P0101
DTC P0101: Volume Airflow Circuit Range/Performance ProblemVolume Airflow Sensor Circuit Part 1:
Volume Airflow Sensor Circuit Part 2:
CIRCUIT OPERATION
- The volume airflow sensor power is supplied from the MFI relay (terminal No.4), and the ground is provided on the ECM (terminal No.34).
- 5-volt power is applied to the volume airflow sensor output terminal (terminal No.3) from the ECM (terminal No.61). The volume airflow sensor generates a pulse signal when the output terminal and ground are opened/closed (opened/short).
- The volume airflow reset signal is input by the ECM (terminal No.19) to the volume airflow sensor (terminal No.7).
TECHNICAL DESCRIPTION
- While the engine is running, the volume airflow sensor outputs a pulse signal which corresponds to the volume of airflow.
- The ECM checks whether the frequency of this signal output by the volume airflow sensor while the engine is running is at or above the set value.
- When the throttle position sensor output voltage is low, the ECM causes the power transistor to be "ON" to send an airflow sensor reset signal to the airflow sensor. In response to the reset signal, the airflow sensor resets the filter circuit and improves the ability of the airflow sensor to measure the amount of air in a small air intake region.
DESCRIPTIONS OF MONITOR METHODS
- Compare load value with volume airflow sensor output frequency.
MONITOR EXECUTION
- Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Not applicable
Sensor (The sensor below is determined to be normal)
- Throttle position sensor
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flow Chart
Check Conditions
- Throttle position sensor output voltage is 2 volts or lower.
- Engine speed is lower than 2,000 r/min.
Judgment Criterion
- Volume airflow sensor output frequency has continued to be 1,000 Hz or higher for 2 seconds.
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flow Chart
Check Conditions
- Throttle position sensor output voltage is 1.5 volts or higher.
- Engine speed is higher than 2,000 r/min.
Judgment Criterion
- Volume airflow sensor output frequency has continued to be 60 Hz or lower for 2 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 7. OBD-II Drive Cycle Pattern Lists
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are: )
- Volume airflow sensor failed.
- Open or shorted volume airflow sensor circuit, harness damage, or connector damage.
- ECM failed.
- Air leak between volume airflow sensor and throttle body.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B
STEP 1. Using scan tool MB991958, check data list item 12: Volume Airflow Sensor.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Start the engine and run at idle.
3. Set scan tool MB991958 to the data reading mode for item 12, Volume Airflow Sensor.
4. Warm up the engine to normal operating temperature: 80 degrees C to 95 degrees C (176 degrees F to 203 degrees F).
- The standard value during idling should be 10 Hz or more.
- When the engine is revved, the frequency should increase according to the increase in engine speed.
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: It can be assumed that this malfunction is intermittent.
NO: Go to Step 2.
STEP 2. Measure the reset signal voltage at volume airflow sensor connector B-105 by backprobing.
1. Do not disconnect connector B-105.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No.7 and ground by backprobing.
- Voltage should be between 6.0 and 9.0 volts.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 6.0 and 9.0 volts?
YES: Go to Step 5.
NO: Go to Step 3.
STEP 3. Check harness connector B-105 at volume airflow sensor and harness connector C-121 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 4.
NO: Repair or replace it. Then go to Step 9.
STEP 4. Check for short circuit to ground between volume airflow sensor connector B-105 (terminal No.7) and ECM connector C-121 (terminal No.19).
Q: Is the harness wire in good condition?
YES: Replace the volume airflow sensor. Then go to Step 9.
NO: Repair it. Then go to Step 9.
STEP 5. Measure the reset signal voltage at volume airflow sensor connector B-105 by backprobing.
1. Do not disconnect connector B-105.
2. Start the engine and run at idle.
3. Measure the voltage between terminal No.7 and ground by backprobing.
- When the engine idling, voltage should be 1.0 volt or less.
- When the engine speed is 3,000 r/min, voltage should be between 6.0 and 9.0 volts.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage within the specified range?
YES: Go to Step 8.
NO: Go to Step 6.
STEP 6. Check harness connector B-105 at volume airflow sensor and harness connector C-121 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 7.
NO: Repair or replace it. Then go to Step 9.
STEP 7. Check for open circuit and harness damage between volume airflow sensor connector B-105 (terminal No.7) and ECM connector C-121 (terminal No.19).
Q: Is the harness wire in good condition?
YES: Replace the ECM. Then go to Step 9.
NO: Repair it. Then go to Step 9.
STEP 8. Replace the volume airflow sensor.
1. Replace the volume airflow sensor.
2. Carry out a test drive with the drive cycle pattern. Refer to, Diagnostic Function - OBD-II Drive Cycle - Pattern 7. OBD-II Drive Cycle Pattern Lists
3. Check the diagnostic trouble code (DTC).
Q: Is DTC P0101 set?
YES: Replace the ECM. Then go to Step 9.
NO: The inspection is complete.
STEP 9. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to, Diagnostic Function - OBD-II Drive Cycle - Pattern 7. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0101 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.