Error E-03 on the gas analyzer display GAK GS-8 2nd generation indicates a malfunction of the oxygen sensor (lambda probe) or an open circuit in its heating. This problem blocks the correct measurement of CO/CH in the exhaust gases, which automatically makes it impossible to pass a technical inspection. In 80% of cases, the culprit is oxidation of the sensor connector contacts or failure of its heating element - the test begins with these components.

Second generation GS-8 (2018–2023 release) differs from the first in a modified control board and updated software, but remains vulnerable to voltage surges in the on-board network. If the device does not turn on at all or gives erratic readings, first rule out power problems: the voltage at the terminals should be stable in the range 12.8–14.4V. Using cheap power supplies with ripples greater than 50 mV often leads to microcontroller failure.

Typical malfunctions of GAK GS-8 2nd generation and their symptoms

Gas analyzers of this generation have characteristic “diseases” that are manifested by specific error codes or device behavior. Below is a table of the most common problems indicating the primary symptoms.

Error code Symptoms Probable Cause Urgency of repair
E-01 Does not turn on, indicators do not light up Open circuit, fuse F1 (3A) has blown High
E-03 CO/CH readings too high or zero The lambda probe or its heating is faulty Average
E-05 Spontaneous shutdown during operation Board overheating or firmware failure High
E-08 Communication error with PC via USB/Bluetooth Damaged connector or drivers Low

The error deserves special attention E-05: it often occurs when using the device in hot workshops (temperatures above 35°C) or when the internal ventilation ducts are dusty. If the gas analyzer turns off after 10–15 minutes of operation, check the condition of the radiator on the control board - its fins should not be clogged with dust.

⚠️ Attention: Never connect GAK GS-8 2nd generation to the vehicle's on-board network through the cigarette lighter without a voltage stabilizer. Jumps above 15V are guaranteed to damage the power converter on the board.

Lambda probe diagnostics: step-by-step instructions

The oxygen sensor is the most vulnerable element of the gas analyzer. Its verification begins with a visual inspection:

  • 🔍 Hull integrity: Cracks or melting on the ceramic tip indicate thermal damage.
  • 🔌 Connector status: oxidized or burnt contacts (especially pins 3 and 4 - heated) require cleaning.
  • 📉 Heater resistance: Use a multimeter to measure the resistance between pins 3 and 4 - normal 2–10 ohms. Infinity = break.

For in-depth diagnostics, you will need an oscilloscope or a specialized lambda probe tester. Connect the sensor to the gas analyzer and start the test mode through the menu Service → Diagnostics → O2 Test. If the voltage at the sensor output does not change when a reference gas mixture is supplied (for example, propane-butane), the sensor must be replaced.

1. Inspect the housing for cracks and melting

2. Check the heater resistance (2–10 Ohm)

3. Clean the connector contacts with alcohol

4. Carry out a test in the "O2 Diagnostics" mode-->

The cost of the original sensor for GS-8 2nd generation — from 4,500 rubles (article GS8-O2-2G). Analogues are cheaper (about 3,000 rubles), but often have a shorter resource. When replacing, be sure to use thermal paste to seal the threaded connection.

PC communication errors: causes and solutions

Problems with data transfer via USB or Bluetooth are the second most common problem. If the gas analyzer is not detected by the program GAK-Soft, follow these steps:

  1. Reinstall the drivers from the manufacturer's official website (section "Support → GS-8 2G").
  2. Check the integrity of the USB cable - the braiding at the connector or internal wires are often damaged.
  3. In the device menu (Settings → Communication) reset the connection settings to factory settings.
  4. For Bluetooth: Remove all paired devices in Windows and pair again.

If after these steps the connection is not restored, the problem may lie in the USB-UART converter chip (usually CH340 or FT232). It is checked with a multimeter for a short circuit between the terminals TX/RX and the earth. Replacing a microcircuit requires soldering work using a hair dryer.

USB|Bluetooth|Both options are the same|No problems there-->

Gas analyzer calibration: when and how to do it

Calibration GAK GS-8 2nd generation required in three cases:

  1. After replacing the lambda probe or temperature sensor.
  2. If the CO/CH readings differ from the reference values by more than 15%.
  3. Once every 6 months with intensive use (standard GOST R 52033-2003).

For calibration you will need reference gas mixture (e.g. CO cylinder 4.5% ±0.05%). Connect the cylinder to the inlet fitting of the device through the reducer, then select from the menu Service → Calibration → Auto. The device will independently perform 3 measurement cycles. If calibration fails (error E-12), check:

  • 🔧 Tightness of connections - even micro-suction of air distorts the results.
  • 📊 Gas pressure in the cylinder (must be at least 2 bar).
  • 🕒 Sensor warm-up time (minimum 10 minutes after switching on).
⚠️ Attention: Never use homemade gas mixtures or household gas from cans for calibration. This will cause permanent damage to the CO sensor and will void the warranty.
What should I do if the calibration is not saved?

If, after successful calibration, the device resets its settings when turned off, the problem is a dead memory battery (CR2032 on the board). Replace it with a new one, having previously saved the current settings through the menu Service → Backup.-->

Control board repair

common defects

Fee GS-8 2nd generation has several "weak points":

  • 🔥 Burnt resistors in the lambda probe power supply circuit (nominal 10 Ohm/5 W).
  • 📟 Swollen capacitors near the microcontroller (especially 1000uF/16V).
  • 🔌 Oxidized tracks under the USB connector (clean with alcohol + brush).

To repair the board you will need:

  1. Soldering station with temperature control (maximum 350°C for SMD components).
  2. Flux RMA-223 and solder Sn63Pb37.
  3. Magnifying glass with ×10 magnification for examining microcracks.

Typical error repair scenario E-01 (no power):

  1. Ring the fuse F1 (3A) for a break.
  2. Check the diode D3 (1N4007) for breakdown.
  3. Replace the transistor Q1 (IRFZ44N) if it gets hot or has black spots.

Firmware and software update

Firmware GS-8 2nd generation updated through the program GAK-Soft (version 3.5 or later). Algorithm of actions:

  1. Download the archive with the firmware from the official website (section "Files → GS-8 2G").
  2. Connect the gas analyzer to the PC and run the utility GS8_FlashTool.exe.
  3. Select the firmware file (.bin) and click "Update".

Interruption of the update process (for example, due to a power failure) leads to the device becoming bricked. In this case, flashing via the JTAG port using a programmer is required. The cost of such a service in service centers is from 3,000 rubles.

Software version Changes Release date
3.1.4 Fixed error in CH calculation at high CO concentrations March 2022
3.2.0 Added Bluetooth 5.0 support June 2022
3.3.1 Improved stability of communication with PC via USB November 2023

Prevention and care of the device

Service life GAK GS-8 2nd generation directly depends on operating conditions. Basic rules:

  • 🚗 Transportation: Always use the original case with shock-absorbing inserts.
  • 🌡️ Temperature: operation at −10°C...+40°C, storage −20°C...+50°C.
  • 🔋 Food: Disconnect the device from the network if it is not used for a long time (more than 3 days).
  • 🧹 Cleaning: Once a month, blow out the inlet fitting with compressed air (pressure no more than 2 bar).

To clean the optical surfaces of the sensors, use isopropyl alcohol (99%) and lint-free wipes. It is forbidden to use acetone or hydrocarbon-based solvents - they destroy the protective coating of the sensors.

💡

Regular cleaning of the ventilation holes on the back of the device (every 3 months) prevents overheating of the board and error E-05.

FAQ: Frequently asked questions about GAK GS-8 2nd generation

Is it possible to use a sensor from the 1st generation GS-8 in the 2G model?

No, the sensors are not compatible. In the second generation, the heating circuit for the lambda probe was changed (an additional thermistor was added to control the temperature), and the connector has a different key. Installing a sensor from 1G will lead to an error E-03 and possible damage to the board.

How to reset all settings to factory settings?

To do a full reset:

  1. Turn off the device.
  2. Press and hold the button Menu and hold it when turning it on.
  3. After 5 seconds the display will show RESET OK.
Attention: After reset, recalibration will be required!
Why does the device show CO=0% when the engine is running?

Reasons:

  • The CO sensor is faulty (check the resistance between pins 1 and 2 - it should be 40-60 ohms).
  • The inlet fitting or gas sampling tube is clogged.
  • Firmware error (update software to version 3.3.1 or later).
Where can I download the official software for GS-8 2G?

Official files are available on the manufacturer’s website in the section Support → Software. To download, you will need to indicate the serial number of the device (located on the back panel). Alternative sources (torrents, forums) may contain viruses or outdated versions.

How often do you need to change the lambda probe?

The sensor life is about 2,000 hours of operation or 3 years under moderate load. Signs of wear:

  • Extended warm-up time (more than 2 minutes).
  • Incorrect readings during repeated measurements.
  • Error E-03 appears even after cleaning the contacts.