P0103
DTC P0103: Mass Airflow Circuit High InputMass Airflow Sensor Circuit Part 1:
Mass Airflow Sensor Circuit Part 2:
CIRCUIT OPERATION
The mass airflow sensor power is supplied from the MFI relay (terminal No. 4), and the ground is provided on the ECM (terminal No. 88).
A voltage that is according to the mass airflow rate is sent to the ECM (terminal No. 87) from the mass airflow sensor output terminal (terminal No. 3).
TECHNICAL DESCRIPTION
While the engine is running, the mass airflow sensor outputs voltage which corresponds to the mass airflow rate.
The ECM checks whether the voltage output by the mass airflow sensor while the engine is running is within a specified range.
DESCRIPTIONS OF MONITOR METHODS
Compare load value with mass airflow sensor output voltage.
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 Conditions
3 seconds or more have passed since the ignition switch was turned to "ON" position.
Judgement Criterion
Mass airflow sensor output voltage has continued to be higher than 4.9 volts for 2 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 24. OBD-II Drive Cycle
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are: )
Mass airflow sensor failed.
Connector damage
Harness damage
ECM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
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 mass airflow rate 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. Check harness connector A-07 at the mass airflow sensor and harness connector B-11 at the ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 3.
NO: Repair it. Then go to Step 5.
STEP 3. Check for the continuity between the mass airflow sensor connector A-07 and the ECM connector B-11.
1. Disconnect the mass airflow sensor connector A-07 and the ECM connector B-11.
2. Check for the continuity between the mass airflow sensor connector A-07 (terminal No. 4) and the ECM connector B-11 (terminal No. 88).
Should be less than 2 ohms.
Q: Does continuity exist?
YES: Go to Step 4.
NO: Repair it. Then go to step 5.
STEP 4. Replace the mass airflow sensor.
1. Replace the mass airflow sensor.
2. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 24. OBD-II Drive Cycle
3. Check the diagnostic trouble code (DTC).
Q: Is DTC P0102 set?
YES: Replace the ECM. When the ECM is replaced, register the ID code. Refer to ID Code Registration Judgment Table
NO: The inspection is complete.
STEP 5. 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 24. OBD-II Drive Cycle
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0103 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.