Check for damaged harness and terminals including rubber seals :
contact resistance, oxidation, corrosion, bent or broken terminals
harness connector connection, loose wires etc.
Check for poor connection between ECM and component :
backed out terminal, improper mating, broken locks and poor terminal to wire connection
ARE THE WIRES O.K ? & ARE THE CONNECTIONS O.K ?
YES
Go to "Signal Circuit Inspection" procedure
NO
Repair as necessary and go to " Verification of Vehicle Repair " procedure
DTCs listed below are stored in the scan tool
P0101/P0102/P0103/P0104
Check items with the scan tool and the multimeter
Wiring harness inspection
Sensor supply voltage from ECM
Waveform from MAFS
Specification
Resitance : below 1 Ω for open in the wire
Resitance : infinite for short to ground in the wire
Voltage : below 0.5V for short to power in the wire
Sensor supply voltage : Approx. 5V
Refer to the component and full circuit for connector configrations details
Disconnect the MAFS and then turn the ignition switch ON.
Measure the voltage between the MAFS terminal 4 and the MAFS terminal 3.
IS THERE A BATTERY VOLTAGE ?
YES
Go to step 3
NO
Repair open or short in the wire between the MAFS terminal 4 and the fuse No.21 (10A)
Repair open or short in the wire between the MAFS terminal 3 and the ECM terminal 7/C230-2
Replace the fuse if the fuse is broken.
Repair as necessary for wiring harness or connector terminal
Go to step 3
Measure the voltage between the MAFS terminal 2 and the MAFS terminal 3
IS THERE approx. 5 V ?
YES
Go to step 7
NO
Repair open or short in the wire between the MAFS terminal 2 and the ECM terminal 16/C230-2
Repair open or short in the wire between the MAFS terminal 3 and the ECM terminal 7/C230-2
Repair as necessary for wiring harness or connector terminal
Go to step 5
Measure the voltage at the ECM terminal 16/C230-2 after turning the ignition switch ON directly.
IS THERE approx. 5V ?
YES
Recheck open or short in the wire between MAFS terminal 2 and ECM terminal 16/C230-2.
Go to step 7
NO
Replace a known - good ECM and recheck. If approx. 5V is checked, replace the ECM
Go to step 7
Check the waveform at the MAFS terminal 1 and the APS terminal 2 when depressing the accelerator pedal fully one time.
IS THERE THE SIGNAL WAVEFORM PROPERLY DISPLAYED ?
YES
Go to "Verification of Vehicle Repair" procedure
NO
Replace the MAFS
Go to step 9
WAVEFORM ANALYSIS
This test should be inspected after depressing the HOLD mode from run during the sudden acceleration. As accel pedal with the MAFS is pressed down fully, the intensity of the waveform increases from less than 1V to over 4V. The waveform pattern become increasing upward rapidly when the engine speed increases. If the waveform pattern becomes distorted after the sudden acceleration, replace the MAFS
Connect the scan tool to the data link connector(DLC) and start the engine
Fix the mass air flow, engine rpm, barometric pressure sensor, injector current data and check.
Perform test drive and check the fixed current data in the overrun range after releasing the accel pedal.
① This test should be inspected above 1010 mg/st from MAFS and IAT sensor under the condition of engine 2040 < 2690 rpm (overrun range after releasing the accel pedal) and injection quantity < 0 mg/st and barometric pressure > 750 hpa and -7℃(19.4℉) < WTS 120℃(248℉) only
② Keep the above test condition of P0101 for more than 8 seconds
Check the current data during the test drive.
IS THE CURRENT DATA DISPLAYED PROPERLY ?
YES
Go to "Verification of Vehicle Repair" procedure
NO
Inspect whether or not the throttle actuator stick or normal operation and EGR valve stick or normal operation. For more detailed information, Go to "DTC P1190 Component Inspection" procedure. For more detailed information, Go to "DTC P0401 Component Inspection" procedure.
Disconnect the MAFS and then turn the ignition switch ON.
Measure the voltage between the MAFS terminal 4 and the MAFS terminal 3
IS THERE A BATTERY VOLTAGE ?
YES
Go to step 3
NO
Repair open or short in the wire between the MAFS terminal 4 and the fuse No.21 (10A)
Repair open or short in the wire between the MAFS terminal 3 and the ECM terminal 7/C230-2.
Replace the fuse if the fuse is broken.
Repair as necessary for wiring harness or connector terminal
Go to step 3
Measure the voltage for the MAFS terminal 2 and terminal 3
IS THERE approx. 5 V ?
YES
Go to step 7
NO
Repair open or short in the wire between the MAFS terminal 2 and the ECM terminal 16/C230-2.
Repair open or short in the wire between the MAFS terminal 3 and the ECM terminal 7/C230-2.
Repair as necessary for wiring harness or connector terminal
Go to step 5
Measure the voltage at the ECM terminal 16/C230-2 after turning the ignition switch ON directly.
IS THERE approx. 5V ?
YES
Recheck open or short in the wire between MAFS terminal 2 and the ECM terminal 16/C230-2.
Go to step 7
NO
Replace a known - good ECM and recheck. If approx. 5V is checked, replace the ECM
Go to step 7
Check the signal waveform at the MAFS termianl 1 and the APS terminal 2 when depressing the accelerator pedal fully one time.
WAVEFORM ANALYSIS
This test should be inspected after depressing the HOLD mode from run during the sudden acceleration. As accel pedal with the MAFS is pressed down fully, the intensity of the waveform increases from less than 1V to over 4V. The waveform pattern become increasing upward rapidly when the engine speed increases. If the waveform pattern becomes distorted after the sudden acceleration, replace the MAFS
8. IS THERE THE SIGNAL WAVEFORM PROPERLY DISPLAYED ?
YES
Go to "Verification of Vehicle Repair" procedure.
NO
Replace the MAFS
Disconnect the MAFS and then turn the ignition switch ON.
Measure the voltage between the MAFS terminal 4 and the MAFS terminal 3
IS THERE A BATTERY VOLTAGE ?
YES
Go to step 7
NO
Repair open or short in the wire between the MAFS terminal 4 and the fuse No.21 (10A)
Repair open or short in the wire between the MAFS terminal 3 and the ECM terminal 7/C230-2.
Inspect the fuse No.21 (10 A) in the dash fuse box and replace the fuse if the fuse is broken.
Repair as necessary for wiring harness or connector terminal
Go to step 3
Measure the voltage between the MAFS terminal 2 and the MAFS terminal 3
IS THERE approx. 5 V ?
YES
Go to step 7
NO
Repair open or short in the wire between the MAFS terminal 2 and the ECM terminal 16/C230-2.
Repair open or short in the wire between the MAFS terminal 3 and the ECM terminal 7/C230-2.
Repair as necessary for wiring harness or connector terminal
Go to step 5
Measure the voltage at the ECM termial 16/C230-2 after turning the ignition switch ON directly.
IS THERE approx. 5V ?
YES
Recheck open or short in the wire between MAFS terminal 2 and the ECM terminal 16/C230-2.
Go to step 7
NO
Replace a known - good ECM and recheck. If approx. 5V is checked, replace the ECM
Go to step 7
Check the signal waveform at the MAFS terminal 1 and the APS terminal 2 when depressing the accelerator pedal fully one time.
WAVEFORM ANALY
This test should be inspected after depressing the HOLD mode from run during the sudden acceleration.As accel pedal with the MAFS is pressed down fully, the intensity of the waveform increases from less than 1V to over 4V. The waveform pattern become increasing upward rapidly when the engine speed increases. If the waveform pattern becomes distorted after the sudden acceleration, replace the MAFS
8. IS THERE THE SIGNAL WAVEFORM PROPERLY DISPLAYED ?
YES
Go to "Verification of Vehicle Repair" procedure.
NO
Replace the MAFS
In this DTC P0104 case, P1522(Sensor supply voltage 1 malfunction) and P0120 (APS 1) may be detected together.
Disconnect the MAFS and then turn the ignition switch ON.
Measure the voltage between the MAFS terminal 2 and the MAFS terminal 3 after disconnection with the ignition switch ON
IS THERE approx. 5 V ?
YES
Intermittent failure, system is O.K at this time.
Check for poor connections or losse wire at the MAFS and the ECM.
Go to "Verification of Vehicle Repair" procedure.
NO
Repair open or short in the wire between the MAFS terminal 2 and the ECM terminal 16/C230-2.
Repair open or short in the wire between the MAFS terminal 3 and the ECM terminal 7/C230-2
Repair as necessary for wiring harness or connector terminal
Go to step 3
Measure the voltage at the ECM terminal 16/C230-2 after turning the ignition switch ON directly.
IS THERE approx. 5V ?
YES
Recheck open or short in the wire between the MAFS terminal 2 and the ECM terminal 16/C230-2. Go to "Verification of Vehicle Repair" procedure.
NO
Replace a known - good ECM and recheck. If approx. 5V is checked, replace the ECM