P0069 Code - Manifold Absolute Pressure/Barometric Pressure Correlation

What Does Code p0069 Mean?

The manifold absolute pressure (MAP) sensor is used to measure engine load. The powertrain control module (PCM) sends the MAP sensor a reference voltage and the sensor varies the voltage according to manifold vacuum. The PCM then uses this information to adjust ignition timing and fuel delivery.



An example of a MAP sensor

Vacuum and pressure are inversely proportional (when vacuum goes up, pressure goes down). Because of this, the MAP sensor is able to measure the pressure in the intake manifold to gauge vacuum. Manifold vacuum is a good indicator of engine load. With the engine off, manifold pressure and atmospheric (barometric) pressure are the same. With the engine running, the movement of the pistons and restriction of the throttle plates create vacuum (reduce pressure). When the engine is under heavy load at wide open throttle (WOT), vacuum is nearly zero. At this time, engine pressure and atmospheric pressure are almost the same.

Depending on the elevation, barometric pressure is usually between 28 to 31 inches of mercury (Hg). By comparison, engine vacuum at sea level is between 17-22 in-Hg. This drops approximately 1 in-Hg for every 1000 ft. of elevation. On some vehicles, when the engine is first started, the PCM looks at the MAP sensor to determine barometric pressure. There are other vehicles, however, that use a dedicated BARO sensor. Others still use a combination BMAP sensor.

There are two types of MAP sensors: analog and frequency. The analog type uses a diaphragm and is connected to the intake manifold by a vacuum line. The sensor monitors the movement of the diaphragm and sends a corresponding analog signal back to the PCM. This type of sensor will have three wires: reference, signal and ground. The other type of MAP sensor is the digital, or frequency type, which produces a digital voltage signal instead of an analog signal.



A cut away of an analog MAP sensor

As was mentioned, some vehicles use an independent BARO sensor. These devices are designed to measure only barometric pressure. The BARO sensor is similar to the MAP sensor in design but is more sensitive to changes in atmospheric pressure.

The code P0069 stands for manifold pressure/barometric pressure correlation. The PCM compares BARO sensor and MAP readings at idle. If the difference between the two is greater than specified, the PCM will set a diagnostic trouble code (DTC).

engine code P0069	P0069 fix	obd P0069	dtc P0069
obd code P0069	obd2 P0069	P0069 car code	diagnostic code P0069
car code P0069	check engine code P0069	fehlercode P0069	P0069 fiat
codigo P0069	codigo falla P0069	P0069 kody błędów	codigo de falla P0069

What are the common causes of P0069 ?

Causes of the P0069 code could include a faulty manifold absolute pressure sensor, a faulty barometric pressure sensor, a fault in the circuitry of either sensor, a faulty Powertrain Control Module, or even a dirty air filter.

A dirty air filter can affect the pressure within the air induction system and the intake manifold, therefore affecting pressure readings of the barometric pressure sensor and the manifold absolute pressure sensor.

What are the symptoms of P0069 ?

The most common symptom, of course, is an illuminated check engine light. Other symptoms may include surging, rough idle, detonation and loss of power.

How do you troubleshoot P0069 ?

To find the right fix, begin your diagnosis at the air intake. Open the air box and look for blockages. A dirty air filter can trigger this code, but so could a blockage further into the intake (so be sure to trace airflow from the airbox all the way to the intake manifold). Many times, simply replacing the filter and clearing the code will resolve a P0069 in your Dodge.

However, if no problems are found and a new air filter does not do the job, then the problem is very likely in the IAT (intake air temperature) sensor.

The IAT sensor is located on the intake, and it records the temperature of the air coming into the intake manifold. If this sensor becomes faulty, it can trigger a MAP BPC and a P0069 trouble code. Replacing the IAT sensor is a relatively simple and straight-forward job, and fortunately the parts are not expensive.

NOTE: P0069 and other codes can also be triggered when an after-market chipset has been installed on a Cummins engine computer. This can cause a short or default in the system, setting off codes like P0069. If your Dodge has after-market chips installed, and if your air filter seems clean, you might try diagnosing this code by first uninstalling the non-OEM chips and resetting the system.

If you find your after-market chip is the cause of the problem, it might make sense to remove it permanently. While some after-market programmers and tools can add real power to your diesel, cheap products that promise big horsepower gains for less than $100 should probably be avoided.

After all, if the after-market could figure out a way to boost horsepower by adding a really cheap computer chip to your diesel, don't you think Dodge or Ram would be putting these chips on at the factory?

IN other words, if it seems too good to be true, it probably is.

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