[SOLVED] P1128 Code: Closed Loop Fueling Not Achieved Bank 1 – How To Fix It!

The automobile fault code P1128 indicates a problem with the fuel delivery system, MAP sensor or wiring connectors, O2 sensor wiring or connectors, engine mechanical system, or a faulty PCM.

The symptom is an illuminated Engine Light or Service Engine Soon Warning Light. To fix this issue, visually inspect the wiring harness and connectors, checking for any damage or corrosion. Look for broken, bent, pushed out, or corroded connector pins.

The repair time for this fault code is estimated at 1.0.

It is important to address this issue promptly to prevent further damage to the vehicle.

Repair Importance Level10.0 (Out of 10)
Estimated Repair TimeApproximately 1.0 hour
Repair Difficulty Level6.67 (Out of 10)

If you see the Engine Light ON or the Service Engine Soon Warning Light, it could be a sign of the p1128 fault code.

  • The symptoms of the automobile fault code P1128 include the Engine Light being ON or the Service Engine Soon Warning Light being illuminated.

The automobile fault code p1128 can be caused by issues with the fuel delivery system, MAP sensor or wiring connectors, O2 sensor wiring or connectors, engine mechanical system, or a faulty PCM.

  • The fault code P1128 can be caused by issues with the fuel delivery system, problems with the Manifold Absolute Pressure (MAP) sensor or its wiring connectors, faults in the O2 sensor wiring or connectors, malfunctions in the engine mechanical system, and a faulty Powertrain Control Module (PCM).

To fix the automobile fault code p1128, start by visually inspecting the wiring harness, connectors, and components for any damage or corrosion.

  • To fix the automobile fault code p1128, start by checking the possible causes mentioned above.
  • Then, visually inspect the wiring harness and connectors for any damage.
  • Look for broken, bent, pushed out, or corroded pins in the connectors.
  • This fix should take approximately 1.0 hour.

The factors influencing the diagnosis and fixing cost of automobile fault code p1128 are the estimated repair time of 1.0 hour and the average hourly rate charged by auto repair shops, which ranges between $75 and $150.

The P1128 fault code indicates that the vehicle’s Powertrain Control Module (PCM) has detected a situation where the vehicle has stayed in open loop fuel control for a longer period than expected. This occurs when the vehicle fails to achieve closed loop operation within a specific timeframe after starting up. The code specifically refers to the inability to achieve closed loop fueling on a particular bank of the engine.

In simpler terms, the PCM is responsible for monitoring and adjusting the fuel mixture in the engine.

Normally, the engine operates in closed loop mode, where the PCM uses input from various sensors to optimize fuel delivery.

However, if the engine remains in open loop mode for too long after starting, it means that the PCM is unable to achieve the desired fueling conditions. This can lead to inefficient fuel consumption and potentially affect the vehicle’s performance.

What are the possible causes of the p1128 fault code and how can they be identified?

If you’re seeing the p1128 fault code with the engine light on, it could be due to a few different causes. It might be an issue with the fuel delivery system, the MAP sensor or its wiring connectors, the O2 sensor wiring or connectors, the engine mechanical system, or even a faulty PCM. To identify the exact cause, visually inspect the related wiring harness and connectors. Look for any damaged components and check for broken, bent, pushed out, or corroded connector pins. Don’t forget to check the “Possible Causes” listed above for further guidance.

How can I visually inspect the wiring harness and connectors to fix the p1128 fault code?

If you’re dealing with the p1128 fault code and your engine light is on, it’s time to take a closer look at the wiring harness and connectors. This code can be caused by issues with the fuel delivery system, MAP sensor or wiring connectors, O2 sensor wiring or connectors, engine mechanical system, or a faulty PCM. To fix it, visually inspect the wiring harness and connectors for any damage or issues. Check for broken, bent, pushed out, or corroded pins on the connectors. Don’t forget to also check the other possible causes listed above.

What steps should I take to check for damaged components and connector issues when troubleshooting the p1128 fault code?

To troubleshoot the p1128 fault code, start by checking for damaged components and connector issues. Visually inspect the wiring harness and connectors related to the fuel delivery system, MAP sensor, O2 sensor, and engine mechanical system. Look for any broken, bent, pushed out, or corroded pins in the connectors. This will help identify any issues that may be causing the engine light to come on.

p1128 error fault code explained

If your engine light is on and you’re dealing with a P1128 fault code, it could be due to issues with the fuel delivery system, MAP sensor or wiring connectors, O2 sensor wiring or connectors, engine mechanical system, or a faulty PCM.

To fix it, visually inspect the wiring harness and connectors, check for damaged components, and look for any broken, bent, pushed out, or corroded connector pins.

Scroll to Top