P0102
DTC P0102 MASS OR VOLUME AIR FLOW CIRCUIT LOW INPUTComponent 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
ECM sets DTC P0102 if the ECM detects signal voltage lower than the possible range of a properly operating MAF sensor.
DTC Detecting Condition:
Schematic Diagram:
Signal Waveform And Data Part 1:
Signal Waveform And Data Part 2:
MONITOR DTC STATUS
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode.
2. Press F4 (DTAL) to select DTC information from the DTCs menu.
3. Confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.
4. Read "DTC Status" parameter.
5. Is parameter displayed "History (Not Present) fault"?
NOTE:
- History (Not Present) fault : DTC occurred but has been cleared.
- Present fault : DTC is occurring at present time.
YES - Fault is intermittent caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM memory was not cleared. Thoroughly Check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
NO - Go to next step as below.
POWER CIRCUIT INSPECTION
1. Ignition "OFF".
2. Disconnect MAF sensor connector.
3. Ignition "ON" & Engine "OFF".
4. Measure voltage between terminal 2 of the sensor harness connector and chassis ground.
Specification : Approx. B+
5. Is voltage within the specification?
YES - Go to "Signal Circuit Inspection" procedure.
NO - Check for an open or short to ground in the power supply circuit between the MAF sensor and main relay. Repair as necessary and go to "Verification of Vehicle Repair" procedure
SIGNAL CIRCUIT INSPECTION
1. With ignition ON & Engine OFF, install scan tool.
2. Monitor the "MASS AIR FLOW (V)" parameter on the Scantool data list.
Specification : Approx. 0.1 V
3. Is MAF (V) within the specification?
YES - Go to next step as below
NO - Check for open or short in signal circuit. Repair as necessary. Go to "Verification of Vehicle Repair" procedure
TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness(es) 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 "Component Inspection" procedure
COMPONENT INSPECTION
1. Engine "ON".
2. Install Scantool and monitor the "MASS AIR FLOW (V)" parameter on the Scantool data list.
Specification :
Normal value with idle after warm up : Approx. 1.0 - 1.4 V
Normal value with idle and A/C "ON" after warm up : Approx. 1.2 - 1.5 V
3. Is MASS AIR FLOW (V) within the specification?
YES - Check for poor connection between ECM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO - Check MAF for contamination, deterioration, or damage. Substitute with a known-good MAF and Check for proper operation. If the problem is corrected, replace MAF and then 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"?
YES - System performing to specification at this time. Clear the DTC
NO - Go to the applicable troubleshooting procedure.