Internal combustion engine Skoda Octavia Tour with a displacement of 1.4 liters, it has a complex control system where each component plays a critical role. One of these nodes is crankshaft position sensor, which is often called DPKV. Without correct data from this element, the electronic control unit cannot synchronize the operation of the fuel injectors and the ignition system, which makes it impossible to start the engine.
Car owners Octavia with motors of the AUB or BFQ series, they often encounter problems in this part. It operates in conditions of high temperatures and vibrations, which over time leads to degradation of the magnet or breakage of the internal winding. Understanding of operating principles and symptoms of failure crankshaft sensor will help you quickly diagnose the problem and avoid costly engine repairs or purchasing a new ECU.
Ignoring signs of malfunction can lead to the car stalling at the most inopportune moment, for example, when driving in heavy city traffic. Timely replacement of this inexpensive component guarantees stable engine operation and no starting problems in the cold season. We will analyze in detail how to recognize a breakdown and carry out repairs yourself.
Functional purpose and principle of operation of the sensor
Main task crankshaft position sensor β transmission to the control unit of information about the rotation speed and exact position of the crankshaft. On the engine 1.4 MPI the sensor reads the teeth of a special disk that is mounted on the flywheel or crankshaft pulley. This disc has missing teeth, creating a specific signal that the ECU interprets as the top dead center of the cylinder.
If the signal is from DPKV missing or distorted, the engine management system goes into emergency mode or completely blocks the fuel supply and spark. This happens because the computer simply does not know at what point to send a spark to the cylinder. Synchronization operation of the gas distribution mechanism and injection system becomes impossible without this data.
Sensor design Skoda Octavia Tour is an inductive element sensitive to a magnetic field. The distance between the sensor tip and the ring gear must be strictly maintained. Even the slightest deviation or metal shavings getting between them can disrupt the operation of the entire system.
β οΈ Attention: If the crankshaft sensor fails, the engine will not start, even if the starter turns properly and the battery is fully charged.
It is important to understand that this component does not have moving parts inside the case, but its operation directly depends on the mechanical condition of the drive disk and the condition of the connection wires. Any disruption to the circuit integrity will result in signal loss.
Electronic control unit ECU constantly monitors the signal from the sensor. If discrepancies are detected between the expected and actual speed values, the system stores an error code in memory. This allows diagnostic technicians to quickly localize the problem.
The main symptoms of a malfunction on the 1.4 MPI engine
Breakdown crankshaft sensor on Skoda Octavia manifests itself quite clearly and often leaves no doubt about the diagnosis. The most common symptom is a sudden stop of a running engine without the ability to restart. The car can be driving at high speed and suddenly stall, as if someone had turned off the ignition.
Another characteristic symptom is unstable engine operation at idle. The engine starts to stall, the speed fluctuates, and when you try to move away, jerks occur. This is due to the fact that the ECU receives incorrect data about the position of the shaft and supplies fuel or spark at the wrong times.
Owners often notice the following problems in the behavior of the car:
- π₯ The car starts with great difficulty, the starter turns for a long time, but the engine does not catch.
- βοΈ The Check Engine light comes on on the dashboard and sometimes flashes when driving.
- π Loss of power when you press the gas pedal sharply, especially on an uphill slope.
Sometimes the malfunction only appears when the engine warms up. A cold motor starts normally, but after reaching operating temperature the sensor stops producing a signal due to changes in winding parameters due to heating. This is a so-called βfloatingβ defect, which is difficult to diagnose without special equipment.
It is worth noting that the symptoms may be similar to problems in the ignition module or coils, but it is the lack of a synchronization signal that is fatal to engine operation. Synchronization - a key point that ensures the stability of all systems.
- The car stalled while driving
- Takes a long time to start when hot
- Trouble and floating speed
- Check showed error P0335
OBDII Diagnostics and Error Codes
To accurately diagnose the problem, you need to connect the OBDII scanner to the car connector. On Skoda Octavia Tour The most likely error code for problems with the crankshaft sensor is P0335. This code means "Crankshaft Position Sensor A Circuit Malfunction."
Additional codes may also occur, such as P0336 (incorrect range/sensor operation) or P0337 (low signal level). These errors indicate that the signal is either completely absent or its amplitude is too small for correct processing by the control unit.
The diagnostic procedure includes:
- π Reading error codes using a diagnostic scanner.
- π Check the integrity of the wires and sensor connection connector.
- 𧲠Measuring the resistance of the sensor winding with a multimeter.
The resistance of a working sensor on a 1.4 engine is usually in the range from 500 to 1500 Ohms, but the exact values depend on the manufacturer of the part. If the multimeter shows an open circuit (infinite resistance) or a short circuit to the case, the sensor must be replaced.
Sometimes the problem lies not in the sensor itself, but in the wiring. Vibrations can lead to chafing of the insulation or oxidation of the contacts in the connector. Visual inspection of the wiring harness going to DPKV, is a mandatory diagnostic step.
What does code P0335 mean?
Code P0335 indicates that the electronic control module is not receiving a signal from the crankshaft position sensor or the signal has not been received for a certain period of time. This may be caused by an open circuit, a short circuit, a malfunction of the sensor itself, or a damaged toothed disk.
Step-by-step instructions for replacing the sensor
Replacement crankshaft sensor on Skoda Octavia Tour 1.4 - a task of medium complexity that can be completed independently if you have a basic set of tools. The sensor is usually located at the bottom of the engine, near the clutch housing or flywheel, and is accessible from underneath the vehicle.
Before starting work, you need to prepare the place: turn off the engine, turn on the handbrake and lift the car on a lift or place it on a pit. Be sure to disconnect the negative terminal of the battery to avoid short circuit when disconnecting the connector.
To complete the work you will need the following tool:
- π§ A set of socket heads (usually 8 or 10 mm).
- π© Screwdriver for removing connector clamps.
- π§Ό A rag and carburetor cleaner to clean the installation area.
βοΈ Preparing to replace the sensor
First find the sensor. It is secured with one bolt and has an electrical connector. Gently press the connector latch and disconnect it. If the connector is dirty, clean it before installing a new sensor. Then unscrew the fastening bolt and remove the old element.
Clean the seat from dirt and oil. It is important that there are no metal filings left on the surface, as they may interfere with the operation of the new sensor. Install new DPKV, carefully tighten the mounting bolt, but do not use excessive force to avoid stripping the thread. Connect the electrical connector until you hear a characteristic click.
After assembly, it is necessary to reset errors in the ECU memory and check engine operation. Start the engine and make sure it runs smoothly without misfiring. Check the scanner for errors.
Before installing a new sensor, apply a small amount of graphite grease to the seat; this will make future removal easier and improve heat dissipation.
Selection of original spare parts and analogues
When choosing a sensor for Skoda Octavia It is important to consider the quality of the product. Original sensor from the concern VAG has a number 036 906 433 (or similar depending on the year of manufacture), but is often sold under the brand Hella or Bosch. These manufacturers are suppliers to the assembly line, so their products guarantee precise performance.
There are many analogues on the market that can be cheaper than the original. However, in the case of synchronization sensors, savings can lead to frequent breakdowns. Cheap Chinese copies often have unstable winding parameters and quickly fail when heated.
Comparative table of popular crankshaft sensor manufacturers for 1.4 MPI:
| Manufacturer | Type | Approximate price | Features |
|---|---|---|---|
| Hella | Original/OEM | High | Stable work, long service life |
| Bosch | OEM | High | High signal accuracy |
| Febi Bilstein | Analogue | Average | Good price/quality ratio |
| Stellox | Budget | Low | Risk of rapid failure |
It is recommended to choose the details with the marking VAG or trusted suppliers. When buying, be sure to check the integrity of the package and the presence of a protective film on the connector. Quality The material of the housing and the tightness of the connector play a key role in the durability of the part.
Original VAG sensors, manufactured by Hella or Bosch, provide the most reliable synchronization and rarely fail again during the warranty period.
Installation nuances and possible problems
When installing a new sensor, it is critical to observe the gap between the tip and the cog crown. On some models, this gap is adjusted automatically due to the shape of the sensor, but on older copies, a gasket may be required. If the gasket is installed incorrectly or is missing, the sensor can touch the disk and jam.
A common mistake of beginners is the wrong connection of the connector. The contacts inside the chips should fit tightly. If the connector is luftitis, this will lead to loss of contact on the buds. Use insulation tape or heat shrinkage to fix the connector if it is not held tight.
It is important to check the condition of the toothed crown of a flywheel or pulley. If the teeth have chips, dirt or oil, the sensor will not be able to read the signal correctly. Clean the disc with rags dipped in the cleaner before installing the new sensor.
β οΈ Warning: Never attempt to adjust the gap manually by bending the sensor body. This will cause mechanical damage and incorrect readings.
If after replacing the sensor, the error does not disappear or the engine continues to work unstable, check the integrity of the wire harness to the ECU itself. Perhaps the gap is in a hard-to-reach place of the tourniquet, and the sensor has nothing to do with it.
It is also worth paying attention to the state of the oil-reflective ring. On some engines, it may shift, which changes the position of the disc relative to the sensor. In this case, a deeper repair will be required.
How to check the gap without special equipment?
Without a special probe, it is difficult to check the gap, but you can visually make sure that the sensor does not touch the disk. When installed, it should stand tightly, but without effort. If it hangs, then there is a problem with the mounting or gasket.
FAQ: Frequently asked questions
Is it possible to start the engine without a crankshaft sensor?
No, it's impossible to start the engine without a signal from the crankshaft sensor. The ECU wonβt know when to fire a spark and inject fuel, so the system blocks the launch.
How long does it take to replace a sensor?
If you have access from the bottom of the car, the replacement takes 30 to 60 minutes. If you need to remove protection or other elements, the time can be increased to 1.5 hours.
Why does the sensor fail so often?
High engine temperature, vibrations and oil or dirt hitting the sensitive element lead to degradation of materials. The quality of the detail itself also affects.
Do I need to reset errors after replacement?
Yes, after replacement, you need to connect the scanner and reset the error codes. Sometimes the error disappears after several cycles of starting and stopping the engine, but manual resetting is more reliable.
Does the crankshaft sensor affect fuel consumption?
Yes, with a faulty sensor or incorrect readings, the system can supply the wrong dose of fuel, which leads to increased consumption and unstable operation of the engine.