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 outputted by the transformation of diagphragm according to the change of pressure inside of intake manifold.
Checking output signals of MAPS every 60 sec. under detecting condition, if an output signal is below 0.25V for more than 2 sec., PCM sets P1107.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● This code detects a intermittent short to low or open in either the signal circuit or the MAP | ● Poor Connection ● Open or Short to ground in Power Circuit ● Open or short to ground in Signal Circuit. ● Faulty MAPS ● Faulty PCM |
Enable Conditions | Case 1 | ● No TPS Active Fault Present ● No TPS Short Fail Criteria Met ● Ignition Voltage ≥ 11V ● Engine Speed < 1000rpm ● Throttle Position ≤ 0% |
Case 2 | ● No TPS Active Fault Present ● Ignition Voltage ≥ 11V ● Engine Speed > 1000rpm ● Throttle Position > 30% | |
Threshold value | ● MAP signal < 0.25V | |
Diagnosis Time | ● Continuous (More than 2 sec. failure for every 60 sec. test) | |
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 |
