Engine-CodesHonda – P1128 Honda

P1128 Honda Code - Manifold Absolute Pressure Sensor Signal Lower Than Expected

Quick Answer

The P1128 code for Honda vehicles indicates that the Manifold Absolute Pressure (MAP) sensor signal is lower than what is expected by the Engine Control Module (ECM). Common causes include Faulty MAP sensor, Vacuum leak in the intake manifold, Clogged or dirty MAP sensor. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P1128 Honda indicates Manifold Absolute Pressure Sensor Signal Lower Than Expected.
Common causes
Common causes include Faulty MAP sensor, Vacuum leak in the intake manifold, Clogged or dirty MAP sensor.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Sep 07, 2024
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Code P1128 Honda Description

The P1128 code for Honda vehicles indicates that the Manifold Absolute Pressure (MAP) sensor signal is lower than what is expected by the Engine Control Module (ECM). The MAP sensor plays a crucial role in the engine management system by measuring the pressure inside the intake manifold. This information helps the ECM determine the correct air-fuel mixture for optimal performance and fuel efficiency. When the signal from the MAP sensor is lower than expected, it can lead to various issues with the engine's performance.

OBDII Code P1128 Honda - Manifold Absolute Pressure Sensor Signal Lower Than Expected
P1128 Honda Code - Manifold Absolute Pressure Sensor Signal Lower Than Expected

Common Causes of P1128 Honda

  1. Faulty MAP sensor
  2. Vacuum leak in the intake manifold
  3. Clogged or dirty MAP sensor
  4. Wiring or connector issues related to the sensor

Symptoms of P1128 Honda

  1. Decreased engine power and acceleration
  2. Rough idling or stalling
  3. Hesitation during acceleration
  4. Increased fuel consumption

How to Fix P1128 Honda

  1. Use an OBD-II scanner to retrieve the trouble codes and confirm the P1128 code for the MAP sensor.
  2. Inspect the MAP sensor and its wiring for any visible damage or signs of wear.
  3. Test the MAP sensor using a multimeter to check for proper voltage output.
  4. Replace the MAP sensor if it is faulty or damaged.
  5. Clear the trouble codes and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P1128 Honda

The typical repair costs for addressing a P1128 code on a Honda vehicle can vary depending on the specific cause of the issue. In general, replacing a faulty MAP sensor can cost between $100 and $200 for the part alone. Labor costs at auto repair shops typically range between $80 and $150 per hour, and the total repair cost can add up to around $200 to $400, including parts and labor. However, it is advisable to check with local auto repair shops for more accurate estimates based on your location and vehicle specifications.

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Information for Specific Honda Models

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

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