P1128 1999 Honda Civic 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 1999 Honda Civic 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.
Code P1128 1999 Honda Civic Description
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.
What are the Possible Causes of the DTC P1128 1999 Honda Civic?
- 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 1999 Honda Civic?
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 1999 Honda Civic 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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Frequently Asked Questions about P1128 1999 Honda Civic Code
1. What are common symptoms of OBDII code P1128 on a 1999 Honda Civic?
- Common symptoms include poor engine performance, rough idling, reduced fuel efficiency, and potentially stalling or hesitation during acceleration.
2. What causes the OBDII code P1128 on a 1999 Honda Civic?
- The code P1128 usually indicates a problem with the Manifold Absolute Pressure (MAP) sensor signal being lower than expected, which can be caused by a faulty MAP sensor, vacuum leaks, or issues with the intake system.
3. How can I diagnose the cause of OBDII code P1128 on my 1999 Honda Civic?
- To diagnose the issue, you can start by checking the MAP sensor for proper operation, inspecting for any vacuum leaks in the intake system, and ensuring the intake manifold is tightly sealed.
4. Is it safe to continue driving my 1999 Honda Civic with OBDII code P1128?
- It is not recommended to continue driving with the code P1128 present, as it can lead to further damage to the engine and potentially worsen the symptoms over time.
5. Can I repair OBDII code P1128 on my 1999 Honda Civic myself?
- Depending on your level of automotive knowledge, you may be able to repair the issue yourself by replacing the faulty MAP sensor, fixing any vacuum leaks, or addressing intake system problems. However, professional assistance may be needed for accurate diagnosis and repair.
6. Will resetting the OBDII code P1128 on my 1999 Honda Civic make it go away permanently?
- Simply resetting the code may temporarily clear the warning light, but if the underlying issue causing the code is not addressed, it is likely to reappear once the problem persists.
7. How much does it typically cost to repair OBDII code P1128 on a 1999 Honda Civic at a mechanic?
- The cost of repairing the P1128 code can vary depending on the exact cause of the issue, but it may involve replacing the MAP sensor, fixing vacuum leaks, or other related repairs. Costs can range from $100 to $300 or more.
8. Can a dirty air filter trigger OBDII code P1128 on a 1999 Honda Civic?
- While a dirty air filter may impact engine performance, it is not a common direct cause of the P1128 code. However, ensuring regular air filter maintenance is still important for overall engine health.
9. Will driving in extreme weather conditions affect OBDII code P1128 on a 1999 Honda Civic?
- Extreme weather conditions can potentially exacerbate existing issues related to the MAP sensor or intake system, leading to the triggering of the P1128 code. It is advisable to address any underlying problems regardless of weather conditions.
10. How does the OBDII code P1128 on a 1999 Honda Civic impact emissions and environmental concerns?
- The P1128 code typically indicates a problem affecting the fuel-air mixture, which can lead to increased emissions and environmental pollution. Resolving the issue promptly can help reduce the vehicle's negative impact on the environment.
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