|Code||Fault Location||Probable Cause|
|P112F|| P112F – Manifold Absolute Pressure to Throttle Angle – Too High (Bank 1) (BMW) |
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Manufacturer Specific Definitions for P112F
|Bmw||P112F - Manifold Absolute Pressure to Throttle Angle - Too High (Bank 1)|
Table of Contents
- What Does Code P112F Mean?
- Where is the P112F sensor located?
- What are the common causes of code P112F?
- What are the symptoms of code P112F?
- Get Help with P112F
What Does Code P112F Mean?
OBD II fault code P112F is a manufacturer-specific trouble code that is defined by carmaker BMW as P112F – “Manifold Absolute Pressure to Throttle Angle – Too High Bank 1 “ and is set when the DME (Digital Motor Electronics) detects an implausible or incorrect signal voltage from the MAP (Manifold Absolute Pressure) sensor, given the current operating conditions or actual throttle position. Note that “DME” is BMW-speak for “Powertrain Control Module” and that Bank 1 refers to the bank of cylinders on V-type engines that contains cylinder #1.
SPECIAL NOTES: It is important to note that the definition and diagnostic/repair implications of code P112F on different BMW models vary, based on the particular software version in use by the DME. Therefore, we strongly recommend that you visit this resource for more information about the code setting parameters and repair options that apply to the DME software version in use by an affected vehicle. Nonetheless, since code P112F essentially indicates a miscorrelation between the input signals of the throttle body and the MAP (Manifold Absolute Pressure) sensor, this article will discuss code P112F as it applies to DMEs using software version DME8FF_R. END OF SPECIAL NOTES.
On vehicles that use MAP (Manifold Absolute Pressure) sensors, the changing negative pressure (vacuum) in the intake manifold during engine operation is a critical parameter that largely defines fuel delivery and ignition timing strategies. Put differently, this means that since the engine speed and throttle plate positions have a direct bearing on the level of the vacuum in the intake manifold at all times, the actual manifold vacuum at any given moment, as opposed to the desired manifold vacuum at any given time, serves as the starting point for almost all engine and fuel management functions.
As a practical matter, MAP sensors are relatively simple devices that use resistive elements of various types to change a low electrical current as the pressure on the resistive element changes. In all cases, the low current is known as a reference voltage, which has an intensity of 5V is supplied by the DME. Thus, as the vacuum in the intake manifold changes during normal engine operation, the increasing or decreasing vacuum causes less or more current to pass through the resistive element, which changes the DME interprets as changes in the manifold vacuum.
We need not delve into all the factors that influence intake manifold vacuum values here, but suffice it to say that since the sudden opening or closing of the throttle plate is the single biggest factor that causes steep rises and dips in the manifold vacuum, the DME correlates the position of the throttle plate with input data from the MAP sensor for several reasons, including, but not limited to the following-
- verifying that the actual manifold vacuum (as reported by the MAP sensor) matches the desired or calculated manifold vacuum as a function of the throttle position
- maintaining a stoichiometric air/fuel mixture based on the position of the throttle plate and the actual manifold vacuum, which in this context, in an indicator of the volume of air flowing through the intake manifold
- verifying that the throttle position (as reported by the throttle position sensor) correlates with the actual volume of air flowing through the intake manifold. Note that in this context, the desired or calculated manifold vacuum serves as a reference value the DME uses to a) judge the accuracy of the MAP sensor and b) measure the correlation between the actual throttle position and the reported intake manifold vacuum
From the above, it should be clear that the relationship between the intake manifold vacuum and the throttle position is an exceedingly complex one that involves many interrelated engine and fuel management functions and processes. Therefore, when the actual manifold vacuum is reported to exceed a maximum allowable threshold relative to the position of the throttle plate, the DME will recognize that it cannot manage one or more engine management processes effectively, and it will set code P112F and illuminate a warning light as a result.
Where is the P112F sensor located?
In this image, the small yellow square indicates the position of the MAP sensor on a BMW N54 engine. Note that while the sensor is easy to access on this model, the actual locations of MAP sensors on other engine variants vary somewhat. Therefore, we strongly suggest that you research the location of the MAP sensor on an affected vehicle to prevent a misdiagnosis and the possible unnecessary replacement of the wrong or unrelated parts.
What are the common causes of code P112F?
Depending on the DME’s software version, some common causes of code P112F could include or more of the following-
- Intake air temperature greater than the lower limit value and lower than the upper limit value:
- – Lower limit value: between -30°C and -20°C (depending on variant)
- – Upper limit value: between 120°C and 180°C (depending on the version)
- Coolant temperature greater than a maximum allowable limit (Limit depends on the software version in use)
- Ambient pressure higher than a maximum allowable value (Value depends on the software version in use)
- Engine speed is greater than the lower limit value and lower than the upper limit value:
- -lower limit value: between 0 rpm and 650 rpm (Depending on the software version)
- -upper limit value: between 0 rpm and 9000 rpm (Depending on the software version)
- Engine speed variation greater than the limiting value (This value depends on the software version in use)
- Fluctuation of the engine load greater than the limiting value (This limit depends on the software version in use)
NOTE: Due to the large number of possible causes of this code that depends on the software version in use in the DME, we do not recommend that non-professional mechanics attempt a diagnostic procedure for this code since a BMW dealer-grade scan tool is required to determine which software version the DME is programmed with.
What are the symptoms of code P112F?
The only symptom this code will produce with software version DME8FF_R will be a stored trouble code and an illuminated warning light.
It is important to note that if any other symptoms, and especially drivability symptoms are present, the affected vehicle should be scanned with factory-grade diagnostic equipment to extract possible fault codes that are not accessible even to high-end generic scan tools.
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