The amount of intake air flow must be inputted to PCM in order to determine the fuel injection quantity. To measure the pressure inside of intake manifold, MAFS is used at idle and MAPS is required at accelerating. MAPS(Manifold Absolute Pressure) calculates the amount of air indirectly as measuring the pressure inside of intake manifold. This mechanism is alsl 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.
DTC DESCRIPTION
If the signal output of MAP sensor is stuck under enable conditions, PCM determines that a fault exists and a DTC is stored. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
DTC DETECTING CONDITION
Item
Detecting Condition
Possible cause
DTC Strategy
●
Monitor the MAP sensor's signal
●
Faulty MAPS
Enable Conditions
●
No Disabling Fault Present
●
Shutdown time ＞ 20 minutes
●
Engine running
Thresh old value
●
The difference between the signal at key-on and the signal at engine start ＜0.5 kPa
Diagnosis Time
●
For 3 seconds out of 5 seconds
MIL On Condition
●
2 driving cycles
SIGNAL WAVEFORM
SPECIFICATION
Pressure(kPa)
20
35
60
95
101.32
Voltage(V)
0.789
1.382
2.369
3.75
4
Tolerance(V)
± 0.045
SCHEMATIC DIAGRAM
MONITOR DTC STATUS
1.
Check DTC Status
(1)
Connect scantool to Data Link Connector(DLC).
(2)
IG "ON".
(3)
Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F4(DTAL) to check DTC's information from the DTCs menu
(4)
Read "DTC Status" parameter.
(5)
Is parameter displayed "Present fault"?
▶ Go to "Component Inspection" procedure.
▶ Fault is intermittent caused by PCM memory was not cleared after repair. Erase DTC and drive the vehicle to satisfy the enable codition then,go to " Component Inspection" procedure.
COMPONENT INSPECTION
1.
Check MAPS Performance
(1)
IG "OFF" and install scatool.
(2)
Connect probe to MAPS and TPS to check signal waveform by using oscilloscope function.
(3)
ENG "ON" and monitor signal waveform during accelleration and decelleration.
■ Specificaton :
Pressure(kPa)
20
35
60
95
101.32
Voltage(V)
0.789
1.382
2.369
3.75
4
Tolerance(V)
± 0.045
(4)
Is the measured signal waveform(MAP/TPS Rationality) O.K ?
▶ Go to "Verification of Vehicle Repair" procedure.
▶ Substitute with a known - good MAPS and check for proper operation.
▶ If the problem is corrected, replace MAPS and go to "Verification of Vehicle Repair" procedure.
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1.
Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode
2.
Press F4(DTAL) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions
3.
Read "DTC Status" parameter
4.
Is parameter displayed "History(Not Present) fault"?
▶ System performing to specification at this time. Clear the DTC.
