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.
DTC DESCRIPTION
Checking output signals of MAPS every 5 sec. under detecting condition, if an output signal is above 4.5V for more than 2.5 sec., PCM sets P0108. 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
●
This code detects a continuous short to high in either the signal circuit or the MAP sensor
●
Connecting condition
●
Short to battery in Signal Circuit
●
Open in Ground Circuit
●
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
●
MAP Signal 〉4.5V
Diagnosis Time
●
Continuous
(More than 2.5 seconds failure for every 5 seconds test )
MIL On Condition
●
2 Driving Cycle
SIGNAL WAVEFORM AND DATA
Comparing MAPS and TPS, The signals of MAPS and TPS increasess and decrease simultaneously.
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 "Terminal and connector inspection" procedure.
▶ Fault is intermittent caused by poor contact in the sensor’s and/or PCM’s connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
TERMINAL AND CONNECTOR INSPECTION
1.
Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3.
Has a problem been found ?
▶ Repair or replace if necessary and go to "Verification of Vehicle Repair" procedure
▶ Go to "Power Circuit Inspection" procedure.
POWER CIRCUIT INSPECTION
1.
IG "OFF"
2.
Disconnect MAPS connector
3.
IG "ON"
4.
Measure the voltage between terminal 2 of MAPS harness connector and ground.
Specification : Approx. 5V
5.
Is the measured voltage within specification ?
▶ Go to "Ground Circuit Inspection" procedure.
▶ If the voltage is over 5.1V, check short to battery in harness.
▶ Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
GROUND CIRCUIT INSPECTION
1.
IG "OFF".
2.
Disconnect MAPS connector.
3.
IG "ON" ＆ ENG "OFF"
4.
Measure the voltage between terminal 2 of MAPS harness connector and chassis ground.
5.
Measure the voltage between terminal 2 and 4 of MAPS harness connector.
Specification : "A" - "B" = : Approx. below 200mV
6.
Is the measured voltage within specification ?
▶ Go to "Signal Circuit Inspection" procedure.
▶ Repair contact reistance or open in harness and then go to "Verification of Vehicle Repair" procedure.
SIGNAL CIRCUIT INSPECTION
1.
IG "OFF"
2.
Disconnect MAPS and PCM connector.
3.
Measure resistance between terminal 1 and 2 of MAPS harness connector.
Specification : Infinite
4.
Is the measured resistance within specification ?
▶ Go to "Component Inspection" procedure.
▶ Repair short to battery in harness and then go to "Verification of Vehicle Repair" procedure.
COMPONENT INSPECTION
1.
MAPS performance test
(1)
IG "OFF"
(2)
Connect scantool to Data Link Connector(DLC) and select "Oscilloscope" then, connect probes to output signal lines of MAPS and TPS.
(3)
Start engine and monitor the waveforms during accelerating and decelerating.
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 waveform displayed correctly?(Compare the response time of TPS and MAPS)
▶ Go to "Check PCM".
▶ After replacing MAPS with new one, if it operates normally, replace MAPS and go to "Verification of Vehicle Repair".
2.
Check PCM
(1)
IG "OFF" disconnect MAPS connector
(2)
Connect Scantool and IG "ON" & ENG "OFF"
(3)
Select simulation function on scantool.
(4)
Simulate voltage at terminal 1 of MAPS harness connector.
(5)
Does the output voltage response to the change of signal by simulation?
▶ Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace if necessary and go to "Verification of Vehicle Repair" procedure
▶ Substitute with a known - good PCM and check for proper operation. If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.
note
There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by PCM.Before or after testing PCM on the vehicle, use this function to reuse the PCM on the others
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.
