P0101
P0101Component Location:
General Description
The Mass Air Flow Sensor (MAFS) is located between the air cleaner assembly and the throttle body. The MAFS 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 conditions while a small amount of intake air represents deceleration or idle. The mass of intake air should increase at acceleration and be stable during constant engine speed. The ECM uses this information to determine the injection duration and ignition timing for the desired air/fuel ratio.
DTC Description
The difference between values coming from the MAF Sensor and those are calculated is analyzed. This difference, or error, is then compared to high and low limit calibration values, which are functions of engine speed. PCM compares the difference between MAFS output and calculated flow rate value while enable condition is met.
If the actual air flow is higher or lower than calculated value(threshold) for more than 2 min. 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:
Specification:
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 F5(INFO) to check DTC's information from the DTCs menu
4. Read "DTC Status" parameter.
5. Is parameter displayed "Present fault"?
YES
a. Go to "Component Inspection" procedure.
NO
a. Fault is intermittent caused by PCM memory was not cleared after repair.
Erase DTC and drive the vehicle to satisfy the enable condition then, go to "Component Inspection" procedure.
Component Inspection
1. Visual Inspection
1. Check that MAFS is damaged, contaminated or deformed.
2. Check the air cleaner is clogged.
3. Has a problem been found ?
YES - Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
NO - Go to "Check MAFS" as follows
2. Check MAFS
1. IG "OFF" and install scantool
2. ENG "ON" and monitor "MAFS" data.
3. Monitor signal waveform at terminal 1 of MAFS with scantool.
Specification :Signal waveform will be displayed as follows. (Be aware that the signal of MAFS is not voltage display but frequency display.)
4. Are both service data and signal wave form dispayed correctly ?
YES - Go to "Verification of Vehicle Repair" procedure.
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.
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 F5(INFO) 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"?
YES - System performing to specification at this time. Clear the DTC
NO - Go to the applicable troubleshooting procedure.