P0102
DTC P0102: Volume Airflow Circuit Low InputVolume 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).
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.
DESCRIPTIONS OF MONITOR METHODS
- Volume airflow sensor output frequency is out of specified range.
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)
- Not applicable
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flow Chart
Check Condition
- Engine speed is higher than 500 r/min.
Judgment Criterion
- Volume airflow sensor output frequency has continued to be 3.3 Hz or lower for 2 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23. 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.
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 power supply 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.4 and ground by backprobing.
- Voltage should be battery positive voltage.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts) present?
YES: Go to Step 5.
NO: Go to Step 3.
STEP 3. Measure the power supply voltage at volume airflow sensor harness side connector B-105.
1. Disconnect connector B-105 and measure at the harness side.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No.4 and ground.
- Voltage should be battery positive voltage.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts) present?
YES: Go to Step 4.
NO: Repair harness wire between MFI relay connector B-12X (terminal No.4) and volume airflow sensor connector B-105 (terminal No.4) because of open circuit or short circuit to ground. Then go to Step 13.
STEP 4. Check harness connector B-105 at the volume airflow sensor for damage.
Q: Is the harness connector in good condition?
YES: Repair harness wire between MFI relay connector B-12X (terminal No.4) and volume airflow sensor connector B-105 (terminal No.4) because of harness damage. Then go to Step 13.
NO: Repair or replace it. Then go to Step 13.
STEP 5. Check harness connector B-105 at volume airflow sensor for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 6.
NO: Repair or replace it. Then go to Step 13.
STEP 6. Measure the sensor supply voltage at volume airflow sensor harness side connector B-105.
1. Disconnect connector B-105 and measure at the harness side.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No.3 and ground.
- Voltage should be between 4.8 and 5.2 volts.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.8 and 5.2 volts?
YES: Go to Step 9.
NO: Go to Step 7.
STEP 7. Check harness connector C-119 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 8.
NO: Repair or replace it. Then go to Step 13.
STEP 8. Check for short circuit to ground between volume airflow sensor connector B-105 (terminal No.3) and ECM connector C-119 (terminal No.61).
Q: Is the harness wire in good condition?
YES: Replace the ECM. Then go to Step 13.
NO: Repair it. Then go to Step 13.
STEP 9. Check for continuity at volume airflow sensor harness side connector B-105.
1. Disconnect connector B-105 and measure at the harness side.
2. Check for the continuity between terminal No.5 and ground.
- Should be less than 2 Ohms.
Q: Does continuity exist?
YES: Go to Step 12.
NO: Go to Step 10.
STEP 10. Check harness connector C-121 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 11.
NO: Repair or replace it. Then go to Step 13.
STEP 11. Check for open circuit and harness damage between volume airflow sensor connector B-105 (terminal No.5) and ECM connector C-121 (terminal No.34).
Q: Is the harness wire in good condition?
YES: Replace the ECM. Then go to Step 13.
NO: Repair it. Then go to Step 13.
STEP 12. Check harness connector C-121 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Replace the volume airflow sensor. Then go to Step 13.
NO: Repair or replace it. Then go to Step 13.
STEP 13. 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 23. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0102 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.