MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS
MULTIPORT FUEL INJECTION (MFI) <2.4L>
STEP 4. Using scan tool MB991502, check data list.
a. Item 11: Heated Oxygen Sensor (front)
Voltage should fluctuate between 0
0.4 volts and 0.6 -
1.0 volts while idling after the engine has been warmed.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES : Replace the heated oxygen sensor (front). Then
confirm that the malfunction symptom is eliminated. If
NO : Go to Step 5.
STEP 5. Check the fuel pressure.
Q: Is the fuel pressure normal?
YES : Go to Step 6.
symptom is eliminated.
STEP 6. Check the following items.
a. Check the injectors for fuel leakage.
c. Check compression pressure.
d. Check the positive crank case ventilation system.
f. Check the EGR system.
(2) Then check the malfunction symptom.
Q: Is the malfunction symptom is eliminated.
YES : The check is completed.
malfunction symptom is eliminated.
INSPECTION PROCEDURE 23: Transient, Mass Emission Tailpipe Test Failure.
The test is failed when the air/fuel ratio is not
NOTE: If the three-way catalyst temperature is low
TROUBLESHOOTING HINTS (The most likely
Malfunction of air/fuel ratio control system.
Malfunction of the EGR system.