P0103
DTC P0103 MASS OR VOLUME AIR FLOW CIRCUIT HIGH INPUTComponent Location:
COMPONENT LOCATION
GENERAL DESCRIPTION
The mass air flow sensor (MAF) is located between the air cleaner assembly and throttle body. The MAF uses a hot film type sensing element to measure the mass of intake air entering the engine. This hot film type air flow sensor consists of a hot film sensor, housing and metering ducts. Mass air flow rate is measured by detection of heat transfer from a hot film probe. The change in air flow rate causes change in the amount of heat being transferred from the hot film probe surface to the air. A large amount of intake air represents acceleration or high load condition while a small amount of intake air represent declaration or idle. The mass of intake air should increase at acceleration and be stable during constant engine speed. The PCM uses this information to determine the injection duration and ignition timing for the desired air-fuel ratio.
DTC DESCRIPTION
If MAF output voltage is higher than 4.8 V, the PCM determines that a fault exists and a DTC is stored.
DTC Detecting Condition:
Schematic Diagram:
MONITOR SCANTOOL DATA
1. Connect scantool to Data Link Connector(DLC).
2. Warm up the engine to normal operating temperature.
Specification:
3. Monitor the "MAF VOLTAGE" parameter on scantool
Specification
4. Is the sensor's signal within specifications?
YES: 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, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
NO: Go to "W/Harness Inspection" procedure.
TERMINAL & 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 Signal Circuit Inspection procedure.
SIGNAL CIRCUIT INSPECTION
1. Check voltage
1. Ignition "OFF"
2. Disconnect MAF sensor connector.
3. Ignition "ON" & Engine "OFF"
4. Measure voltage between terminal 1 of MAF sensor harness connector and chassis ground.
Specification: Below 1 V
5. Is the measured voltage within specifications?
YES: Go to "Component Inspection" procedure.
NO: Go to Check for short to battery in harness" as below.
2. Check for short to battery in harness
1. Ignition "OFF"
2. Disconnect MAF sensor connector.
3. Measure resistance between terminal 1 and 2 of MAF sensor harness connector.
4. Measure resistance between terminal 1 and 4 of MAF sensor harness connector.
Specification: Infinite
5. Is the measured resistance within specifications?
YES: Go to "Ground Circuit Inspection" procedure.
NO:
- Check short to battery in signal harness.
- Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
GROUND CIRCUIT INSPECTION
1. Check for open in harness
1. Ignition "OFF"
2. Disconnect MAF sensor and PCM connector.
3. Measure resistance between terminal 1 of MAF sensor harness connector and chassis ground.
Specification: Approx. below 1 Ohms
4. Is the measured resistance within specifications?
YES: Go to "Component Inspection" procedure.
NO:
- Check open in harness between MAFS connector and PCM connector.
- Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.
COMPONENT INSPECTION
1. Visual Inspection
1. Check the MAF for contamination, deterioration, or damage.
2. Is the MAF contaminated, deteriorated or damaged?
YES: Repair or replace as necessary and Go to "Verification of Vehicle Repair" procedure.
NO: Go to "Check MAF" as below.
2. Chart MAF
1. Ignition "ON" & Engine "ON"
2. Install Scantool and select the "MAF SENSOR" parameter on the CURRENT DATA.
3. Monitor signal waveform of the "MAF SENSOR" on the Scantool.
Check that MAF value is increased correspondently with TPS when pressing accelerator pedal.
4. Is the measured signal waveform of MAF sensor displaying correctly?
YES: Go to "Check PCM" as below.
NO:
- Substitute with a known - good MAF and check for proper operation.
- If the problem is corrected, replace MAF and go to "Verification of Vehicle Repair" procedure.
3. Check PCM
1. Ignition "OFF"
2. Connect Scantool and Ignition "ON"
3. Select simulation function on scantool.
4. Simulate voltage at terminal 1 of MAF sensor signal connector.
5. Does the signal value of MAF sensor changes 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 PCM and check for proper operation.
If the problem is corrected, replace PCM 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. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs.
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions.
4. Monitor that all readiness tests have been verified as "Complete"
5. Are any DTCs present?
YES: Go to the applicable troubleshooting procedure.
NO: System is performing to specification at this time.