Glow plug with pressure sensor for ŠKODA Kodiaq: how to select and replace without errors

ŠKODA Kodiaq with diesel engines 1.6 TDI and 2.0 TDI equipped with an innovative glow plug system with integrated pressure sensors. These components not only ensure rapid heating of the combustion chamber, but also transmit data to the ECU to optimize fuel injection. However, their failure is one of the most insidious malfunctions, which owners often confuse with problems with the turbine or injectors.

In this article we will analyze how to accurately diagnose a malfunction, select original or high-quality analogues, and also carry out replacement without errors. We will pay special attention to the nuances of working with pressure sensors - their damage during dismantling can result in expensive repairs. The material is based on the experience of service technicians and analysis of typical mistakes of owners Kodiaq 2017–2026.

Symptoms of faulty glow plugs with pressure sensor

Symptoms of failure of these components are often disguised as other diesel engine problems. For example, difficult starting when cold owners blame it on a discharged battery or low-quality fuel, and failures during acceleration - for a clogged particulate filter. However, there are specific signs that directly indicate spark plugs:

• 🔥 Long rotation of the starter (more than 3–4 seconds) before starting, even at above-zero temperatures.
• ⚡ Check Engine with errors P0380 (heat circuit), P0671–P0676 (individual spark plugs) or P025A (low cylinder pressure).
• 📉 Power drop after the engine warms up, the pressure sensor transmits incorrect data, the ECU “strangles” the engine.
• 💨 White smoke from the exhaust at startup - the fuel does not ignite due to the low temperature in the combustion chamber.

Critical point: if at least one spark plug with sensor is faulty, the ECU switches the engine to emergency mode, limiting the speed to 3000–3500 rpm. In this case, the error may not be constantly on, but appear sporadically - for example, in wet weather or after a long stay.

⚠️ Attention: On Kodiaq with motor 2.0 TDI (240 hp) A faulty glow plug can lead to fuel detonation and damage to the piston group. At the first sign of unstable engine operation, check the spark plugs with a diagnostic scanner!

Articles and analogues: what to install on the ŠKODA Kodiaq

Original glow plugs with pressure sensor for Kodiaq supplies Bosch, but under the brand ŠKODA. Their article numbers depend on the year of manufacture and engine power:

Engine model	Original article	Analogue (Bosch)	Note
1.6 TDI (115 hp)	04L 905 051 F	0 250 201 016	From 2017 to 2020
2.0 TDI (150 hp)	04L 905 051 J	0 250 201 022	Without particulate filter
2.0 TDI (190–240 hp)	04L 905 051 K	0 250 201 025	With pressure sensor Piezo

Important: spark plugs for 2.0 TDI (240 hp) have Unique pressure sensor design with ceramic tip, which cannot be damaged during installation. Analogues from Beru or NGK not suitable - they are not compatible with the ECU data exchange protocol Bosch EDC17.

When choosing analogues, pay attention to:

• 🔧 Length of threaded part - must match the original to the millimeter.
• 📏 Torque - for Kodiaq it amounts to 20 Nm (tightening leads to damage to the sensor).
• 🔌 Connector type - used on engines after 2021 mini-Deutsch instead of standard Bosch.

Diagnostics: how to check glow plugs with a pressure sensor

Checking these spark plugs differs from traditional ones - due to the integrated pressure sensor, you cannot use the multimeter in the “diagnosis” mode. Here is a step-by-step diagnostic algorithm:

1. Reading errors scanner (for example, VCDS or Launch X431). Codes P0671–P0676 indicate an open circuit of a particular spark plug, and P025A - a faulty pressure sensor.
2. Resistance check:
   • 🔋 Disconnect the spark plug connector.
   • 📊 Measure the resistance between the filament contacts (should be 0.5–1.5 Ohm).
   • 📊 Measure the resistance of the pressure sensor (between the signal and ground contacts - 1–5 kOhm).
3. Visual inspection:
   • 🔍 Carbon deposits on the tip of the spark plug are a sign of an over-rich mixture or a faulty injector.
   • 💧 Oil smudges are evidence of wear on the o-ring or turbine.

If the resistance of the pressure sensor tends to infinity or is equal to zero, the spark plug must be replaced. Important: on Kodiaq with motor 2.0 TDI (240 hp) The pressure sensor cannot be repaired - it is soldered into the spark plug body.

What to do if the scanner does not show an error, but the symptoms remain?

If the diagnostics do not reveal errors, but the engine is unstable, check:

1. **Wiring integrity** from the spark plugs to the ECU (wires near the exhaust manifold often fray).

2. **Quality of “ground”** on the engine - oxidized contacts can distort sensor signals.

3. **Fuel pressure** in the rail - low pressure (less than 250 bar) simulates a faulty spark plugs.

Step-by-step instructions for replacing glow plugs

Replacing spark plugs with Kodiaq requires caution - errors during dismantling can damage the threads in the cylinder head or the pressure sensor. Here are the detailed instructions:

Remove the negative terminal of the battery|Clean the area around the spark plugs with compressed air|Prepare a torque wrench (20 Nm)|Check for new O-rings-->

1. Removing old spark plugs:
   • 🔧 Disconnect the power connectors from the spark plugs (press the lock and pull up).
   • 🔨 Carefully clean the wells of dirt so that it does not get into the cylinders.
   • 🔩 Unscrew the spark plugs only on a warm engine (temperature not lower than 60°C) - this will prevent thread breakage.
2. Installing new spark plugs:
   • 🛠️ Apply to the spark plug thread non-stick paste (for example, Loctite 577).
   • 🔧 Tighten the spark plugs 2 stages: first by hand, then with a torque wrench until 20 Nm.
   • 🔌 Connect the connectors, making sure that the latches click into place.

After replacement be sure to reset the adaptations through a diagnostic scanner (in the unit EDC17 select "Reset glow plug adaptations"). This will allow the ECU to correctly interpret data from the new pressure sensors.

⚠️ Attention: On Kodiaq with motor 1.6 TDI The glow plugs are located under the intake manifold. To access them, you will need to remove the manifold, which increases the work time to 3–4 hours. If you have no experience, it is better to contact the service.

Typical replacement mistakes and how to avoid them

Even experienced craftsmen make mistakes when working with glow plugs Kodiaq. Here are the most common ones and how to prevent them:

• 🔧 Re-upholstery of spark plugs — leads to a cut of the pressure sensor or a crack in the housing. Always use a torque wrench!
• 🧹 Dirt getting into the cylinders — before dismantling, clean the wells with compressed air or a vacuum cleaner.
• 🔌 Confusion with connectors - on engines 2.0 TDI after 2020 connectors are used mini-Deutsch, which are not compatible with old spark plugs.
• 📊 Ignoring reset adaptations - without this, the ECU will use old calibration data, which will lead to unstable engine operation.

Another critical error - using sealant instead of o-rings. Sealant may enter the combustion chamber and cause detonation. Original spark plugs Bosch always come with new rings - they must be installed.

Service life and prevention: how to extend the life of spark plugs

The manufacturer declares the lifespan of glow plugs for Kodiaq in 100,000–120,000 km, but in practice they fail after 60,000–80,000 km. The main reasons for premature wear:

• ⛽ Low fuel quality - sulfur in diesel forms carbon deposits on the tip of the spark plug.
• 🔥 Frequent short trips — the spark plugs do not have time to warm up to operating temperature.
• 💧 Oil entering the combustion chamber - due to wear of the turbine or rings.
• ⚡ Unstable voltage in the on-board network (less than 11.5 V at startup).

To extend service life:

• 🛢️ Fuel with fuel with a cetane number of at least 51 (for example, Shell V-Power Diesel).
• 🔋 Check the battery voltage regularly - it should be at least 12.6 V with the engine turned off.
• 🔧 Every 30,000 km clean the spark plugs from carbon deposits using a special additive (for example, Liqui Moly Diesel Purge).

On Kodiaq 2023–2026 with motor 2.0 TDI glow plugs have an improved anti-corrosion coating, but only if oils are used VW 507.00 or 508.00. The use of other oils reduces their service life by 30–40%.

FAQ: answers to frequently asked questions

Is it possible to drive with one faulty glow plug?

Technically possible, but not advisable. On Kodiaq with motor 2.0 TDI A faulty spark plug leads to an imbalance of temperature in the cylinders, which accelerates wear of the turbine and particulate filter. In addition, the Forced ECU limits power to 70–80% of rated power.

How to distinguish an original spark plug from a fake?

Original spark plugs Bosch for Kodiaq have:

• Laser engraving of the article number on the case (not a sticker!).
• Ceramic pressure sensor tip with holographic mark.
• Packaging with a QR code that can be checked on the website Bosch.

Counterfeits often have duller metal and plastic connector retainers instead of metal ones.

Do I need to change all the spark plugs at the same time?

Yes, even if only one is faulty. Glow plugs wear out evenly, and if one fails, the others will soon follow suit. Partial replacement will lead to imbalance of the cylinders and accelerated engine wear.

Is it possible to clean glow plugs?

Mechanical cleaning (with sandpaper or brush) is prohibited - it damages the protective coating. Only chemical cleaning in an ultrasonic bath or special additives (for example, Wynn's Diesel Injector Cleaner). However, this is a temporary measure - if the spark plugs are severely worn, they must be replaced.

How much does it cost to replace glow plugs at a service center?

The cost of work depends on the motor:

• 1.6 TDI: 8,000–12,000 rub. (requires removal of intake manifold).
• 2.0 TDI (150–190 hp): 5,000–8,000 rub.
• 2.0 TDI (240 hp): 10,000–15,000 rub. (due to the difficulty of accessing spark plugs).

The price of original spark plugs is from 2,500 to 4,000 rubles. per piece.