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MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS TSB Revision MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE> 13B-644 Check Conditions • At least 14 seconds have passed since the last monitor was complete. • Engine coolant temperature is higher than 76°C (169 °F). • Engine speed is at between 970 and 1,650 r/min. • Intake air temperature is higher than −10°C (14 °F). • Barometric pressure is higher than 76 kPa (22.4 in.Hg). • Vehicle speed is 30 km/h (19 mph) or more. • At least 90 seconds have passed since manifold absolute pressure sensor output voltage fluctu- • Battery positive voltage is higher than 10.3 volts. • The throttle valve is closed. • Volumetric efficiency is lower than 29 percent. • The PCM monitors for this condition for 3 cycles of 1.8 seconds each during the drive cycle. Judgement Criteria • When the EGR valve opens to the prescribed opening, when intake manifold pressure fluctua- . OBD-II DRIVE CYCLE PATTERN Refer to Diagnostic Function − OBD-II Drive Cycle − Procedure 5 − Exhaust Gas Recirculation (EGR) System Monitor . TROUBLESHOOTING HINTS (The most • Contaminated EGR valve and EGR passage. • EGR valve (stopper motor) failed. • Open or shorted EGR valve (stopper motor) cir- cuit, or connector damage. • Manifold absolute pressure sensor failed. • 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. Check the EGR system − Exhaust Gas Recirculation (EGR) System − General Information . Q: Are there any abnormalities? YES : Repair it. Then go to Step 3. |