TCM) - Serial Communication Problem (Hyundai).
ECM communication with ABS - circuit malfunction (Isuzu).
Engine Control Module (ECM) Unprogrammed (Jeep).
Transmission Control Module (TCM) - Communication Lost (Kia).
Battery voltage monitoring - malfunction (Lexus).
Immobilizer control module/engine control module (ECM) - communication error (Mazda).
ECM for LSI system - communication failure (Mitsubishi).
CAN Data Bus - Anti-lock Brake System (ABS)/Traction Control System (TCS) (Oldsmobile).
Engine Control Module (ECM) Unprogrammed (Plymouth).
CAN data bus. Engine Control Module (ECM) Anti-Lock Braking System (ABS)/Traction Control System (TCS) - Signal Malfunction (Pontiac).
Engine control module (ECM) - faulty (Saab).
CAN Data Bus, Anti-Lock Brake System (ASS), Traction Control System (TCS) to Engine Control Module (ECM) - Lost Communication (Saturn).
Engine Control Module (ECM) - Programming Error (Subaru).
Electronic Throttle System (ETS), Throttle Return Spring - Malfunction (Volvo).

Sources

https://voditeliauto.ru/poleznaya-informaciya/to-i-remont/kod-oshibki-p1602.html
https://elm3.ru/diagnostika/oshibka-p1602
https://remontvazov.com/oshibka-1602-na-vaz-2114
https://kody-oshibok.ru/avtomobili/vaz/oshibka-1602-na-avtomobilyakh-vaz.html
https://etlib.ru/blog/1166-oshibka-r1602

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Loss of voltage in the power supply circuit of the VAZ 2114 controller

Error P1602 on the on-board computers of VAZ 2114, 2110, Kalina vehicles means “On-board network voltage interruption” . Specifically, the on-board computer recorded a temporary, short-term lack of voltage. The problem can lead to battery drain, voltage drop and other problems. One of the most unpleasant problems is that the car will not start at all. Let's figure out the reasons for this error.

Most often, the error is associated with poor contact of the wires to ground, from the generator or on the battery terminals. In simple terms: there is contact, but there is no contact. Therefore, to correct error 1602 on domestic cars Niva, Priora, Grant , etc. contacts need to be cleaned .

The main contact from the generator, which should be thoroughly cleaned. It is located below all other contacts and most often loses contact.

The wire is to ground, look for it from the negative mark. The wire will go to the housing.

Check the contacts on the battery terminals and, if necessary, clean them of oxides.

If you solved the problem in another way, share it with us in the comments.

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marat2008

What are you looking at, a scanner? The scanner may not detect a short-term voltage drop when the starter is turned on. I would like to record it with an oscilloscope on a recorder. Or throw in a battery that is known to be good. It would be a good idea to check the spark plugs for the presence of a resistor and the explosive wires for resistance. Also clean all the masses.

Added after 3 minutes

Johnvaldai

I changed the battery, first of all I passed every single one of the masses. The car started up, ran for half an hour and died with the same error. Apparently the heat increases the resistance somewhere. I'm looking further. Tell me what else I can look at. For now I'm digging through all the harnesses with my hands.

Added after 2 minutes

Added after 3 minutes

I don't know this code.

Scanmateg issues, it is called Immobilizer is not disarmed with its key.

Added after 3 minutes

[quote=Johnvaldai;407785]What are you watching with, a scanner?

I check the voltage with a voltmeter directly from pin 18 of the ECU. Drop to 9.0 V

Error 1602 appears (loss of mains voltage in the controller), while the car is working normally, I cleared the error by removing the terminal from the battery, the error is erased but appears again after a while.

I installed a battery (new) from another car, cleaned the terminals, checked the circuit from the battery positive to pin 18 of the control unit (fuse link, fuse), the result was the same.

Bosch MP7.0 controller.

What could be wrong with the controller?

I advise you to double-check the generator, perhaps the diodes are faulty, check the voltage at the terminals again, it should be 13.7-14.0 V. In general, error 1602 often pops up when the battery is disconnected from the power supply, there is nothing wrong with this error, it will disappear on its own after a while, they fall into the category of “good mistakes”. Perhaps the error occurred due to a large voltage drop during startup (bad battery, cold, thick oil, etc.), due to the voltage drop, the unit automatically increases the opening time of the injectors to compensate for the fuel supply. Check the ground on the ECU, either because of it or because of the TPS.

I advise you to contact an authorized dealer who has the necessary diagnostic equipment and qualifications. As a rule, this is cheaper than long agony.

I also have the same problem because of code 1602. I remove the terminal from the battery and put it back after 15 minutes (I give it a wait), and still, immediately when I turn on the battery, it shows code 1602. I looked at the masses, it seems that they are pressurized everywhere and are not oxidized. I don’t even know what to do. And diagnostics are very far from home. Yes, by the way, what voltage input should be at the input to the controller at terminal 18? And what output from the generator should be no less and no more?? Please help me.