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Dodge Durango P1128: Meaning, causes and possible solution

 

P1128 Dodge Durango

P1128 is a manufacturer-specific problem code. In the case of the Dodge Durango, it indicates that the engine has not entered a fuel “closed loop” on the bank 1 side.

If other codes appear with P1128, start with them, as this code does NOT indicate what caused the engine to fail to run in a closed loop.

The most common cause of P1128 is a bad sensor (usually a bad oxygen sensor).


P1128 Definition: Closed Loop Power – Not Achieved – Bank 1

P1128 has the same meaning for all vehicles manufactured by Chrysler. This is the three-part definition of P1128 in the Dodge Durango:

Closed loop feeding

When you start your Durango, there are some factory air/fuel mixture settings that work with tables. This is open open-circuit fuel supply.

As data is received from the various engine monitoring sensors (O2, MAP, ECT, etc…), the Powertrain Control Module (PCM) uses it to optimize the air/fuel ratio over time. real. This is called closed-loop feeding.

has not been achieved

The engine remains in closed-loop operation, usually due to a failure in one of the sensors mentioned above.

Bank 1

Bank 1 is the engine side of your Dodge Durango with the first cylinder. You only have to worry about this if the engine is a “V” type with two cylinder heads. If there is only one cylinder head, you don’t have to worry about locating bank 1.

On Dodge engines with two banks, the side with the first cylinder may change depending on your engine. As a general rule, bank 1 is on the passenger side of the engine in rear-wheel drive cars and trucks. On front-wheel drive vehicles, it will be on the opposite side when looking at the engine accessories. You can use this aa1car guide to check your engine.


Dodge Durango P1128 Symptoms

Since P1128 tells you that your Durango vehicle has not entered closed circuit, but not WHY it has not, symptoms may vary. Here are the most common ones:

  • check engine light
  • Reduced fuel consumption
  • Stuttering or misfires
  • Difficulty starting
  • Fuel smell

Dodge Durango P1128: Diagnosis

P1128 Diagnostic

Check other codes

The first thing to do to diagnose P1128 on the Durango is to check for other codes. It is doubtful that you will get this code without another one present.

P1128 tells you that the PCM is left in open loop mode. There should be another code that indicates what the problem is (such as P0136).

oxygen sensors

A faulty O2 sensor is probably the most common cause of P1128.

Oxygen sensors measure exhaust gases and are vital for the PCM to operate in a closed loop.

A bad oxygen sensor on the bank 1 side is one of the most common causes of P1128. If you have an engine with two banks and a trouble code related to the oxygen sensor, you can swap the codes for bank 1 and bank 2 to see if it “jumps” to the other bank.

O2 sensor wiring

Often, a wiring problem can cause an O2 sensor to stop reporting correctly. Cracked, shorted, burned, or damaged wiring can cause it to stop communicating with the PCM.

MAP/MAF Sensor

The Manifold Absolute Pressure (MAP) sensor measures the air entering your Durango’s engine. The PCM cannot go into a closed loop if it does not calculate airflow correctly.

engine coolant sensor

A faulty ECT sensor can cause P1128 on MOPARS. The PCM adjusts the air/fuel mixture when the vehicle warms up. You cannot enter a closed circuit if you do not know that the vehicle is hot.

Other causes of P1128

  • If there are no other codes, suspect a vacuum or exhaust leak.
  • Faulty idle air temperature sensor
  • Fuel pressure (too high or too low)
  • Serious engine mechanical failure
  • Defective PCM (very rare)

Conclusion

A bad oxygen sensor is the most likely cause of P1128 on the Dodge Durango. But there are also many other causes. If there are other codes, they can help you reduce it.

 

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