AutoCodes – Acura – P1128 Acura

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

Quick Answer

The Manifold Absolute Pressure (MAP) sensor senses manifold absolute pressure (vacuum) and converts it into electrical signals. Common causes include Engine mechanical condition, Faulty Manifold Absolute Pressure (MAP) sensor, Manifold Absolute Pressure (MAP) sensor harness is open or shorted. 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 Acura indicates Manifold Absolute Pressure Sensor Signal Lower Than Expected.
Common causes
Common causes include Engine mechanical condition, Faulty Manifold Absolute Pressure (MAP) sensor, Manifold Absolute Pressure (MAP) sensor harness is open or shorted.
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.
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Code Popularity 7,105
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Apr 26, 2019
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Code P1128 Acura Description

The Manifold Absolute Pressure (MAP) sensor senses manifold absolute pressure (vacuum) and converts it into electrical signals. The MAP sensor outputs low signal voltage at high-vacuum (idling) and high signal voltage at low-vacuum (throttle valve wide open).
The Engine Control Module (ECM) compares a predetermined MAP value at a given throttle position and manifold absolute pressure to the output voltage value of the MAP sensor.
If the MAP sensor outputs lower voltage than expected, the ECM detects a malfunction and stores a DTC.
OBDII Code P1128 Acura - Manifold Absolute Pressure Sensor Signal Lower Than Expected - AutoCodes.com
P1128 Acura Code - Manifold Absolute Pressure Sensor Signal Lower Than Expected

What are the Possible Causes of the DTC P1128 Acura?

  • Engine mechanical condition
  • Faulty Manifold Absolute Pressure (MAP) sensor
  • Manifold Absolute Pressure (MAP) sensor harness is open or shorted
  • Manifold Absolute Pressure (MAP) sensor circuit poor electrical connection

How to Fix the DTC P1128 Acura?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1128 Acura code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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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.

Frequently Asked Questions about P1128 Acura Code

What does the OBDII code P1128 mean for an Acura?

The code P1128 indicates that the Manifold Absolute Pressure (MAP) sensor is detecting a signal that is lower than expected, which may affect engine performance.

What are the common symptoms of code P1128 in an Acura?

Symptoms may include poor acceleration, rough idling, reduced fuel efficiency, and possibly an illuminated check engine light.

What causes the P1128 code to appear?

Common causes include a faulty MAP sensor, vacuum leaks, damaged wiring or connectors, or issues with the engine control module (ECM).

Can a dirty air filter trigger the P1128 code?

Yes, a clogged air filter can restrict airflow, potentially leading to inaccurate readings from the MAP sensor.

How do you diagnose the P1128 code in an Acura?

Diagnosis typically involves inspecting the MAP sensor, checking for vacuum leaks, testing sensor voltage, and examining the wiring and connectors for damage.

Is it safe to drive with the P1128 code active?

While the vehicle may still be drivable, operating with this code can lead to reduced performance and potential engine damage if left unresolved.

How can you fix the P1128 code?

Repairs may include replacing the MAP sensor, repairing damaged wiring or connectors, fixing vacuum leaks, or cleaning the throttle body.

How much does it cost to repair the P1128 code?

Repair costs vary depending on the issue, but replacing a MAP sensor typically costs between $100 and $300, including parts and labor.

Can an aftermarket MAP sensor cause the P1128 code?

Yes, a low-quality aftermarket MAP sensor may provide inaccurate readings, potentially triggering this code.

How often should the MAP sensor be replaced to avoid issues like P1128?

MAP sensors are generally designed to last the lifetime of the vehicle but should be inspected and replaced if they show signs of failure.

Discuss the causes and fixes for P1128 Acura OBDII Code

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