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TROUBLESHOOTING MULTIPORT FUEL INJECTION (MPI) <4G1> 13B-125 Code No. P0300: Random/Multiple Cylinder Misfire Detected OPERATION • Refer to Code No. P0201: No. 1 injector system • Refer to Code No. P0202: No. 2 injector system • Refer to Code No. P0203: No. 3 injector system . • Refer to Code No. P0204: No. 4 injector system . FUNCTION • If a misfire occurs while the engine is running, the engine speed changes for an instant. • The engine-ECU checks for such changes in engine speed. TROUBLE JUDGMENT Check Conditions • Engine speed is more than 500 r/min and is less than 4,500 r/min. • Engine coolant temperature is more than -10°C. • Volume efficiency is more than 35% • Adaptive learning is completed for the vane which generates a crankshaft position signal. • While the engine is running, excluding gear shift- ing, deceleration, sudden acceleration/decelera- • When the variation in the throttle valve opening angle is small. Judgement Criterion • Misfire occurred more frequently than the limit during the last 200 revolutions Or • Misfire occurred more than the limit during the last 1,000 revolutions PROBABLE CAUSES • Ignition system related part(s) failed • Failed crank angle sensor • Incorrect air-fuel ratio • Low compression pressure • Failed fuel system • Failed engine coolant temperature sensor • Skipping of timing belt teeth. • Failed engine-ECU DIAGNOSIS PROCEDURE STEP 1.M.U.T.-III data list • Item No. 22: Crank angle sensor OK: Keep the engine speed constant to make Q: Is the check result normal? YES : Go to Step 2 . NO : Check crank angle sensor system (Refer to STEP 2. M.U.T.-III data list • Refer to Data List Reference Table . a. Item No. 21: Engine coolant temperature sensor c. Item No. 82: Short-term fuel compensation Q: Are the check results normal? YES : Go to Step 3 . NO : Perform the diagnosis code classified check STEP 3. Check ignition coil spark. Q: Is the check result normal? YES : Go to Step 4 . NO : Check ignition circuit system (Refer to Main Index Group TOC |