P0102
COMPONENT LOCATION
GENERAL DESCRIPTION
MAF Sensor is an air mass flow meter, which operates on the principle of hot film anemometry. A heated element is placed within the air stream, and maintained at a constant temperature above the air temperature. The amount of electrical power required to maintain the heated element at the proper temperature is a direct function of the flow rate of the air mass past the element. ECM/PCM uses this information to determine the injection duration and ignition timing for the desired air/fuel ratio.
DTC DESCRIPTION
If signal output voltage or intake air mass is less than the minimum threshold value under specified conditions, ECM/PCM sets P0102.
DTC DETECTING CONDITION
SCHEMATIC DIAGRAM
(A/T)
(M/T)
MONITOR SCANTOOL DATA
1. Connect scantool to DLC(Data Link Cable).
2. Warm up the engine to normal operating temperature.
3. Monitor "MAFS" parameter on scantool.
4. Is the "MAFS" parameter displayed correctly?
YES
> Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM/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.
NO
> Go to "Terminal and Connector Inspection" 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?
YES
> Repair as necessary and go to "Verification of vehicle Repair" procedure.
NO
> Go to "Power Circuit Inspection" procedure.
POWER CIRCUIT INSPECTION
1. IG "OFF".
2. Disconnect MAFS connector.
3. IG "ON" & ENG "OFF"
4. Measure voltage between terminal 2 of MAFS harness connector and chassis ground.
Specification : B+
5. Is the measured voltage within specification?
YES
> Go to "Signal Circuit Inspection" procedure.
NO
> Repair or replace as necessary and then, go to "Verification of Vehicle Repair"procedure.
SIGNAL CIRCUIT INSPECTION
1. Check open in harness.
(1) IG "OFF".
(2) Disconnect MAFS and ECM/PCM connector.
(3) Measure resistance between terminal 3 of MAFS harness connector and terminal 10/C01-1 of PCM harness connector. [A/T]
Measure resistance between terminal 3 of MAFS harness connector and terminal 19/C01 of ECM harness connector. [M/T]
Specification : Below 1Ohms
(4) Is the measured resistance within specification?
YES
> Go to "Check short to ground in harness" as follows.
NO
> Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
2. Check short to ground in harness.
(1) IG "OFF".
(2) Disconnect MAFS and ECM/PCM connector.
(3) Measure resistance between terminal 3 and 4 of MAFS harness connector.
Specification : Infinite
(4) Is the measured resistance within specification?
YES
> Go to "Component Inspection" procedure.
NO
> Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
COMPONENT INSPECTION
1. Check MAFS performance.
(1) IG "OFF".
(2) Connect CHA probe to terminal 3 of MAFS and CHB probe to terminal 1 of TPS connector.
(3) Warm up the engine to normal operating temperature.
(4) Measure signal waveform of MAFS and TPS together by stepping on and off the accelerator pedal.
Specification :
(5) Is the measured signal waveform(Comparison response of TPS with MAFS) O.K?
YES
> Go to "Check ECM/PCM" as follows.
NO
> Substitute with a known - good MAFS and check for proper operation.
> If the problem is corrected, replace MAFS and go to "Verification of Vehicle Repair" procedure.
2. Check ECM/PCM.
(1) IG "OFF" and disconnect MAFS connector.
(2) Connect scantool and Key "ON".
(3) Select simulation function on scantool.
(4) Simulate voltage at terminal 3 of MAFS signal connector.
(5) Does the signal value of MAFS change according to simulation voltage?
YES
> Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
NO
> Substitute with a known - good ECM/PCM and check for proper operation.
> If the problem is corrected, replace ECM/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 ECM/PCM.
Before or after testing ECM/PCM on the vehicle, use this function to reuse the ECM/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. Clear the DTCs and Operate the vehicle within DTC Enable conditions in General information.
3. Are any DTCs present ?
YES
> Go to the applicable troubleshooting procedure.
NO
> System is performing to specification at this time.
SIGNAL WAVEFORM & DATA
SPECIFICATION
