The amount of intake air flow must be inputted to PCM in order to determine the fuel injection quantity. MAPS(Manifold Absolute Pressure) calculates the amount of air indirectly as measuring the pressure inside of intake manifold. This mechanism is also called Speed-Density Type.MAPS transfers analog output signal which is proportional to the change of intake manifold pressure, then, with this signal and RPM, PCM calculates the amount of intake air flow. MAPS is mounted on surge tank to measure the pressure inside of intake manifold, and it consists of a piezo electric element and hybrid IC which amplifies output signal from the element. A piezo electric element is a sort of a diaphragm using piezo electric effect. One side of the diaphragm is surrounded with vacuum chamber while intake pressure is applied to the other side. Thus, signals are output by the transformation of diagphragm according to the change of pressure inside of intake manifold.
Checking output signals of MAPS under detecting condition, if an output signal is intermittently above 4.5V ., PCM sets P1106.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Monitor the signal of MAP sensor | ● Poor connection ● Short to battery in signal circuit ● Open in groundcircuit ● Faulty MAPS ● Faulty PCM |
Enable Conditions | Case 1 | ● No TPS Active Fault Present ● Engine Running Time > 10sec. ● Engine Speed ≤ 2500rpm ● Throttle Position ≤ 30% |
Case 2 | ● No TPS Active Fault Present ● Engine Running Time > 10sec. ● Engine Speed > 2500rpm ● Throttle Position ≤ 40% | |
Threshold value | ● Intermittently MAP Signal > 4.5V | |
Diagnosis Time | ● Continuous | |
MIL On Condition | ● DTC only(NO MIL ON) |
Pressure(kPa) | 20 | 35 | 60 | 95 | 101.32 |
Voltage(V) | 0.789 | 1.382 | 2.369 | 3.75 | 4 |
Allowable error(V) | ± 0.045 |
