Diagnostic Trouble Code (DTC): P1108 - Barometric Pressure (BARO) Sensor - Circuit/Voltage High

P1108 code definition

The P1108 code is a manufacturer-specific powertrain code related to fuel and air metering. In this case it means that the engine control module (ECM) has detected a fault with the barometric pressure (BARO) sensor signalling a higher than normal voltage signal. It may also be due to a fault with the Manifold Absolute Pressure (MAP) sensor.

As the P1108 code is manufacturer specific, the following manufacturers may have specifics regarding their specific makes including, but not limited to Acura, General Motors, Honda, Isuzu, Jaguar, and Saab.

Codes related to the P1108 include:

• P0068: MAP/MAF – Throttle Position Correlation
• P0105: Manifold Absolute Pressure/Barometric Pressure Circuit
• P0106: Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance Problem
• P0107: Manifold Absolute Pressure/Barometric Pressure Circuit Low Input
• P0108: Manifold Absolute Pressure/Barometric Pressure Circuit High Input
• P0109: Manifold Absolute Pressure/Barometric Pressure Circuit Intermittent
• P0316: Engine Misfire Detected on Startup (First 1000 Revolutions)
• P2073: Manifold Absolute Pressure/Mass Air Flow - Throttle Position Correlation at Idle
• P2074: Manifold Absolute Pressure/Mass Air Flow - Throttle Position Correlation at Higher Load
• P2226: Barometric Pressure Circuit
• P2227: Barometric Pressure Circuit Range/Performance
• P2228: Barometric Pressure Circuit Low
• P2229: Barometric Pressure Circuit High
• P2230: Barometric Pressure Circuit Intermittent

What the P1108 code means

A code P1108 will be stored when the Manifold Absolute Pressure (MAP) or BARO sensor sends the ECM a higher than normal voltage signal. The MAP sensor is used to read the incoming air charge to an engine. When the BARO sensor reports a voltage higher than predetermined manufacturer parameters, a code can be stored.

What causes the P1108 code?

Several problems may cause a P1108 code including:

• Damaged, corroded, open, or shorted electrical wiring and related connectors
• Damaged or defective MAP sensor
• Damaged or defective BARO sensor
• Incorrect software installed on ECM
• Damaged or defective ECM

What are the symptoms of the P1108 code?

Symptoms of a P1108 code may include:

• Check engine or warning light may illuminate
• Vehicle may hesitate during acceleration
• Vehicle may idle roughly or “stumble” during acceleration
• Decrease in fuel economy

How does a mechanic diagnose the P1108 code?

A mechanic may use several methods to diagnose a P1108 trouble code, including:

• Utilize an OBD-II scanner to check for a stored P1108 trouble code
• Visually check for damaged, corroded, open, or shorted electrical wiring and related connectors
• Diagnose any engine misfire codes, manifold air pressure (MAP) codes, or mass airflow codes
• Check to see if the issue is in the mass airflow system circuitry
• Determine if there is a problem with unmetered air entering the engine
• Check if there is insufficient air supply to the engine
• Check if the fuel conditions are correct (not too rich or too lean)
• Determine if there is a clogged filter element
• Check for a damaged or defective air inlet pipe
• Check for a clogged catalytic converter
• Check for any possible vacuum leaks
• Check for power and ground signals to the MAP or BARO sensors
• Test sensors against manufacturer's recommendations
• Test all circuits for continuity and resistance
• Inspect hot wire of the mass air flow for signs of damage

Common mistakes when diagnosing the P1108 code

At times, it is possible to believe the MAP or BARO sensors are the culprit of a P1108 code, however before replacing these more expensive components, it is recommended to seek the assistance of a professional to fully diagnose wiring and electrical circuitry for possible damage and repair prior to sensor replacement.

How serious is the P1108 code?

Because a vehicle’s safe driving operation most likely will be impacted due to faults that store a P1108 code, this code is considered a potentially serious code. When this code appears, it is recommended to immediately take your vehicle to your local service center or mechanic for repair and diagnosis.

What repairs can fix the P1108 code?

Several repairs can fix a P1108 trouble code and include:

• Repair any damaged, corroded, open, or shorted electrical wiring and related connectors
• Fully repair any engine misfire codes, manifold air pressure (MAP) codes, or mass airflow codes
• Repair any MAF system circuitry issues
• Repair unmetered air coming into the engine or an insufficient air supply
• Repair or replace clogged air filter
• Repair or replace damaged or defective air inlet pipe
• Clear any clogged catalytic converter(s)
• Repair any vacuum leaks or replace damaged or defective hoses
• Replace damaged or defective MAP sensor
• Replace damaged or defective BARO sensor
• Repair or replace damaged or defective circuitry
• Clean debris from mass air flow hot wire
• Replace damaged or defective ECM
• Clear all codes, test-drive the vehicle, and rescan to see if any codes reappear

Need help with a P1108 code?

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