Understanding the P0108 Code: Manifold Absolute Pressure/Barometric Pressure Circuit High Input

Ever been on a peaceful drive when, suddenly, your vehicle’s check engine light flickers on, and you find yourself dealing with the ominous P0108 code? Don’t fret! This article will guide you through the labyrinth of this auto trouble code, its causes, symptoms, and solutions. Let’s dive in, shall we?

What is the P0108 Code?

The P0108 code is a diagnostic trouble code (DTC) that indicates a problem with the Manifold Absolute Pressure (MAP) sensor or the Barometric Pressure Circuit. This code specifically means that the circuit is giving a higher input signal than expected by the vehicle’s Engine Control Unit (ECU). In simple terms, your car’s computer thinks the MAP sensor is ‘shouting’ too loudly.

Causes of the P0108 Code

There are several potential culprits behind the P0108 code. These could include a faulty MAP sensor, shorted wiring in the sensor circuit, a problem with the Powertrain Control Module (PCM), or even a vacuum leak in the intake manifold.

Symptoms of the P0108 Code

Some symptoms that might suggest the P0108 code has been triggered include poor fuel economy, rough idling, difficulty starting the engine, and a lack of power during acceleration. The most obvious sign, of course, is the illumination of the check engine light.

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Importance of Manifold Absolute Pressure (MAP) Sensor

The MAP sensor plays a vital role in how your engine performs. It’s a key component in maintaining the delicate balance between air and fuel in your engine.

How the MAP Sensor Works

The MAP sensor measures the absolute pressure inside the intake manifold and relays this information to the ECU. Based on this data, the ECU adjusts the fuel injection and ignition timing for optimal engine performance.

Role of the MAP Sensor in Engine Performance

By providing accurate air pressure readings, the MAP sensor ensures that your engine maintains the optimal air-fuel mixture. This not only helps in achieving the best possible fuel economy but also ensures that the engine runs smoothly.

Diagnosing and Fixing the P0108 Code

Before you can fix the P0108 code, you first need to diagnose the issue accurately. This process will require some specific tools and a methodical approach.

Tools Needed

To diagnose the P0108 code, you’ll need a digital multimeter, a scanner tool compatible with your vehicle, and a basic toolkit for accessing and testing components.

Step-by-step Diagnostic Process

Start by using your scanner tool to confirm the P0108 code. Next, visually inspect the MAP sensor and its wiring for any obvious signs of damage or disconnection. Use the digital multimeter to check for proper voltage and resistance within the MAP sensor circuit. It’s important to consult your vehicle’s repair manual during this process for specific testing procedures and expected results.

Solutions and Repair Process

Based on your diagnostic results, the solution might involve replacing a faulty MAP sensor, repairing a leak in the intake manifold, or addressing issues with the wiring or PCM. Always clear the code after the repair and run the car to ensure the check engine light doesn’t come back on.

Preventing the P0108 Code

Prevention is always better than cure, especially when it comes to vehicle maintenance.

Regular Maintenance

Regular maintenance is key to preventing issues like the P0108 code. This includes timely oil changes, air filter replacements, and regular inspections of the engine components.

Spotting Early Signs

Pay attention to the early signs. If your vehicle starts showing symptoms like rough idling, poor fuel economy, or lack of power during acceleration, it’s a good idea to run a diagnostic check.


The P0108 code might seem daunting, but understanding its causes and knowing how to diagnose and fix it can save you a trip to the mechanic, not to mention a considerable amount of money. Remember, regular maintenance and staying alert to your vehicle’s performance are key to preventing this and other engine codes.

Frequently Asked Questions

What does the P0108 code mean?

  1. The P0108 code indicates a high input signal in the Manifold Absolute Pressure or Barometric Pressure Circuit.

Can I drive my car with the P0108 code?

  1. While your vehicle may still run with the P0108 code, it’s not advisable to ignore it. The issue can lead to poor fuel economy, potential damage to the engine, or a breakdown.

How is the P0108 code diagnosed?

  1. The P0108 code is diagnosed using a scanner tool and a digital multimeter, along with a visual inspection of the MAP sensor and related components.

How do I fix the P0108 code?

  1. Fixing the P0108 code can involve replacing a faulty MAP sensor, repairing a leak in the intake manifold, or addressing issues with the circuit’s wiring or the PCM.

How can I prevent the P0108 code?

  1. Regular vehicle maintenance and paying attention to early signs of trouble can help prevent the P0108 code from appearing.