The appearance of an error associated with code 1108 or P0108 on the car Nissan, often becomes a serious cause for concern for owners, as this indicates a critical malfunction in the engine management system. In most cases, we are talking about a failure of the circuit or signal of the absolute pressure sensor in the intake manifold (MAP sensor), which is the “eye” of the electronic control unit that monitors the load on the engine. Ignoring such a signal can lead to increased fuel consumption, unstable engine idling, and even failure to start under extreme conditions.
Many car owners mistakenly believe that simply resetting the error through a diagnostic scanner is enough for the problem to disappear forever. However, if the physical cause of the failure has not been eliminated - be it a broken wiring, sticking contacts, or failure of the sensor — the error will return almost immediately after several cycles of engine operation. Diagnostics in this case, it should be comprehensive and include not only reading codes, but also checking electrical circuits, as well as analyzing readings in real time.
For owners Nissan Almera, Teana and other models with engines of the HR or MR series, this problem occurs quite often due to the design features of the intake system and the sensitivity of the electronics to voltage changes. Understanding the operating principle of the system and the ability to correctly interpret data from diagnostic equipment can save significant money on visits to the service center. In this article we will analyze in detail all aspects of the error, methods for eliminating it yourself, and nuances that are often missed during repairs.
The essence of the problem and classification of fault codes
When the "Check Engine" light comes on on the dashboard and the scanner displays a code containing the numbers 1108 or P0108, the engine control unit (ECU) detects an abnormally high voltage in the absolute pressure sensor circuit. This means that the signal coming from the sensor exceeds the permissible threshold, which is usually around 4.5–4.9 volts. Under normal conditions, the voltage should vary depending on the load: at idle it is low, and when you press the gas it increases.
It is important to distinguish the context in which the code appears. On some systems Nissan A P1108 code may indicate a problem with the mass air flow (MAF) sensor or its circuit if integrated with a MAP sensor, or a specific problem with the throttle control circuit. However, most often this code hides precisely a problem with the MAP sensor, which transmits inflated data on the pressure in the intake tract. The ECU interprets this as an extreme load on the engine, which forces it to enrich the mixture to critical values.
Symptoms of such a malfunction appear immediately and are clearly expressed: the car loses traction, the speed fluctuates, and the engine may stall when trying to move away. In some cases, the system may go into emergency mode, limiting speed and revolutions to prevent damage to the catalyst or the engine itself due to an over-rich fuel mixture. Diagnostics at this stage it becomes a mandatory procedure.
The main reasons for the error to appear on Nissan cars
There may be several reasons why a pressure sensor may malfunction, and they range from trivial contamination to serious problems with the electronics. The most common cause is physical damage to the sensor due to exposure to high temperatures, vibrations or oil entering the intake manifold. Oil often gets there from the crankcase ventilation system, clogging the sensor channels and distorting its readings.
The second most common reason lies in the electrical wiring. The insulation of the wires may rub against the motor housing or other components, leading to a short circuit to positive or signal interruption. It is also worth paying attention to the sensor connection connector: the contacts there may oxidize or become loose, especially if the car was operated in conditions of high humidity or dirt. Check Wiring harness integrity is one of the first steps in troubleshooting.
Often the problem lies not in the sensor, but in the intake manifold itself. If there is leakage of unaccounted air in the system through gaskets or cracks, the pressure in the intake tract will be unstable, which can throw off the sensor readings. In addition, malfunctions of the vacuum tubes that connect the sensor to the manifold can also cause a false alarm. Vacuum Over time, the lines become brittle and crack.
- 🔧 Contamination of the sensor’s sensitive element with oil soot or dust.
- ⚡ Open or short circuit in the wiring of the sensor signal circuit.
- 🌡️ Malfunction of the electronic component itself (internal chip failure).
- 🔌 Oxidation or poor contact in the connector connecting to the ECU.
Sometimes the reason may be hidden in the software part of the ECU, especially on cars with high mileage, where the factory calibration may not correspond to actual operating conditions due to engine wear. In such cases, simply replacing the sensor will not work, and flashing or adaptation will be required.
Step-by-step diagnostics and testing with a multimeter
To accurately determine the cause of the error, it is necessary to conduct a thorough electrical diagnosis using a multimeter. You should start with a visual inspection of the sensor and its connector. Make sure that there are no cracks on the case and that the wires do not show signs of overheating or mechanical damage. If the connector is oxidized, it must be cleaned with coupling fluid and dried before further action.
Next, you need to check the presence of supply voltage at the sensor. To do this, disconnect the connector, turn on the ignition (but do not start the engine) and measure the voltage between the power contact and ground. Typically this value is around 5 volts. If there is no voltage, the problem lies in the power circuit or in the control unit itself. Lack of power makes further testing of the sensor itself pointless.
After checking the power, you need to measure the ground circuit resistance and signal. Connect the multimeter probes to the appropriate contacts and compare the obtained values with the standard data for your model Nissan. It is also important to check if the signal shorts to ground or positive when moving the wiring harness, which may indicate a hidden break within the insulation. Measurement should be carried out at different throttle positions.
Pay special attention to vacuum tubes. Disconnect them from the sensor and check for cracks or peeling. Blow them out for blockages. If the tube is clogged or damaged, the sensor will not be able to read air pressure correctly, resulting in an error. In some cases, replacing the tube with a new one helps, even in the absence of visible damage, since the material may lose its elasticity.
- 🔌 Check the supply voltage (should be ~5V) at the sensor connector.
- 📉 Checking the sensor signal in dynamics (voltage change when pressing the gas).
- 🧪 Checking the integrity of vacuum tubes and the absence of air leaks.
- 💻 Reading sensor readings through a diagnostic scanner in real time.
⚠️ Attention: When taking measurements with a multimeter on a running engine, be careful not to short the probes to moving parts or hot elements of the engine.
- Do it yourself with a multimeter
- OBD2 scanner
- I contact the service
- I don't know how to check
Procedure for replacing and installing a new sensor
If diagnostics confirm a malfunction of the sensor itself, it must be replaced. Replacement process on most models Nissan is not particularly difficult and can be done in a garage. Before starting work, make sure the engine is cool to avoid burns. Open the hood and locate the pressure sensor, which is usually located on the intake manifold, closest to the throttle body.
First, disconnect the electrical connector by pressing the latch. Be careful not to break the plastic clip. Then unscrew the mounting screw or nut holding the sensor in place. On some models, the sensor may be inserted into a rubber sleeve or have a threaded connection. Carefully remove the old element, being careful not to damage the gasket or O-ring.
Before installing a new sensor, be sure to check the condition of the seat and clean it of dirt and oil residues. Install a new O-ring if included. Insert the new sensor into place and tighten the fasteners with moderate force to avoid stripping the threads or crushing the plastic housing. Connect the electrical connector until you hear a characteristic click.
☑️ Replacing the pressure sensor
After installation, it is necessary to carry out an adaptation procedure. To do this, it is often enough to simply reset the error through a scanner or disconnect the battery for 10–15 minutes to erase errors from the ECU memory. Then start the engine and let it idle for a few minutes. If the error does not return and the pressure readings are normal, the work was completed successfully.
- 🛠️ Use an original sensor or a high-quality analogue with a certificate.
- 🧹 Clean the seat from soot and oil before installation.
- 🔒 Check the tightness of the connection after installation.
⚠️ Caution: Never use sealants or lubricants on the sensor threads unless specified by the manufacturer, as this may result in incorrect pressure readings.
Software methods for solving and resetting errors
Sometimes the problem is not solved by replacing the sensor if the error was caused by a software glitch or incorrect ECU calibration. In such cases, it is necessary to turn to diagnostic equipment that can not only read codes, but also change system operating parameters. Reset errors via Clear Codes is a mandatory step after physical repair.
On modern cars Nissan A throttle learning or idle adaptation procedure may be required. If these procedures are not followed, the engine may run unstably even after replacing the sensor. For this purpose, specialized software is used, such as CONSULT-III or its analogues. The learning process includes warming up the engine, disconnecting and connecting the load, and keeping the engine idling for a certain time.
In rare cases, it may be necessary to reflash the engine control unit. This is relevant if the error occurs due to an error in the factory firmware, which incorrectly interprets sensor signals under certain operating conditions. Software updates often resolve these issues and improve overall engine responsiveness.
What should I do if the error returns after a reset?
If the P1108 error returns immediately after a reset, it indicates that the problem has not been physically corrected. Check all vacuum lines for cracks, make sure there are no air leaks, and check the wiring for short circuits. It is also possible that the new sensor is defective or incompatible with your model.
If the sensor is really faulty or the wiring is damaged, no amount of flashing will help for long. However, correct settings can significantly improve system performance after replacing components.
Table of typical values and diagnostic parameters
For ease of diagnosis, below is a table with typical voltage and pressure values that can be expected when operating a working system on various models Nissan. This data will help you quickly assess whether the sensor is in working order.
| Working Condition | Voltage (V) | Pressure (kPa) | Expected signal |
|---|---|---|---|
| Ignition on (engine off) | 0.8 – 1.2 | 100 – 105 | Atmospheric pressure |
| Idling (warm engine) | 0.4 – 0.6 | 30 – 45 | Low pressure (vacuum) |
| Sharp pressure on the gas | 2.5 – 4.5 | 80 – 100 | Increase in pressure |
| Error P1108 (signal too high) | > 4.8 | > 110 | Abnormally high voltage |
Before starting diagnostics, be sure to warm up the engine to operating temperature, as a cold engine may give distorted pressure readings, which will lead to false conclusions.
Prevention and operating tips
To avoid the recurrence of error P1108 in the future, you must follow simple rules for operating and regularly servicing your vehicle. Regular oil changes and the use of high-quality filters will help reduce the amount of oil vapor entering the intake manifold through the crankcase ventilation system. This will extend the life of the sensor and other intake system components.
It is also recommended to periodically check the condition of vacuum tubes and hoses, especially if the car is operated in high temperatures or on dusty roads. Replacing old, dull pipes with new ones is a cheap and effective preventative measure. Do not ignore signs of unstable engine operation, such as floating speed or failures during acceleration.
Use only high-quality gasoline that meets the manufacturer's requirements. Bad fuel can cause carbon deposits to form on the valves and intake tract, which will ultimately affect the performance of the pressure sensor. Regular diagnostics of the engine management system at a service station will identify potential problems at an early stage.
⚠️ Attention: If you notice that fuel consumption has increased sharply and the engine is running unevenly, do not delay diagnostics. This may be the first sign of a malfunction of the pressure sensor, which has already begun to produce incorrect data.
Regularly checking the condition of the vacuum tubes and the cleanliness of the crankcase ventilation system is the key to long-term operation of the absolute pressure sensor and the absence of P1108 errors.
Frequently asked questions and answers (FAQ)
Is it possible to drive with error code P1108?
Technically it is possible to drive, but it is not recommended. The engine will operate in emergency mode, fuel consumption will increase significantly, and power will decrease. In addition, prolonged driving with an over-rich mixture can lead to failure of the catalyst and spark plugs.
How much does it cost to replace a pressure sensor on a Nissan?
The cost depends on the car model and the selected sensor. An original sensor can cost from 3,000 to 8,000 rubles, while high-quality analogues will cost less. Replacement work usually takes 30–60 minutes and costs from 1000 to 2500 rubles, depending on the service.
Is it possible to clean the old sensor instead of replacing it?
In some cases, if the problem is caused only by oil or dust contamination, the sensor can be cleaned with a special cleaner for carburetors or mass air flow sensors. However, if the electronic part of the sensor has failed, cleaning will not help and replacement will be required.
Does P1108 affect the operation of the air conditioner?
The error does not have a direct effect on the operation of the air conditioner, but in emergency mode the ECU can turn off the air conditioning compressor to reduce the load on the engine if it believes that it is operating under overload due to incorrect pressure data.
Do I need to do an adaptation after replacing the sensor?
In most cases, adaptation occurs automatically after several cycles of starting and operating the engine. However, to fine-tune idle speed settings, it is recommended to perform an adaptation procedure using a diagnostic scanner, especially on models with an electronic throttle.