STEP 1. Using scan tool MB991958, check data list item 10: Mass 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 10, Mass Airflow Sensor.
(4) Warm up the engine to normal operating temperature: 80°C to 95°C (176°F to 203°F).- The standard value during idling should be between 1,350 and 1,670 millivolts.
- When the engine is revved, the output voltage should increase according to the increase in engine speed.
(5) Turn the ignition switch to the "LOCK" (OFF) position.
Is the sensor operating properly?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions . Go to Step 2.
STEP 2. Check harness connector A-07 at mass airflow sensor for damage.
STEP 3. Measure the power supply voltage at mass airflow sensor harness side connector A-07.
(1) Disconnect the connector A-07 and measure at the harness side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal No. 1 and ground.- Voltage should be battery positive voltage.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is battery positive voltage (approximately 12 volts) present?
Go to Step 5. Go to Step 4.
STEP 4. Check harness connector A-37X at MFI relay for damage.
STEP 5. Check harness connector B-27 at ECM for damage.
STEP 6. Measure the sensor output voltage at ECM connector B-27 by using power plant ECU check harness special tool MB992110.
(1) Disconnect all ECM connectors. Connect the power plant ECU check harness special tool MB992110 between the separated connectors.
(2) Start the engine.
(3) Measure the voltage between terminal No. 87 and ground.- When the engine is revved, voltage should be increase in response to revving.
Is the measured voltage normal?
Go to Step 9. Go to Step 7.
STEP 7. Check for open circuit and short circuit to ground between mass airflow sensor connector A-07 (terminal No. 3) and ECM connector B-27 (terminal No. 87).
STEP 8. Replace the mass airflow sensor.
STEP 9. Using scan tool MB991958, check data list item 10: Mass Airflow Sensor.
(1) Start the engine and run at idle.
(2) Set scan tool MB991958 to the data reading mode for item 10, Mass Airflow Sensor.
(3) Warm up the engine to normal operating temperature: 80°C to 95°C (176°F to 203°F).- The standard value during idling should be between 1,350 and 1,670 millivolts.
- When the engine is revved, the output voltage should increase according to the increase in engine speed.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the sensor operating properly?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions . Replace the ECM (Refer to, Removal and Installation ). Then go to Step 10.
STEP 10. 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 . (2) Check the diagnostic trouble code (DTC).
Is DTC P0102 set?
Retry the troubleshooting. The inspection is complete.