P1158 (Volkswagen, Audi, Skoda, Seat) Manifold absolute pressure (MAP) sensor - unreliable signal
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P1158 – OBD-II Trouble Code Technical Description
Trouble code P1156 indicates an unreliable signal in the manifold absolute pressure (MAP) sensor circuit in Volkswagen, Audi, Skoda, Seat vehicles.
What does the fault code mean P1158?
Trouble code P1158 indicates possible problems with the manifold absolute pressure (MAP) sensor on VW, Audi, Seat and Skoda vehicles. The MAP sensor measures intake manifold absolute pressure and provides information to the engine control module (ECM). This information is important for correct adjustment of the fuel mixture and ignition timing, which in turn affects engine performance. Code P1158 indicates an error in the range or performance of the MAP sensor. This could mean that the sensor is sending incorrect data or is not working properly.
Possible reasons
Trouble code P1158 can be caused by the following reasons:
- Malfunction of the manifold absolute pressure (MAP) sensor: The sensor itself may be damaged or have internal problems such as wear or faulty electronic components.
- Electrical circuit problems: Incorrect connections, opens or shorts in the wires or connectors connecting the MAP sensor to the Engine Control Module (ECM) can cause P1158.
- Engine Control Module (ECM) malfunction: Problems with the ECM, such as software failure or faulty electronic components, can cause the signals from the MAP sensor to be misinterpreted and cause the P1158 code to occur.
- Problems with the vacuum system: Leaks or other problems in the vacuum system that controls the MAP sensor can cause the intake manifold pressure to be incorrectly measured and cause P1158.
Troubleshooting P1158 requires detailed diagnostics to determine and fix the source of the problem.
What are the symptoms of a fault code? P1158?
The following symptoms may occur with DTC P1158:
- Loss of engine power: Improper operation of the manifold absolute pressure (MAP) sensor can result in under- or over-fueling, resulting in loss of engine power.
- Unstable engine operation: P1158 may cause the engine to run rough, shake, or idle rough.
- Increased fuel consumption: Incorrect fuel/air ratio due to malfunctioning MAP sensor may result in increased fuel consumption.
- Other fault codes appear: It is possible that P1158 may be accompanied by other fault codes related to the intake system or engine management.
- Unstable idle: The engine may idle rough or even stall when stopped at a traffic light or in a traffic jam.
- Deterioration of environmental characteristics: An incorrect mixture of fuel and air can lead to increased emissions of harmful substances into the environment.
If you are experiencing the above symptoms and your vehicle is displaying trouble code P1158, it is recommended that you contact a professional to diagnose and repair the problem.
How to diagnose a fault code P1158?
The following steps are recommended to diagnose DTC P1158:
- Checking the MAP sensor connection: Check the condition and connection of the manifold absolute pressure (MAP) sensor connector. Make sure the connector is securely connected and there are no signs of corrosion or damage to the pins.
- Checking the MAP Sensor Status: Remove the MAP sensor from the vehicle and check its condition. Look for signs of wear, damage or corrosion. If the sensor appears damaged or worn, it may need to be replaced.
- Electrical circuit check: Using a multimeter, check the voltage and resistance on the wires connecting the MAP sensor to the engine control module (ECM). Finding opens, shorts, or incorrect resistance may indicate problems with the electrical circuit.
- Checking the vacuum system: Check the condition of the vacuum hoses and connections in the vacuum system that controls the MAP sensor. Leaks in the vacuum system can cause the intake manifold pressure to be measured incorrectly.
- Engine Control Module (ECM) Diagnosis: If necessary, perform diagnostics on the Engine Control Module (ECM) to ensure it is operating properly and is interpreting signals from the MAP sensor correctly.
- Checking other sensors and systems: Sometimes problems with other sensors or intake systems can cause P1158. Check the condition of other sensors and systems such as the oxygen (O2) sensor, fuel injection system and throttle body.
After diagnosing and identifying the problem, it is recommended to carry out the necessary repairs or replace faulty components. If you are not confident in your diagnostic or repair skills, it is better to turn to professionals.
Diagnostic errors
When diagnosing DTC P1158, the following errors may occur:
- Not checking the entire electrical circuit: Some technicians may focus only on checking the MAP sensor itself without paying attention to the condition of the electrical circuit, which can result in problems with the wires or connectors being missed.
- Ignoring other possible causes: Sometimes MAP sensor problems can be caused by other factors, such as vacuum system leaks or faulty engine control module (ECM). Ignoring these possible causes may result in incorrect diagnosis and repair.
- Misinterpretation of results: Incorrect reading or interpretation of diagnostic results, especially when using a multimeter or other equipment, may lead to incorrect identification of the source of the problem.
- Replacement of components without preliminary diagnosticsNote: Replacing the MAP sensor or other components without sufficient diagnostics may be ineffective and cost additional time and money.
- Faulty components after repair: If the problem persists after repair, it may indicate that the repair was not performed correctly or there are other problems that also require attention.
How serious is the fault code? P1158?
Trouble code P1158 can be serious because it indicates problems with the manifold absolute pressure (MAP) sensor or the circuit that controls its operation. If this problem is ignored or handled incorrectly, the following consequences may occur:
- Loss of power and performance: Improper management of the fuel/air mixture can result in loss of engine power and performance, affecting engine performance and efficiency.
- Increased fuel consumption: Improper operation of the MAP sensor may result in improper fuel delivery, which may result in increased fuel consumption.
- Unstable engine operation: Improperly managing the fuel/air mixture can cause the engine to run rough, resulting in engine shaking, rough idling, and other problems.
- Harmful emissions: An incorrect mixture of fuel and air can lead to increased emissions of harmful substances, which will negatively affect the environmental performance of the vehicle.
- Damage to catalyst: If the catalytic converter is operated for a long period of time with the wrong mixture of fuel and air, it can be damaged, leading to costly replacement.
Overall, although P1158 is not fatal, it does require careful attention and repair to prevent more serious problems in the future.
What repair will help eliminate the code? P1158?
Troubleshooting trouble code P1158 may include the following steps:
- Manifold Absolute Pressure (MAP) Sensor Replacement: If the MAP sensor is found to be faulty after diagnosis, it should be replaced with a new one corresponding to the original manufacturer or a high-quality analogue.
- Checking and replacing electrical connections: Check the electrical connections, connectors and wires associated with the MAP sensor. Replace damaged wires or connectors as necessary.
- Diagnosis and replacement of the engine control module (ECM): If the problem is not resolved by replacing the MAP sensor and checking the electrical connections, the problem may be related to the engine control module. In this case, it is necessary to carry out additional diagnostics and, if necessary, replace the ECM.
- Checking the vacuum system: Check the condition of the vacuum hoses and connections in the intake system. Leaks in the vacuum system can cause erroneous signals from the MAP sensor.
- Checking other intake system components: Check the condition and functionality of other intake system components such as the throttle body, air filter and exhaust gas recirculation (EGR) system.
After completing the repair work, it is recommended that you take a test drive and re-diagnosis to ensure that the P1158 trouble code no longer appears and the vehicle operates normally.
