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MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS TSB Revision MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE> 13A-429 Check Conditions • Engine coolant temperature is higher than 77°C (171 °F). • Under the closed loop air/fuel ratio control. Judgment Criteria • Long-term fuel trim has continued to be −12.5 percent for 5 seconds. or • Short-term fuel trim has continued to be −25.0 percent for 5 seconds. . OBD-II DRIVE CYCLE PATTERN − OBD-II Drive Cycle − Procedure 2 − Fuel Trim Monitor . TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:) • Mass airflow sensor failed. • Injector (Number 2, 3) failed. • Incorrect fuel pressure. • Engine coolant temperature sensor failed. • Intake air temperature sensor failed. • Barometric pressure sensor failed. • Manifold absolute pressure sensor failed. • Harness damage in cylinder 2, 3 injector circuit or connector damage. • PCM failed. DIAGNOSIS Required Special Tools: • MB991958: Scan Tool (MUT-III Sub Assembly) • MB991824: V.C.I. • MB991827: USB Cable • MB991910: Main Harness A STEP 1. Using scan tool MB991958, check data list item 12: CAUTION To prevent damage to scan tool MB991958, always turn the (3) Set scan tool MB991958 to the data reading mode for item 12, Mass Airflow Sensor. (4) Warm up the engine to normal operating temperature: 80 °C to 95 °C (176°F to 203°F). • When idling, between 2.0 and 6.0 g/sec. • When 2,500 r/min, between 6.5 and 14.5 g/sec. (5) Turn the ignition switch to the "LOCK" (OFF) position. YES : Go to Step 2. − Mass Airflow Circuit , DTC P0102 − Mass Airflow Circuit Low Input , DTC P0103 − Mass Airflow Circuit High Input . AK303804AB MB991910 DATA LINK MB991824 MB991827 |